SOHC.co.uk Forums > CB500/550
CB550K - engine rebuild (partial or full)
Bryanj:
Big thing is that the majour part of the work is the time and gaskets/seals to remove and strip the engine, in this case the engine is already totaly stripped so the cost of the chain on top(if you use the Kawasaki one) is minimal.
K2-K6:
A more philosophical question for Erny;-
If you don't verify the cush drive in rear wheel is ok (thinking in regards to gear change quality) and then try the bike to assess the affect it may have, then if you take the engine apart and the gearbox all appears ok, what would you do?
Put it back together without finding "the" fault, or change components at random.
Also for idle quality and smoothness, I'd set the carbs with the "compression weak" cylinder at less vacuum than the other three to listen and assess if it gives a noticeable change.
I just feel that would give a clearer picture and more knowledge to work from if you determine to strip it later.
Erny:
After longer time (I had to find energy to start it ::)) update
Issue No1 (camsshaft/rocker arm) (see my first post for details)
Today I removed valve/cam cover to check IN#1 rocker
What I found surprised me (!?)
- IN rocker arm #1 has uneven wear (arm was touching cam only partially), at least half part of contact surface is not showing any wear at all. Seems issue is present since new bike >:(
- Cam IN#1 lobe shows strong wear (pitting incl) where arm was riding. Rest of contact surface does not show any wear
- Deeper inspection revealed issue comes from worn outside rocker arm shaft hole! Hard to believe but yes...
- Comparing how "deep" are shafts for IN#1 and othher shafts (EX#1, IN#4, EX#4) "buried" in valve cover, I found IN#1 is approx 2mm "deeper". Route cause comes from IN#2 shaft too "deep" and consequently IN#1 shaft too deep too that finally meant too narrow seat.
Shafts are all OK otherwise (forgot to take pics), incl IN#1. There does not look to be any issue with engine lubrication, all other cam lobes, cam bearings, rocker arms shows minimal wear I think (see pics).
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My conclusion is that issue is present practically from new bike, camshart to be repaired/replaced, rocker arm to be replaced, valve cover to be replaced, ideally with new improved type
Issue No2 (identified in previous posts here are probably worn primary chain)
I removed oil pan, see video of primary chain. Looks worn too much or not?
https://youtu.be/a1k28x_15lQ
Now, question to experts here:
- I assume cam lobe shall be repairable (hardwelding, grinding), but when I have it open, I'm thinking about alternative cam (something like Web Cam 358a or cam from CB650?) - what's your view on these cams and their effect on riding? Repair of my cam won't be for free anyway (if I find somebody to do the job).
- how to inspect cam chain and tensioner properly, having removed valve cover? Or, do I need to remove head/cyls too?
This will drive my next steps - if I'll continue stripping or "just" fix cam/rocker issue.
Erny:
remaining pics
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Bryanj:
The modified cover didnt come in til 77 and i see no reason the original cover could not have a thinwall bush fitted, wear happens when the shaft rotates a "quick" fix is to put an O ring in the holefot the pin on theouter cap to trap and stop the shaft rotating
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