Honda-SOHC
General => New Member Introductions => Topic started by: Johny Boy on September 01, 2023, 02:05:12 PM
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Hi there, I have been a member for a few weeks now, lots of useful info already absorbed, but first post today.
I'm John and I live in Red Lodge, Suffolk
I recently bought a very tatty but cheap CB550 K3 from Ebay, obviously without seeing it.
It is similar to the one I had when I was 21 (Some 33 years ago!)
My plan is a full strip and resto, but I'm afraid not back to full original (Sorry), Matt black with newer lights etc.
I am keeping a record of the Strip / Resto, attached here and I am sure I will be looking for lots of advice / parts when I actually get to the re-build stage.
My first question, given that the front fork tubes are bent, is does anybody have any experience of these TNK Made in Italy ones?
I have looked around at second hand ones, but they all seem to be rather rusty and I'm thinking that new ones might be better?
Any other options welcome.
Thanks in advance for any replies / advice
John
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Depends on how bent they are.
Companies like Philpotts and Dynasurf an straighten them out if they are not too bent and the metal isn't creased, they'll then hard chrome them, which as the name implies is a LOT harder than the standard chrome and is almost impossible to chip in use, all for less than £200. Rust isn't a problem with the process.
Original is better than aftermarket in almost every instance.
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Thanks Oddjob, they have about a 3 to 4mm bow in them, I'll send them some photos and see what they think, because other than being bent they are in quite good condition, no creases in them [attachimg=1]
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Welcome to the forum.
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Welcome here Johny Boy
You're in the right place to meet expert advice, good luck with your restoration.
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Philpotts definately and send the top nuts as well.
Biggest problem with K3 is getting carbs to run right as they hate being stood and if you want anything other than standard airbox you are in for grief
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Hi Johny Boy, welcome to the forum. This is for sure is the right place for loads of very valuable help. Yes agree with Bryan, am still got a bit of a flat spot at 4000rpm with my K3, although sorted cold starting issue with slightly increased pilot jets. Next move clean up old main jets and needles and take out the Keyster replacements. (Winter job) Good luck!
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A long time ago I had some forks from my Suzi GS750 straightened/unbent and I'm sure they were bent more than that. Chrome was good so it was merely a 'press' job. Hope yours turn out OK and they don't need rechroming.
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Welcome to the forum! I've used philpotts - they give a great service including a pick up service and as Bryan says, send the top nuts as they re-chrome them for free
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Welcome I used Philpotts for my 500 forks that were badly rusted
- they came back looking like new. IIRC the cost was £220 incl VAT,collection & return service in 2022.
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Thanks everyone, I have emailed Philpots with pictures, I have heard that putting electronic ignition on can help with the flat spot issues? Something I am planning on doing as points always seem to cause issues on old motors
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Thanks everyone, I have emailed Philpots with pictures, I have heard that putting electronic ignition on can help with the flat spot issues? Something I am planning on doing as points always seem to cause issues on old motors
Usually best to get the bike running spot on with the points before changing to electronic ignition. It may be a fuel issue so best to resolve the problem 1st. All our CB SOHC/4' still run on OEM points without issue. But I appreciate some owners much prefer electronic ignition.
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Thanks everyone, I have emailed Philpots with pictures, I have heard that putting electronic ignition on can help with the flat spot issues? Something I am planning on doing as points always seem to cause issues on old motors
I have electronic ignition on mine! Still flat spot!
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Thanks everyone, I have emailed Philpots with pictures, I have heard that putting electronic ignition on can help with the flat spot issues? Something I am planning on doing as points always seem to cause issues on old motors
I have electronic ignition on mine! Still flat spot!
That is disapointing, still it will be a few months before mine is on the road, given the carbs a good degreasing and planning on putting all the parts through an ultrasonic tank before I re-assemble.
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PD carbs on the K3 are notorious for being a pain in the arse.
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Consensus on here is to always use original brassware unless you are changing jetting.
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Consensus on here is to always use original brassware unless you are changing jetting.
Thanks Johnny, I am hoping to, not taken them apart yet, the barrels do look to have some wear on them, do you think they are OK to re-use?
[attachimg=1]
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Thanks everyone, I have emailed Philpots with pictures, I have heard that putting electronic ignition on can help with the flat spot issues? Something I am planning on doing as points always seem to cause issues on old motors
I have electronic ignition on mine! Still flat spot!
That is disapointing, still it will be a few months before mine is on the road, given the carbs a good degreasing and planning on putting all the parts through an ultrasonic tank before I re-assemble.
You might need to poke some jets out with a wire after an Ultrasound bath then give them some more Ultrasound depending on the level of dirt.
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Those don't look like PD carbs to me, more like 069A carbs off a 550 for instance.
Do they have a choke lever on number 1 carb? the PD carbs have a cable operated choke.
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Hi, it is a 550 and yes lever choke
[attachimg=1]
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Those are 550F carbs(or 500), have you the blanking screws for vacuum tackoff point on the manifolds that bolt to head?
The carbs you have are way easier to work with by the way
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Hi Bryan. not exactly sure what you mean, picture below is the of the manifolds
[attachimg=1]
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Welcome to the Mad world of the SOHC. Looks like you have the wrong manifolds fitted for those carbs ;)
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You need this type of inlet manifolds for the carbs you have .
