Honda-SOHC
SOHC.co.uk Forums => Project Board => Topic started by: Neilw on January 30, 2026, 04:57:28 PM
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Hi All,
I've just retired and purchased a project CB550 F2, 32000 miles with a view to restoring it so it's not rusty, all works, and safe to ride in the summer.
Some history on the Bike: it was originally sold on eBay in December 2025 by someone selling project bikes for his brother-in-law, who had passed away. It was listed as a non-runner, but had run 4 years ago and had been stored since.
The new owner wanted a small project, didn't work on getting it roadworthy, doing some cosmetic work before quickly flipping it to me, making a few hundred quid in the process.
So my plan is to get it running first, make sure the engine is good and go from there. I'll probably strip it down, repair and clean it, replace/renew the serviceable parts, and repaint the frame.
Then enjoy some rides in the summer.
I've never done anything like this before, but I am happy to dive in and learn as I go.
I've stuck a new battery in it and run into my first problem: the start button is dead.
The solenoid is good, and the starter motor is too. I shorted the solenoid to see if it would turn the bike over, and it did.
I opened the switch on the handlebars because it was filthy, so I've cleaned it as best I can. However, the push switch for the start button spring is not good, so I don't think good contact was being made. I tried to disassemble it and have managed to break a contact already, and it's mighty fiddly that I doubt I can get the switch together without removing the loom bit. going to figure out how to do that now. What is my likely success rate of repairing this and getting it working again?
Are there serviceable parts available? I can't find a parts list, just for the whole unit.
Also, there is something up with my fuse box. It appears one of the fuses has a loop with another fuse on it. If I take it out and just use the fuse, there is no power. Could it be a fault in that particular fuse? When I reinstate it, power is restored.
Thanks for reading, I'll post as I go with pics, and I'm sure I'll have management questions.
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Depends on which RH switch you have as to the chances of repair, the us type that the headlamp goes through is slim
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Depends on which RH switch you have as to the chances of repair, the us type that the headlamp goes through is slim
The cables pass through the handlebars and terminate at a junction box below the coils (not into the headlamp). As you can see from the photo, these are the two electrodes, one of which I broke. Am wondering whether i can repair if there are parts available.
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Your fuse box has had a by-pass op! 🤭 Probably because these old fuse box’s become fair. If you’re not bothered too much about what’s behind the side panel you could fit a spade type fuse box. Thinking about doing it on my 550.
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If that white? Plastic piece is cracked/broken you need a new switch
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I seem to recall there is a small pin on the back of the button, a small spring goes over this, which makes the button return. Can you feel this in operation, the spring normally rusts through after some years and the button tends to just flop around. The pin on the button goes through a small hole on an internal plate with the spring pushing against this plate for its resistance. As you press the button the pin goes further through and connects with the contact on the other wire, this activates the starter solenoid. However your switch is so dirty and full of crap I doubt this was happening. Unless the internal plates are broken or missing it should be a simple fix.
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I seem to recall there is a small pin on the back of the button, a small spring goes over this, which makes the button return. Can you feel this in operation, the spring normally rusts through after some years and the button tends to just flop around. The pin on the button goes through a small hole on an internal plate with the spring pushing against this plate for its resistance. As you press the button the pin goes further through and connects with the contact on the other wire, this activates the starter solenoid. However your switch is so dirty and full of crap I doubt this was happening. Unless the internal plates are broken or missing it should be a simple fix.
It's exactly as you've described. The spring appears to be broken, and I managed to break the connection to the white piece of plastic. Assuming I can solder the broken wire and replace the spring, I have no idea how to reassemble, as the spring needs to be fully compressed so the other two parts can be slotted in for it all to work, and you can't get tools or fingers in there to do it.
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You need the optionaly japanes spider with mechanical degree OR a lot of luck!
I have spent literaly hours trying to repair one and very, very ocasionaly only 10 mins.
The least frustrating way, but not the cheapest is a new switch
Just for a sxreenshot from CMSNL
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Also this ebay one BUT the wire colours are different
Sorry forgot to attach, done now
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I’m saying this without trying to promise anything. I’ve been extremely unwell recently and am still unable to do a lot of things I used to be able to do. I do tend to collect broken switchgear and have built up a supply of some of the internal parts, I may have just what you want or I may not. The problem is looking for them, that may be beyond me at present depending on where I decided to store them. Post some pics up of what you think is broken and I’ll see if I can help out.
