Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Orcade-Ian on January 02, 2023, 06:22:48 PM
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Hi folks,
Been mulling over the method of carb fitment on this 550 - the 350 and 400's are tight for space but I think the 550 is even worse. I have new manifold and airbox rubbers but don't like the idea of distorting them considerably to fight the bank back in. Yes, the air filter box is free, giving a bit more wiggle room. I know one or two folk have replaced the studs with bolts but that would be too visible. I'm considering removing the studs and silver soldering the nuts on and then re-plating them, so that they look right but act like bolts. I would probably remove about 1mm from the head end of the studs so there was no fear of them binding up. I would always prefer stud fixing so as not to wear the threads in the head but they don't come on and off that regularly (he said!)
Any thoughts?
Ian
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Seems a lot of work for something that can be fitted in the time it take to make a cuppa ::)
I must of fitted hundreds of carbs over the years. To make life easier :
Fit the clamps after you have the manifold rubbers on. Put a smear of red rubber grease , on the air box to carb rubbers , drop the manifold rubbers in boiling water, take them out after a couple of minutes, (start on number 2&3 ) wipe dry, a spray of back to black silicone and they fall on.
Replace the two m6 bolts in the air box mounts and feed the clamps round the rubbers, place a smear of copper grease on the JIS screws and tighten up ;)
Always harder with old hard rubbers :o
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I've found that the easiest way to get carbs on and off is to drop the engine forward, that's assuming you've got the engine loose in the frame. So after fitting the engine just fit the back lower bolt and the back upper bolt, fit some frame protection around the frame tubes, like copper pipe insulation for instance or rags etc. Fit a small jack under the engine just to take the weight, remove the upper rear bolt and the engine will tilt forward, fit the carbs now and you'll find they go in easily and with all the rubbers in place. You can also remove the airbox mounting bolts and pull that back a little if you want some extra room.
Don't get the comment about bolts being too visible, I intend to replace my studs with bolts this time round, I'll be using the later 8mm headed bolts that Honda are still using. TBH they should be less obvious than the larger 10mm nuts it currently uses. Without the studs the carbs should slide in no problem. It's whether the bolts are easy to get at that may be a problem.
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Thanks Graham,
I might give that method of yours a try first, it obviously works for you. The new rubbers are DS aftermarket ones, I hope that doesn't make it more difficult. Ken, I was meaning the bolt 'bodge' would be obvious - visible is probably not the right word. I was attempting to keep it looking standard and not modified - yeah, I should get out more!
Ian
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On my 400 I found it pretty easy to fit the carbs back in place when the rear wheel, mudguard & battery box were not in place working backwards from the carbs it was easy to fit things without the struggle of a tight gap or distortion. The battery box on the 400 comes out easily with the plastic section of the rear mudguard out.
I don't know if that is the same amount of time involved as tipping the engine or more.
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IMO Ian far too much emphasis is placed on not modified these days. There isn’t a single bike on the road of our age that hasn’t been modified in some way. Be that by fitting LED bulbs or by fitting sintered pads for instance.
If the mod makes the bike better or easier to work on why let a really small thing like “people may spot it” deter you. Getting carbs in on the 500/550 can be a nightmare of a job, with the advent of modern fuels etc the chances of leakage greatly increases, meaning you may have to remove them in order to fix little problems, anything which helps you do that has to be a good thing.
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Ted, having done quite a few 400's and a couple of 350's which are pretty much identical - fitting space wise, the 550 is a whole lot tighter. I obviously respect Graham's view - he and many others have done so many, it becomes second nature but as a 550 Virgin, I just wanted to share my thoughts on the process.
Ken, I'm certainly not averse to modifying something to make even a small aspect better and will almost certainly do this stud/bolt mod. When I was serving my apprenticeship an older, wiser guy said to me 'When working on any machinery or equipment, always make it easier for the next guy to do his job - it might be you!'
Ian
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Seeing as you can silver solder and BZP at home Ian,not a long job to do and so it sounded like a good idea to me ... easier to fit and looks original.
