When is a motor not worth working on?

[alexdecker]

Hey

Ok, så got this CB550F. It had some top end work done, and it runs fine now. The primary chain is loose and needs to be changed, and contemplating doing a major restoration of the engine.

The old lady has 80000 km on her (yes, that was five zeros). Do we have some sort of guideline as to when the engine is not worth working on anymore? When do you just run out the life of the bike, and when do you continue to restore?

- Alex

[haynes66]

my trusty cx500 did 160,000 before the shaft drive gave up. if it runs, use it

[Sesman]

My only concern would be leaving the chains and tensioners too long and inviting a catastrophic failure.

The big question is what are you prepared to replace when you are in the motor?

I replaced all bearings, bearing shells, seals, chains, rings and tensioners. My valves, guides, cams and cam bearing surfaces and bores were in fantastic condition and only required lapping and honing. I still spent around £700.

I get the satisfaction, but the next owner gets the benefit.

So I guess the answer is run it, but don’t break it.

[Johnwebley]

80k is only 50,000miles ,

Nothing for these motors,

Mine is into the 70k,and running sweetly


Sent from my SM-A750FN using Tapatalk

[Sesman]

I suppose it depends on the type,of miles and the type of owner.

Alex tells us his cam chain is cooked and I’ve read many reports,on this forum of primary drive chains been goosed at 30k and eating into oil galleries?

I wouldn’t know as I’m not expert, but can only report on my engine strip at 17k. Miles. I’d say there was nothing seriously wrong, but the cam chain was deffo at the end of adjustment and the primary drive around 70% worn.

Again, maintenance is the key issue…oil, balance and adjustment. Use, but don’t abuse.

[alexdecker]

I have yet to dive into the bottom end - would start that proces in a few weeks, but if the consensus was that after 50000 miles, they weren't worth repairing anymore, I wouldn't spend my time on it. Money is not really a problem - just doing it for the fun and as a spring project. With that being said, part of the reward is of course still to complete a nice build and get to drive it quite a few miles afterwards.

So I basically asked to make sure that I don't spend my time on a fools errand by taking it apart. I have no idea if anybody has ever been in the bottom end before, or how it looks. I fixed the top end, and both cylinders and pistons were in okay condition for some more milage, but with the slack I saw in the primary chain, I am not sure it has been taken apart. There is no rattle to an extent that I think the chain is digging into the oil gallery. I have a video if the bike idling here - maybe you guys can hear something I can't?

https://youtu.be/3XW8BiG1dDk

- Alex

[Oddjob]

Both of mine are in 6 figures now, yours is barely run in by comparison.

The one I'm doing now has 147000+ miles on it, my K reg was at 268000 last time I rode it, BIL is still riding it about after doing a restoration last year. If I was still young I'd be trying for 7 figures but we don't have the weather at my age to do it.

[alexdecker]

Thank you all for your answers! I have gained hope for a complete restoration, and will go into the deep (bottom) end on this bike then

[Bryanj]

Primary chain(Kawasaki identical) £70
Cam chain                                           £30
Cam chain tens blade                       £35
Cam chain tens cushion                  £30
Gasket kit                                           £70
Seal kit                                                £30

I would be surprised if you needed shells or bearings at all and the 550 has more clearance between primary chain and oil gallery than 500 so does not need as frequent replacement.

Its when you need shells and transmission bearings it gets uber expensive

[Sesman]

Gasket goo, oil, bearing guard, paint……

[Sesman]

Primary Drive rubbers, non pattern tensioner. Agree about the shells. I replaced mine just cos I got them at a really good price and felt is was ‘worthy’.

[Bryanj]

Primary cush rubbers maybe 8x£8 you dont need tensioner if its working just blade. The 550's i done dont seem to hammer the cush rubbers as much,maybe cos the chain dont hammer the case as much, goo is a stock item, oil and filter are sevice items not part of rebuild tp me, i never blast and paint so didnt think of them and as it doesnt apear to be a full resto why do it, clean is good

[Sesman]

  Aye, good points.   

[alexdecker]

Okay, made a list gathering the items listed. This is helpful.

Primary Chain
Cam chain
Cam chain tensioner blade
Cam chain tensioner cushion
Gasket Kit
Seal Kit
Primary Drive Cushion Rubbers
Non Pattern Tensioner
Bearing Guard

Don't know about the last to items though - bearing guard for where? And never heard about non pattern tensioner. Is that the cam chain tensioner, or?

- Alex

[Sesman]

Hi, Alex. Apologies, what I meant to say was “genuine tensioner blade” blade, which is about twice the price of a pattern part. You shouldn’t need a tensioner assembly unless it’s damaged or has a weak action.

Don’t underestimate the accumulative cost of hondabond, assembly lube, paint, paint prep such as sodablast and other decorative and service items.