I personally find fixing these switches easy, not sure why, perhaps I can good fingers (although not at present). If you’re unable to fix it I may be able to have a crack at it, I think I can manage little jobs like that.
Give the switch housing a good wash out with petrol or similar, see what we are facing, really grotty in there.
I’d say someone had bodged the harness up somewhat badly.
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Hi Neil
Just seen this on eBay if you’re interested.
Regards Ken
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You might find if the switch is not exactly the same the internal parts maybe
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Avoid avoid avoid. No light switches in that switch.
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Correct Ken, i didnt look close just googled the part number from cms, it was stupid o'clock in my defense, appologies to op
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No Problem Bryanj
I just thought that even if the assembly was not exactly the same the internal might be , big companies like Honda will also try and use existing designs instead of re inventing new parts every time to keep design and production costs down.
I did have slot of issues with my switches when I rebuilt my bike but managed to re fettle everything and now it’s working well.
These switches when exposed to the elements over long periods of time just disintegrate into a pile of rust, I actually totally retired my bike because every time I fixed one thing something else went wrong so I decided to rebuild the whole wiring loom.
During this adventure I found lots of corrosion throughout the loom with lots of wire nearly corroded through so well work doing, sorry waffling on too much.
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In the US that white plastic bit has 2 switches in it and turns the always on headlamp off before connecting the starter, this tends to make the white bit even more brittle till it crumbles to dust, somebody on us forum did 3d print some
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Although you’d expect the internals to be the same, in many cases they aren’t. The starter button for instance can be either a one wire or two wire installation. The 550 uses the two wire version but many others used a one wire with the button earthing that wire and activating the starter motor. IIRC the early 500 used both versions depending on the market they were intended for.
I actually bought one of those non lighting switchgear. The wires aren’t long enough for the 550F, which have exceptionally long wires. I’m not sure if the internals are the same, never got round to checking tbh. I do have a spare 550f right hand switchgear but I’m loath to sell as it’s my just in case spare and is unique in its look.
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First Update
The bike is pretty clean, no major rust anywhere, but both the mudguards have pitting and some cracks, which have been masked with silver paint. I'll decide later what to do with them in the long term. I got a quote for fixing and rechroming them, but it seems steep at £480!
In any case, there are more important things to address.
My first assessment has revealed:
- RH Handle Bar switch broken - I did it trying to get it to work, but the bike wouldn't start on the button - so needs fixing/replacing.
- Most rubber parts on the bike are hard and perished, so all need replacing.
- Brake lights don't work, nor the horn, nor the lights on the clocks.
- The fuse box is damaged; will replace with a more modern unit from Hondaman.
- The saddle pan is rusted through in places and needs replacing - previous owner has bodged fibreglass to make it sturdy.
- Grab rail is missing
- The Fuel tank is completely clean inside, no rust and no liner material that I can see, so that's one less job to worry about!
- There is a small amount of paint damage on the side panels, and they lack decals, as does the tank.
- Some sketchy-looking wiring.
- THe Front brake binds a bit, back is ok, but both will need reconditioning.
Engine
The engine starts and produces white smoke. It wouldn't idle, but at least it started!
I've performed a compression test and the results aren't great.
No1 - 125 psi, then with a drop of oil in the clyinder 142.
No2 - 60 psi then 100 psi.
No3 - 66 psi then 140 psi.
No4 - 115 psi then 125 psi.
I assume i should just concentrate on checking the engine over now, before ordering more parts, so unless other's experience suggests otherwise i'll take the top end apart and have a look at the head, valves seats, pistons, bores and rings before deciding whether a rebuild of the top end will fix things or there is something more terminal. Unless of course i've missed a step!
Some general pics included.
I'll stop ordering other parts untill i know i have a decent engine,
[/list]RH Handle Bar switch broken - i did it, but bike wouldn't start on the button - so needs fixing/replacing.
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Valves and seats first then pistons/bores
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Valves and seats first then pistons/bores
I take it that's the order I do them in? But do both while i have the top end apart?
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Yes to both as when you remove the head it disturbs the base and if you dont replace gasket and O rings it may well leak later
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Valves and seats first then pistons/bores
Update 5th Feb 2026
I've stripped the top end down and it doesn't really look too bad. I'll post some pics later today.