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Ted, having done quite a few 400's and a couple of 350's which are pretty much identical - fitting space wise, the 550 is a whole lot tighter. I obviously respect Graham's view - he and many others have done so many, it becomes second nature but as a 550 Virgin, I just wanted to share my thoughts on the process.
Ken, I'm certainly not averse to modifying something to make even a small aspect better and will almost certainly do this stud/bolt mod. When I was serving my apprenticeship an older, wiser guy said to me 'When working on any machinery or equipment, always make it easier for the next guy to do his job - it might be you!'
Ian
Ian I was just sharing my limited experience on a single 400 that I took the carbs off a few times - having never tilted an engine like Graham I have no idea how easy or difficult that might be I just have this vision that it might involve removing the silencer that might be rusted on etc.
I would never presume to know better than Graham, Bryan Ken or anyone else here for that matter.
Just shared my method fwiw not trying to out do - anyone sorry if that is how I came across.
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Thanks Ash,
Head - nail, nail - head! :)
Ian
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Ted,
No offence my friend - this forum is all about learning from each other and sharing good and bad. I'm only doing the necessary to this 'James 550'. (did they ever make a 550? My Dad had a 98cc) I'm reluctant to remove the exhaust and other bits at this stage just to make refitting the carbs easier!
I've also got a set of the correct 069 carbs in the pipeline to do the 'bling-over' on, so these will have to come out again - so I will be that 'next guy'. Although I will leave the air plenum and filter box off just to run it in the workshop.
Ian
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All good methods and experience to draw from there.
On topic of original posting, I can't see any particular problem associated with going that way. Unsure about rating silver solder but easily check with a sample and tourqe wrench to assess if you feel it has enough security. Obviously if it comes loose in this scenario it particularly low risk anyway.
Understand about balance of thread use if they were to be taken off frequently, but hopefully with good recommissioned set that would be avoided.
On that axis though, you could turn a very simple venturi device (or make one from plastic plumbing fittings) to fix engine side of carb body, then using compressed air to draw vacuum, test the jet circuits to ensure flow from idle, main etc without having to run them to find out if they are impaired.
Sight tube on float bowl and you could judge level drop from single fill to give idea of flow. Or clear plastic connection to carb and shine a torch through while running to see fuel atomisation.
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Only problem i can think of is bloody O rings falling out! Evostick anybody?
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I've learned to do all carb maintenance with carbs in situ. I can do it blindfolded. Undo the floatbowls is all what is needed. It helps to know what's in there. When you're at it, replace those 16 crossheads by allen bolts.
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I seem to recall the manifolds have small restrictions in the groove which grip the o-ring Bryan so they don't come out. Could be wrong but for some reason it sounds right.
I'll try the method and report back on whether it works or not, when I eventually build this bike that is.
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So does the cbx rocker cover but you still need the evostick
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Yeah but on that there was loads of stuff that caught the gasket as you were trying to refit the box, plus it was bloody tight getting it back in place, not a great deal at the back of a 500/550 head to do that especially if there are no studs anymore. There's only the top bolt for the tensioner that can catch it I reckon.
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.........and you really HAVE to tilt that bleedin' great lump forwards to get the carbs out, good job there's no frame tubes in the way.
K2-K6 - I experimented with a 'back pressure' system for setting the slides equal - I didn't persevere as it was no better (or worse) than the small drill method prior to Vac sync.
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Bryan, I used a couple of dabs of blue Hylomar to keep the o rings in the elbows on my GL1000 - I think you supplied one of those to replace my cracked one?
Ian
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For Delta rider,
I've done 350/4 float bowls like that but these carbs needed a full seeing to in the first instance - I knew they were 627's (CB500) so had to see what jetting was there - as it turned out they were 38/98, so OK for 550F1.
Ian
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If you don't want to go to the bother of soldering and plating I would have thought a drop of Loctite 270 would do what your initial requirement
was.