[attachimg=1]
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Thanks Trigger, now the vacuum take off comment above makes sense, I'll have to add a new set of manifolds to the ever growing shopping list....
Still at least the Carbs will hopefully be less hassle than the PD ones! Small wins
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To use that type of carbs, you will also need the correct air box to carb rubbers. Your choke lever is bent and will need a little straightening up ;)
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And 500 or 550 EXCEPT K3 manifolds will do and the rubbers for your carbs to airbox are available pattern
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Look at number 4 carb, on the flange where the carb bolts to the bracket see if you can read and post the numbers etc stamped into the alloy.
I knew the carbs were wrong as you said you had a K3 and that has PD carbs which everyone keeps saying are trouble, which TBH they are. However there are at least 4 different variants of those carbs you've pictured so knowing what the numbers are tells us what bike they were originally fitted, the jets etc are different.
The 550F1/2 for instance uses 069A carbs, generally.
The 500 uses the exact same looking carbs but those are normally 627B for the UK, different ones for Europe for instance, 022A if I remember correctly.
I may have a spare pair of carb manifolds lying around with the vac gauge outlet, the K3 had the outlets on the carbs hence why there are none on the manifold.
If it was running before it's likely the previous owner has already changed the airbox to carb rubbers as the K3 type are too long.
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Hi Oddjob, soory for the 6month delay in replying, got into the strip down and parked the engine and carbs.
Happy new year to everyone. Got my forks straightenged and rechromed though - Philpotts, super job.
I have looked and they are 069A's - which I have now fully stripped down, could you suggest a good rebuild kit?
I think I am going to have to replace the Thottle Slides as well as they are very worn, you can feel the wear easily with your fingers.
[attachimg=2]
Also I have managed to snap one of the pilot jets off in the body, wierdly its not the thread that has snapped but the cross drilled tube at the end, I'm guessing it must have been stuck to the body, these were in a right state inside, soft and solidified white gunk everywhere.
Anybody got any bright ideas for getting it out? ive tried banging a straight pick into it, it seems to lock in the bore but won't hold on when pulled.
I have sprayed copious amounts of WD40 and Carb Cleaner in there.
[attachimg=1]
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Try to find a tap which will run down the bore in it (or drill out very slightly to take a tap either metric or BA) and tap some kind of thread. then put a metal sleeve slightly larger OD over it and screw a tapped bar/screw into it with a washer underneath the head in case of screw or nut if it's threaded bar you used. Then try to extract it. You could heat it very slightly with a creme-brulee type gas mini torch but be careful ... that alloy they used does melt quite easily.
Another method it to get a hex Torx type screwdriver bit that is slightly larger diameter than the hole in the tube. Press into the the stuck tube (ie tap in with a little hammer) and then heat slightly as above and try to twist the bit and pull out the stuck tube.
Another method is to file a piece of bar/screwdriver so that it looks like the tang of a file (i.e square section but slightly tapered) so that when you tap it into the hole in the brass tube the corners bite into the walls of the tube. Again use heat as above.
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Will be difficult getting just slides unless Trigger has some spares, you will probably end with another set of carbs and use the best of what you get.
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I have a few spare slides, however they look identical to the 500 ones so you need to ensure you're fitting the correct type for the 069a carbs, the needles are slightly different from the 500 IIRC.
As for the broken jet, what carb number is it broken off in? I have some spare 069A carb bodies but not all of them, I'm betting the one you want will be the one I haven't got. I seem to recall I have No2 and No4 but could be wrong. I'll also have a spare choke lever if that doesn't straighten out very well.
069A carbs will use 98 main jets and 38 idle or slow jets. I may have a spare idle jet, not 100% sure.
Check for markings on the slides, they are numbered to identify them. Also look inside, at the bottom there is some more writing IIRC. Or it may be where the needle comes out.
I'd try a small drill in the jet, slow speed and it may jam, sometimes when you reverse the drill it comes out with it.
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Thanks for those ideas, the only trouble is the bore is just over 1mm diameter and the OD is 1.8mm
Don't have any taps that samll, even my smallest stud remover is way too big, I think I am going to try the drill option.
1.5mm drill, hopefully it will catch, if not the wall will be virtually gone, hopefully no damage to the body, I will turn up a centering bush first
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I have a few spare slides, however they look identical to the 500 ones so you need to ensure you're fitting the correct type for the 069a carbs, the needles are slightly different from the 500 IIRC.
As for the broken jet, what carb number is it broken off in? I have some spare 069A carb bodies but not all of them, I'm betting the one you want will be the one I haven't got. I seem to recall I have No2 and No4 but could be wrong. I'll also have a spare choke lever if that doesn't straighten out very well.
069A carbs will use 98 main jets and 38 idle or slow jets. I may have a spare idle jet, not 100% sure.
Check for markings on the slides, they are numbered to identify them. Also look inside, at the bottom there is some more writing IIRC. Or it may be where the needle comes out.
I'd try a small drill in the jet, slow speed and it may jam, sometimes when you reverse the drill it comes out with it.
Thanks for this, the slides have 2 markings a "Star 2.5" and "103" and the body is No4, As I said above I am going to turn up a drill bush tomorrow and put a 1.5mm drill up it, it will either grab or leave a 0.15mm wall full of holes, hopefully I can pick / ultrasonic any bits out.
I will update tomorrow, John
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Pleased to report a 2mm drill is the perfect removal tool.
Now onto the Soda Blasting