I have a question about the Piston rings. I've managed to break the top one on 3 of the pistons while removing them from the bike. I always planned to replace the rings, but - how do i know what size are in there and what size to get? I have some feeler gauges, but I don't have a micrometre to measure the bore. Is there a straightfoward way to determine what you have and what to get?
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Normaly it will have the size near the end of thecring, if nothing suspect standard.
In all honesty you should be able to measure sizewith a steel rule down to 1/4 of a mm which is the step sizes for rebore, or buy a pair of cheap vernier calipers of ebay.
You cant buy individual rings they come in sets for a piston
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The switch has had 50 years of use and abuse ☹️ and although it is nice to repair things and keep them going I have replaced mine with after market ones from David silver. It’s not the cheapest option but will help give you the best chance of reliability.
I would also order a new fuse box while you are at it, the one you have has already had a bypass so is probably knackered, as they tend to be.
Also give the harness a clean, pull the connectors apart to make sure they are clean, check and clean all the earth connections. Then sort of take it from there, checking, cleaning and redoing parts of the electrical system as needed.
The electrical system is the part of the bike that has the greatest ability to leave you sat at the side of the road waiting for the AA. it’s worth spending some time and money on if you are going to use the bike.
Good luck with the project, they are nice bikes to work on.
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The switch has had 50 years of use and abuse ☹️ and although it is nice to repair things and keep them going I have replaced mine with after market ones from David silver. It’s not the cheapest option but will help give you the best chance of reliability.
I would also order a new fuse box while you are at it, the one you have has already had a bypass so is probably knackered, as they tend to be.
Also give the harness a clean, pull the connectors apart to make sure they are clean, check and clean all the earth connections. Then sort of take it from there, checking, cleaning and redoing parts of the electrical system as needed.
The electrical system is the part of the bike that has the greatest ability to leave you sat at the side of the road waiting for the AA. it’s worth spending some time and money on if you are going to use the bike.
Good luck with the project, they are nice bikes to work on.
I've ordered a replacement switch unit, figured it would be the cheaper option, and if I can repair the original when I'm finished, I'll do that and sell it on (I love the patenia on it!).
Regarding the electrics - I plan to upgrade the fuse box and maybe at the end put electronic ignition in, but that's a long way off.
The wiring and connectors, especially under the left cover, are dusty with 50 years of accumulated grime. How do i go about cleaning the mess. Do i spray it with something?
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If you are ordering Hondamans fusebox consider his electronic ignition box, it keeps the points but reduces the current flow so points dont wear out.
No matter what some members say the 500/550 has only just enough generator power, especially with the later halogen headlight and needs to be turning at quite high revs to charge, most electronic ignitions use more power than points as they leave the coil "turned on" for longer and if you fit 3 ohm coils its even worse.
Setting points and timing can take a bit of time but once do is usually ok for at least 3,000 miles so how much riding are you going to do in a year?
If you insist i still have a couple of dyna knock offs i imported last year for a reasonable price, me i am sticking to points
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I second those comments. Plus, as the harness ages the connectors start to deteriorate and more and more resistance builds up lowering the charging even further. Heavy traffic and constant use of brake lights and indicators can drain the battery to the extent that the engine stops.
Using the Hondaman fuse box also stops the theft problem the old fuse box had which meant you could get the bike started using no tools at all.
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I second those comments. Plus, as the harness ages the connectors start to deteriorate and more and more resistance builds up lowering the charging even further. Heavy traffic and constant use of brake lights and indicators can drain the battery to the extent that the engine stops.
Using the Hondaman fuse box also stops the theft problem the old fuse box had which meant you could get the bike started using no tools at all.
Do you think its worth just replacing the harness for one from David Silvers to head off any potential problems, alongside the new upgraded fusebox?
Also, I've just got to the cleaning stage, engine, carbs and purchased the Berryman® Chem-Dip® - Carburettor & Parts Cleaner, as I saw a demo on YouTube. But the instructions that came with it have scared the life out of me, and I don't think I could use the product safely. What do others use to clean the grease, carbon desposts and the carbs?
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Lots of negative reports on the DS harnesses, wrong colours used and no literature to tell you what they are meant to be.
