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[Oddjob]

Shame you’re in Kent Neil, miles away from me near Manchester. I’d have been happy to pop over and fix the problem for you.

One thing I think I should mention, just in case. I remember you having a problem getting the cam chain onto the sprocket. Unless it’s a new chain you can normally do that with fingers only. A new chain tends to need a little help with some leverage. The reason you had a problem is almost certainly because you didn’t get the tensioner blade to retract enough. That puts pressure on the chain and causes you to suffer because it’s under tension already. The other mistake is people try and fit the tensioner after they have lowered the barrels, then you find getting the adjuster bolt through its hole in the barrels whilst also making sure the bottom part is engaged in its retainer slot in the lower crankcase means one of 2 things happen. You bend the tensioner at its lower end or you miss the retaining slot altogether. You don’t spot that unless you know it’s likely to happen and you’re so relieved it’s finally fitted you don’t think to check. That now means the tensioner is rubbing against the primary chain, lots of little pieces of metal slowly being ground off and going into the oil. Not good.
The foolproof way of avoiding both problems is to stop lowering the barrels around 2” above the gasket. Then fit the tensioner, it will now fit straight very easily. Get the blade and push it back hard after releasing the locknut. As soon as it bottoms tighten the locknut. Easy once you know how. Don’t fit the upper bolt until you’ve fitted the sprocket and then release the locknut. Leave it loose and then try and align the top bolt hole. Sometimes it refuses to line up and you need the tensioner loose in order to get it to line up. If you need to get the tensioner blade to fully retract whilst the heads still on, just release the locknut, slacken off the top bolt a little and use a big flat bladed screwdriver and lever it back, then lock it off.

If you’re worried you’ve missed the retainer slot in the lower crankcase you can check by removing the sump and looking up, you can see if it’s missed or not.

[Neilw]

So the jury is in, and it's not good news.

All of the valves are bent. I had to straighten them slightly to get them out by applying horizontal pressure at the top of each one.

What are my options now? I don't know the condition of the valve guides, and I don't know how to check.

Feeling gutted tbh.

[Bryanj]

Easiest is a used head complete with valves, also cheapest way to get a full set of valves, as to guidessee if any have broken tops

[Neilw]

Easiest is a used head complete with valves, also cheapest way to get a full set of valves, as to guidessee if any have broken tops

Theres this one on Ebay?  https://www.ebay.co.uk/itm/257610142722?_skw=cb500+550+cyclinder+head&itmmeta=01KZ68WP5D8CHZCAXHY5M53BY9&hash=item3bfac2d402:g:hOsAAeSw~klqTKGy&itmprp=enc%3AAQALAAABAGfYFPkwiKCW4ZNSs2u11xBs7J5UtyIjAPmqD9%2BgdFSqt%2B2zA%2FruhpU1522RFoFTen5%2FPPInSnLhTEC980dIuEnLY%2BT%2FFvnvWT9mvdF0R1N1e1HmmZ%2BPXIIBdQ3d9EztOWqStND3oe3sbvXSLIrqwjwx2mz8a507G6tI3ScRvuuT1j307Mcc7%2FYCpZs95kgfrHoUSzRlZXubCNRdhvRfaUGmV6Q5wEs%2F8tBMp4zE6go0jTNztdaqI63v2nv116DtL%2B%2BlIL39ASigIZLmqFQXXgln0Bsu0kjiCzZLJEAlimC8AGvsKFwW%2BaEuVLLRVVoLVFrBSb3ASCHEm5zt2eCUI6I%3D%7Ctkp%3ABk9SR-Tj8sj5Zw

[Oddjob]

Dirty and will need dismantling to clean it all out but journals look ok. Your decision but I’d check your existing head first for guide damage. Someone on here is bound to have some spare valves, I had hundreds of them at one time.

[Neilw]

Dirty and will need dismantling to clean it all out but journals look ok. Your decision but I’d check your existing head first for guide damage. Someone on here is bound to have some spare valves, I had hundreds of them at one time.

Ok, so each of the valve guides is cracked at the top, which means replacement - and that is not a diy job from what i can see. So it's either a replacement head with guides and valves that are hopefully ok, or find someone to rebuild the head. :-(

[Oddjob]

Yeah that’s toast. Skilled job to replace the guides, you need to recut the seats after as well. Much cheaper to find another head.

[Neilw]

Yeah that’s toast. Skilled job to replace the guides, you need to recut the seats after as well. Much cheaper to find another head.

Yep, pretty much what I thought - I'm looking for a head atm, and also emailed a company that does rebuilds to see what they would charge. Will decide in the next day or two.

[Oddjob]

A rough guide to parts prices. A guide is approx £33 each and a valve around £17. Times 8 and it gets expensive real quick.

[Otis]

Just thinking out loud!

Neil has done what I would have done and had a go so fairplay to him for doing this. Mistakes will be made and I have made a few in my time but that's how we learn if that is our inclination.

It's easy to "do up" a vintage bike with your cheque book but that's not why forums like this exist. I wish I could offer more in the way of knowledge but I am "a Neil" and willing to have a go and learn. It obviously helps if one has a competent local friend but for many of us the guidance offered by this forum is all we can hope for and I appreciate very much the kind and thoughtful people who are happy to pass on their knowledge in such an altruistic way.

[Oddjob]

TBH Otis the damage caused means it wasn’t the way the camcover was fitted. As an ex Honda mechanic I’ve seen more than my fair share of “I have no idea how that happened “ mistakes. It’s not the first time it’s happened and it’s certain to happen again. As you say it’s how we learn. It’s such a shame it’s happened and it’s going to cost a bit to correct.

[Otis]

TBH Otis the damage caused means it wasn’t the way the camcover was fitted. As an ex Honnda mechanic I’ve seen more than my fair share of “I have no idea how that happened “ mistakes. It’s not the first time it’s happened and it’s certain to happen again. As you say it’s how we learn. It’s such a shame it’s happened and it’s going to cost a bit to correct.

But you do not gloat and that makes you special. Enthusiasts come from all walks of life and if I had the knowledge and where with all I would help everyone. In this instance it will cost a bit to fix but what a lesson to have learned. At some time in the future Neil's experience will help another newcomer and that is how the cycle continues.

[Oddjob]

I never gloat. The object is to teach others. Hence some of my lengthy posts. In time I’ll pass on and all my experience and knowledge will be lost. I feel it’s my obligation to pass on as much of that as humanly possible. I’ve known mechanics who refused to divulge secrets, they hoarded information like it was money. Or worse they’d mislead you, which is inexcusable.

A lot of the tricks commonly quoted on this forum originally came from me, I had a habit of thinking outside the box and coming up with novel solutions. If I didn’t tell anyone else they’d be lost when I pass on. That helps no one.

I have a cb1300 and on that forum I constantly pass on what I’ve learned, I even offer a shim swap service. I feel it’s the least I can do. I was very lucky to work in the trade, the amount of bikes I got to ride was unbelievable. A turbo charged GS1000 was a good one, popping a wheelie at 100mph was interesting.

[Bryanj]

I agree with Ken and pass on what i was told by Honda travelling techs back in the day

[Johnwebley]

I think this forum and members are a community and also very helpful

Advise is freely given, as is assistance



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