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Thanks for that alternative - I'm sure you are right. I always seem to gravitate towards silver soldering - I have plenty and will never get to the bottom of the tub of powdered flux I bought 30 years ago! It's also very satisfying to see the material suddenly flow through a joint if everything is clean and the temperature right. I also sometimes forget that modern products are often simpler and in many cases better.
Ian
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Thanks for that alternative - I'm sure you are right. I always seem to gravitate towards silver soldering - I have plenty and will never get to the bottom of the tub of powdered flux I bought 30 years ago! It's also very satisfying to see the material suddenly flow through a joint if everything is clean and the temperature right. I also sometimes forget that modern products are often simpler and in many cases better.
Ian
Just bought bought a pulsed MIG welder and silicon bronze reel of wire to have a go at it ... also a Furick 'Jazzy' cup setup to have a got at Si bronze TIG ... both using pure Argon ... no flux. Never to old to learn y'know ;D
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That sounds like a great piece of kit Ash, especially if it can be used for TIG too. I still have a Portopack set with Oxy/Acet, so always tend to go for gas welding/brazing/just getting things bloody hot! I don't use it for gas-axeing, it uses far too much gas, so just take big stuff to the smiddy. We have a stockist up here for Hobby Weld gases - no rental charges. Might have to ask Gordon about that kit - is there a brand name?
Ian
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That sounds like a great piece of kit Ash, especially if it can be used for TIG too. I still have a Portopack set with Oxy/Acet, so always tend to go for gas welding/brazing/just getting things bloody hot! I don't use it for gas-axeing, it uses far too much gas, so just take big stuff to the smiddy. We have a stockist up here for Hobby Weld gases - no rental charges. Might have to ask Gordon about that kit - is there a brand name?
Ian
See below some videos to watch Ian. All USA ones but quite informative.
I mainly need it to make repairs to exhausts and tanks etc but on some parts I use silver solder brazing with a MAP gas torch. Oxy/Acet would be nice but the cost of the hire of even Portopak doesn't really warrant the constant outlay for me. I decided during lock-down to try to do as much myself as possible because you can get p*ssed around so much taking stuff to the 'experts' ..One thing I did was buy myself a small Devilbiss spray gun and air-fed mask to paint my metallic and solid colour bikes. The cost of pro-paint doesn't really warrant the expense on smaller bikes and I hate posting stuff like painted items etc so the time/milage to take stuff back and forth to people also adds up. I am never gong to be an expert at it but quite pleased and satisfied with the results so far. Plus the time scales of pro's always seems to take twice as long as quoted .. I had to wait 2 years for my CD125 to be candy painted in the UK and it ended up costing me £1,200. Menno in Germany was great though but sadly #@%$ has put a stop to that.
So last year I decided to have a go at TIG/MIG silicon bronze brazing to recover chromed items and tanks and panels etc and again invested in some fairly decent kit. I managed to get a really cheap source of pure argon gas and no bottle rental (full size bottle). I find that if you invest in decent kit, then if you get to the stage where you don't use it any more, you can get a decent resale .. Devilbiss/SATA spray guns are a prime example.
https://www.youtube.com/watch?v=mTw1-yag3IY
https://www.youtube.com/watch?v=sUiQfupEwOk
https://www.youtube.com/watch?v=fvR2q-NuZB0
https://www.youtube.com/watch?v=wPI_XNCrES8&t=361s
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Thanks Ash for the clip links - I'll enjoy those when Christine is watching stuff on the 'idiots lantern'.
I also use Mapp gas in a really good Rothenberger torch but for me, nothing beats the fine control of a number 2 nozzle in my SIF torch. I fully agree with you on buying good quality equipment - the old 'buy cheap, buy twice' adage. I think many folk of our age came through a golden age where we can afford to do that - many are not that fortunate. BTW I don't have rented BOC cylinders any more for the same reason.
On the subject of paint re-finishing UPOL products take some beating - their No1 'smooth and easy' filler is fantastic and their range of aerosols - etch, high build and satin black are great for small stuff. These days I tend to do all the donkey work of filling tanks and panels, then get a mate to hit them with 2 pack primer for me to guide coat and block down and then get him to add the final coats and lacquer.
Ian