My harness I removed from my 500 is actually from a 550F2 I bought as a write off back in the late 70s. I liked the fact it had multiple fuses instead of the single one on the 500 so I ended up with a lot of 550 parts on my 500, something I’m quite happy with. A few years ago I bought a NOS F2 harness still sealed in its bag. My existing harness is in really good condition with just one splice where I installed a dual ignition lock. Easy to revert back to standard. Not sure yet what harness I’ll use when I rebuild the bike later this year. I also have a brand new aftermarket harness made by one of our members on here called Big Al. It’s very good. That’s for sale if you’re interested.
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Small Update
I've been working on taking the head apart, with a view to relapping the valves and also painting. I've decided to get the top-end soda blasted, as it's taking me ages to get them clean and the paint removed.
I had a go at cleaning the tops of the pistons; they all have a coating of carbon, which I've mostly removed.
However, at the edge of one of the pistons are two small chips, almost opposite each other, and I wonder if the piston is still okay to use? There is no damage in the cylinder, it was from. See pics.
One of the pistons has some light pitting, which I can't really feel with my finger and may polish out. Is this something to worry about?
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Bryan or Nurse Julie can probably comment further but I am aware of the pistons failing on the edges like this as a result of previous owners ragging the engine before it is properly warm. You have likely caught it just in time, not sure if I would reuse them.
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Thats probably due to corrosion, worst one where valve was open, will run for a 2-3000 mile a year fun bike, not good for one used daily and/or hard.
You could rering it and hone but hone may give too big a piston clearance.
Piston kits or rings from cruzinimage in japan, std same price as oversize so you pay extra for rebore and then its as new if you wish
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Thats probably due to corrosion, worst one where valve was open, will run for a 2-3000 mile a year fun bike, not good for one used daily and/or hard.
You could rering it and hone but hone may give too big a piston clearance.
Piston kits or rings from cruzinimage in japan, std same price as oversize so you pay extra for rebore and then its as new if you wish
I like the bike to run for probably less than 2,000 miles a year. I've broken the rings on 3 of the pistons, so you think I could get away with a light hone and std rings, keeping the pistons I currently have? The ones with the chips on the edge are a bit sharp, so can I just file those down a touch to remove the burr, or does that need to be replaced?
If i can avoid a rebore i'd like to.
When I removed the values, a couple weren't making a good seal, which I guess could be the cause. I'll lap those to improve things.
I'm new to all this, so I'd like to make a reasonable decision that gives me the best chance of having an engine without undoing everything. Your advice is greatly appreciated.
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You need to measure the bores to work out if they are still within spec to use those pistons with new rings. Personally, I would not use those old pistons anyway, I would have a rebore and fit a new oversized piston / ring kit. If you try and cut corners or do things on the cheap, these old engines have a habit of coming back and kicking you in the backside.
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You need to measure the bores to work out if they are still within spec to use those pistons with new rings. Personally, I would not use those old pistons anyway, I would have a rebore and fit a new oversized piston / ring kit. If you try and cut corners or do things on the cheap, these old engines have a habit of coming back and kicking you in the backside.
Thank you, i assume i'd have to get a rebore on all the cylinders to keep things uniform?
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You need to measure the bores to work out if they are still within spec to use those pistons with new rings. Personally, I would not use those old pistons anyway, I would have a rebore and fit a new oversized piston / ring kit. If you try and cut corners or do things on the cheap, these old engines have a habit of coming back and kicking you in the backside.
Thank you, i assume i'd have to get a rebore on all the cylinders to keep things uniform?
Yes, all 4.
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Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.
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Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.
Other than Bryan, do you have any recommendations? Sorry for the stupid question, but would I just send someone the Cylinder head, or would they need more of the engine?
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Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.
Other than Bryan, do you have any recommendations? Sorry for the stupid question, but would I just send someone the Cylinder head, or would they need more of the engine?
You just pack the barrels in a box and send in the post, Parcel Force costs about £12, 48 hour tracked. It was very, very rare for us to see customers, complete engines were delivered by couriers on pallets and heads or barrels came by and were returned by normal post.
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Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.
Other than Bryan, do you have any recommendations? Sorry for the stupid question, but would I just send someone the Cylinder head, or would they need more of the engine?
You just pack the barrels in a box and send in the post, Parcel Force costs about £12, 48 hour tracked. It was very, very rare for us to see customers, complete engines were delivered by couriers on pallets and heads or barrels came by and were returned by normal post.
That's brilliant, thank you. I've just spoken to D&M Engineering who work on Classic Hondas, so fit the bill regarding experience.
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Also, only get the rebore done by someone who understands Hondas tight tolerances. We've retired now but Bryan may be able to do it for you.
Other than Bryan, do you have any recommendations? Sorry for the stupid question, but would I just send someone the Cylinder head, or would they need more of the engine?
You just pack the barrels in a box and send in the post, Parcel Force costs about £12, 48 hour tracked. It was very, very rare for us to see customers, complete engines were delivered by couriers on pallets and heads or barrels came by and were returned by normal post.
That's brilliant, thank you. I've just spoken to D&M Engineering who work on Classic Hondas, so fit the bill regarding experience.
They will need the new pistons as well to measure the clearance accurately.
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They will need the new pistons as well to measure the clearance accurately.
Thank you. i thought it best that they supply them as they can get the correct ones to fit the work they do.
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Personally I would not recommend that. From experience I know that firms take every opportunity to make as much profit as possible. So they’ll supply whatever they can find that makes the most money. They may last but most don’t. 2 years or so later and you need it done again due to a poor job. Do it once and do it right.
Try and find genuine pistons and rings if at all possible. Not as cheap as say Cruzinimage but better quality.
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Try and find genuine pistons and rings if at all possible. Not as cheap as say Cruzinimage but better quality.
I've had a good look for NOS oversize pistons and rings as a set, and i can't find any, most sites seem to sell pattern parts. i'll keep looking - are any of the aftermarket brands better than others?
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Have you had the bore measured yet? First oversize 0.25 may not be enough to clear the bore, 0.5 might be a better bet. CMS used to sell the rings in that size although they come in non standard boxes even though they claim they are genuine Honda. I reported them to Honda for that. They are made by the same manufacturer as the genuine rings though. I did have some spare 0.5 genuine Honda pistons but can’t remember how many I have, at least 2 maybe 3.
The other alternative is to risk staying standard. They are shed loads of standard pistons around, second hand as well. Someone on here will have a full set after having a bore. Replace the pistons and buy some genuine standard rings, should be some of those around as well. Use a set of new standard rings and check the end gap and see what it comes out as, still in spec, stay standard. If out of spec then rebore the barrels.
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I can find 2 sets of 0.5 oversize rings and 2 genuine 0.5 oversize pistons. However Cruzinimage will be much cheaper, I'm personally not a fan of Cruzinimage as I hear bad things being said of them on the USA site amongst others, especially on ring quality.
Oddly I'm going through the same as you. I have a 500 engine which I'm converting to a 550 set of barrels, I had one set of barrels ceramic coated and then found a mark on the bores that meant I had to consider a rebore. I decided to go 0.5, got new rings and for some reason I ended up with more 0.5 pistons than I needed. Hence the extras I mentioned before. Then I found a set of NOS 550 barrels going cheap, so I bought them and had to then source a set of genuine standard pistons and rings, which I did. I now have to decide which set I'll fit, the ceramic coated set need a bore but I can't work on the bike just yet due to health problems so no rush. I may keep the NOS barrels for spares, they'll only go up in value.
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I can find 2 sets of 0.5 oversize rings and 2 genuine 0.5 oversize pistons. However Cruzinimage will be much cheaper, I'm personally not a fan of Cruzinimage as I hear bad things being said of them on the USA site amongst others, especially on ring quality.
Oddly I'm going through the same as you. I have a 500 engine which I'm converting to a 550 set of barrels, I had one set of barrels ceramic coated and then found a mark on the bores that meant I had to consider a rebore. I decided to go 0.5, got new rings and for some reason I ended up with more 0.5 pistons than I needed. Hence the extras I mentioned before. Then I found a set of NOS 550 barrels going cheap, so I bought them and had to then source a set of genuine standard pistons and rings, which I did. I now have to decide which set I'll fit, the ceramic coated set need a bore but I can't work on the bike just yet due to health problems so no rush. I may keep the NOS barrels for spares, they'll only go up in value.
I guess I need some more information. I'll put an existing ring in each bore and measure the gap. I assume that if they are within tolerance, then replacing the pitted piston and the chipped pistons with std pistons and rings is an option? i feel out of my depth here :-)
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If you use a used ring and it's within spec then yes stay standard. Change the pistons though. However you'll normally find it will be out of spec, then you're left with wondering if it's the rings which are worn or the bores or both. Only with a set of new rings can you be certain. I did this test on my NOS barrels and you'd expect them to all be at the bottom of the spec range but in fact they were around the middle. Wasn't best pleased by that but what can you do. If you were local I'd pop round with a NOS set of standard rings and we could see what they measure up at. However check the bores first, with that amount of damage on the pistons I'd expect some on the bores as well. Maybe post some pics of the bores.
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There are several firms selling piston kits, Dave Silvers has 0.25 os kits BUT nearly all the 500 bolcks i have bored did not clean at o.25 and had to go0.5 due to "barreling"
Cruzin only sell 0.5 and 1.0 as does an English firm i have bought from.
I know Trigger used Cruzin and i have done a few 400 recently using their kits, the us problems i have read about all seem to be 350 four and they are VERY critical on bore to piston clearance.
Cruzin piston kits usually arrive within 8 days and i have had uk parcels take longer
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When I opened up my 550 engine I found the piston tops had score marks that look like they have come from a belt sander with 60 grit abrasive. I have to assume that is exactly what it is and that some tosser ‘cleaned’ the pistons on a belt sander!!!??.
Anyway I decided to replace the pistons and after looking around I got these IMD ones which look OK, the company is in the U.K. www.imdpistons.com and were very helpful on the phone, the pistons are made in Taiwan and look good. A lot of pistons are made in Taiwan. The pistons come complete with rings, gudgeon pin and circlips.
I have got standard size as my bores seem ok.
If you do change your pistons, and I would, then you need a full set. If you stick with what you have and just change the damaged pistons then you will need genuine Honda pistons so that the weights match.
You say you are a bit overwhelmed with it at the moment, don’t worry this will just become normal life after about a month🙄
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If you use a used ring and it's within spec then yes stay standard. Change the pistons though. However you'll normally find it will be out of spec, then you're left with wondering if it's the rings which are worn or the bores or both. Only with a set of new rings can you be certain. I did this test on my NOS barrels and you'd expect them to all be at the bottom of the spec range but in fact they were around the middle. Wasn't best pleased by that but what can you do. If you were local I'd pop round with a NOS set of standard rings and we could see what they measure up at. However check the bores first, with that amount of damage on the pistons I'd expect some on the bores as well. Maybe post some pics of the bores.
Here are some pics of the bores. To the touch, they feel smooth, but one cylinder has a slight vertical indentation about an inch long, about halfway down.
I used the second ring from each piston to check the gaps at the top and bottom of each cylinder (since I broke the top ones), which should indicate wear.
- Top 1- 0.55mm, 2 - 0.63mm, 3 - 0.65mm, 4 - 0.35mm
- Bottom 1 - 0.70mm, 2 - 0.75mm, 3 - 0.70mm, 4 - 0.55mm
Looking at the book, these are all outside the standard range of 0.15mm to 0.35mm, assuming I'm reading it correctly.
BTW, Thank you all very much in helping me sort out what to do.
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I would go with a rebore to .5 oversize then you know its right. I have used IMD pistons on a 550 with rebore done by Trigger and all seemed well. I think they do rebores as well, worth asking.
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just had a look and IMD are £167 per set plus P&P also do rebores from £35 per bore.
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I am not sure your readings mean a great deal because it sounds like you used a different ring in each bore, the rings may have different degrees of wear or even gaped slightly different when first used.
At The very top of the bore, top 1 to 3mm, there should be virtually no wear. Use one ring for all bores, take the reading at the top most edge, then about 3 readings down the length of the bore. The variation between the reading at the top and those further down the bore will indicate bore wear. As the same ring is used in each bore an indication of difference between the bores can also be seen.
All that said, having seen the photos of your bores, plus the fact you need new pistons anyway, I would just go for a rebore.
The piston to bore clearance are very small 0005 to 0008 thou as I recall, there is plenty of past posts about this on the site, so Get someone that knows about boring these engines to do the rebore if possible. If not, then tell your machine shop what you want and don’t be dissuaded when they try to tell you the clearance are too small. Check this out further though.
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Update.
I've sent the cylinders off to IMD Pistons, as they do Rebores and supply the pistons, so rather than faffing around, i get a complete service, and a discount on the pistons.
While I'm waiting for their return, I've been cleaning up the cylinder head, have removed the valves for cleaning/lapping, and removed the bottom end from the frame so I can clean and prepare it for painting. I've decided not to strip the paint from the block, but give it a good clean and rub down.
The frame is in good condition with some small rust spots, which I'll rub down and paint. I don't think a full powder coat is needed.
I'm coming across bits and pieces that are missing or broken, and on the whole i'm finding parts, but some things like the seat, grab rail, and front and rear mudguards are almost impossible to find or so expensive it's worth keeping the rusted ones I have!
I'm starting to take apart some of the electronics and wonder how i clean them up. Do i disassemble the connections, clean and reassemble or do i just clean the surfaces? Pic is an example of one i have to do.
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Undo, clean, lubricate, tighten the female side and reconnect all bullets and spades using electrolytic grease or at least vaseline, cable outers use brake cleaner, preferably outside
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Cillit Bang limescale remover cleans the brass bullets and spades up really well. Then do what Bryan says.
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I removed all the individual spade connectors from the plastic plug and cleaned up the terminals. There’s a little barb that prevents the connectors coming out that can be manipulated with a small home made tool. Might not have to go down that road if you use the above method.😜
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Cheap set of dental pics from tool stall at steam, or other, rally
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I'm just preparing to tackle cleaning up my carbs. The outsides aren't too bad, and I quite like the patina on them, so I may well just give them a good clean and leave them at that.
I won't know what the insides are like until I open them up.
I don't have access to a special cleaner, so I was just going to use Carb Cleaner.
My question is: do I need to replace all the jets and parts you get in a rebuild kit, or will a good clean and replacement of the gaskets do?
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If your brass bits are OEM Keihin, thoroughly clean all the brassware, jets, emulsion tubes etc by removing them, then re use. Fit all new Viton O rings (I stock the kits), re use the top gasket.
Carb cleaner is good but make sure you get it in all the hidden passages. Ideally, an ultrasonic cleaner is best (after removing all the internals) then you can get the entire carb body thoroughly clean. But, if all you have is carb cleaner, use that.
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If your brass bits are OEM Keihin, thoroughly clean all the brassware, jets, emulsion tubes etc by removing them, then re use. Fit all new Viton O rings (I stock the kits), re use the top gasket.
Carb cleaner is good but make sure you get it in all the hidden passages. Ideally, an ultrasonic cleaner is best (after removing all the internals) then you can get the entire carb body thoroughly clean. But, if all you have is carb cleaner, use that.
Thank you. Will I be able to tell if the Brass bits are OEM?
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Yes, the jets will have the Keihin logo stamped on them, it's a letter K that almost looks like a star shape.
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If your brass bits are OEM Keihin, thoroughly clean all the brassware, jets, emulsion tubes etc by removing them, then re use. Fit all new Viton O rings (I stock the kits), re use the top gasket.
Carb cleaner is good but make sure you get it in all the hidden passages. Ideally, an ultrasonic cleaner is best (after removing all the internals) then you can get the entire carb body thoroughly clean. But, if all you have is carb cleaner, use that.
What Julie said is good advice, but don't mix up the parts from different carbs. Use a pot or tray for all the parts from each carb.
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Replace the fuel pipe as well, the old one will most likely be going hard and cracking.
Check the needle clips are in the right slot and the jets are the correct size, you never know who's been tampering with them over the years.
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Quick update.
The bike is completely apart now, and I've discovered a few things.
The steering bearings had been upgraded, but the bottom one had failed - see pic. It was fitted with a spacer, but no seal. I've seen videos where its shown that the seal can foul the bearing when torqued down, so it's got me thinking whether I should just go back to ball and cup?
The rear swing arm is rot underneath, so I've ordered a replacement.
The bottom stem yoke, one of the stop posts, has broken off. Do I replace the whole thing or get someone to weld on a new one? Replacement yoke is only £30.
I've been speaking to Hondaman, and with postage being prohibitively expensive from the US I am going to try to make a new fuse box as per his instructions - wish me luck never done anything like that before!
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Looks like the bottom race that goes inside the frame was hammered into place and it broke apart as it was fitted. They didn’t come with a seal back in the day, they do now. Up to you which system you replace it with, I prefer tapers but some people have had problems with fitting them and have gone back to ball bearings.
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I had lots of trouble with the taper bearing, eventually reverting to the original ball race solution. Regarding the bottom yoke, be cautious. They are made of cheese and can be easily bent (misaligned). It is possible to realign them, but it’s also very easy to over-stress them doing so. In fact some on this forum may not recommend re truing, but I’d say it really depends on the amount of misalignment…I managed it successfully. If the original bottom yoke is in good condition and has good alignment, try welding and grinding a new stop as a first resort.
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As Ken mentions in his reply that lower taper has been hit with a hammer and was probably like that from the day it was installed!
Speaking as a 400/4 owner I have attempted to fit tapers twice and both ended in failure as a result of not having enough thread showing on the top nut, 1.5 turns in my opinion is dangerous. I went back to ball bearings, much better and I haven't noticed any difference in handling at the speeds we are allowed to travel at in this country as a result of camera's but mostly due to potholes etc!
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As Ken mentions in his reply that lower taper has been hit with a hammer and was probably like that from the day it was installed!
Speaking as a 400/4 owner I have attempted to fit tapers twice and both ended in failure as a result of not having enough thread showing on the top nut, 1.5 turns in my opinion is dangerous. I went back to ball bearings, much better and I haven't noticed any difference in handling at the speeds we are allowed to travel at in this country as a result of camera's but mostly due to potholes etc!
I'm not planning on doing lots of miles or speeds, so I'm looking for the most cost-effective and quickest way to go.
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In defence of taper roller kits I have found there has been an improvement in the last couple of years. I've had a good experience with Pyramid Parts Kits.
That said I would probably stick with original ball bearings if I have a next time project. My 400 NA Superdream project has been on hold since Wendy's stroke last April. I'm planning to work on the SD again in April/May depending on the weather.👍
Like Ken my own health is only just returning to a point where work on the bike is possible. I've lost a good three and a half stone in weight since last July, My arm muscles have gone in the process so it's a case of the mind is willing but the body less so. Lol
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Had exactly the same experience as Dave fitting a taper roller kit. The beasrings had hte correct internal and external diameters, but the 'stack' was too tall, and barely any thread was poking through to tighten down the castle nuts.
REverted back to a ball bearing kit which had no issues.
Back in the day, I fitted many a taper roller kit, but for whatever reason, the currently available kits do not seem to have the right dimensions in a lot of cases
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I like taper head bearings and feel they are the best so I bought a taper bearing kit for my 550, I had problems fitting it, same as others have said ‘to high not enough thread left at the top’ not protected from elements. I decided original setup had been ok for 50 years so got new bearings and went back to that, everything fits as it should no problems. So my advise, take the easy path.
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My 500 already had a taper roller set fitted by the PO, due to water ingress and some standing there was rust on them so I replaced them with a Pyramid set that were the same dimensions (including height). As has been mentioned the bearings stack height needs to be the same or less than the original bearings to avoid thread loss.
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Qucick Update 1st April
been a while since i gave an update.
The bike is now completely dismantled. Discovered that the swing arm was rot, so purchased second hand one from ebay, same for the steering yoke which had some damage, so i replaced that.
The cylinders have been returned, bored out with new pistons and rings.
All engine casings have been prepped for paint - just need some warmer weather before I tackle that.
The frame and other bits are with the powder coater, and I should have them back in a few weeks.
I'm now systematically going through the boxes, cleaning and repairing where needed. Finding other bits that will need paint, which I'll do myself.
I'm now tackling the wiring harness. The bike probably had electrical problems, as many connections were poor or corroded, so cleaned and replaced where necessary.
My major achievement has been building a new fuse box, with ATC/ATO fuses. Issues with extortionate postal charges from the states made it a no-go for Hondaman, so with his direction, I have built my own. Parts cost about £10, so worth a try! For the eagle-eyed, the fuses are not the final rated ones, just what came with the unit.
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Not forgotten the clutch basket Neil, just been a bit unwell recently.
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Not forgotten the clutch basket Neil, just been a bit unwell recently.
I don't think that's for me. Hope you're on the mend.
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I have done a similar thing, I bought my fuse box from vehicle wiring products, it’s worked out well, I have got it fixed to the electric panel and plugged in to the harness. I now plan to run the electronic ignition through the fourth fuse, it’s an afterthought so will have to do a bit of an alteration to the wiring. I will try to post a photo