Should I change my timing chain?

[Aedan Graves]

I'm about to do rebuild my top end, new rings and gasket because I noticed I'm burning oil and leaking a bit of oil at the head gasket. Now I haven't had issues with it, but I thought I might change the cam chain while I'm in there as preventative maintenance but I'm having a hard time finding a replacement. So now I'm wondering if it's even worth replacing.

Is the timing chain a common point of failure? Would I be better off just replacing the tensioner? Or should I just not touch it at all?

Also if anyone knows about anything else I should look/replace while I have the head/bores off that'd be awesome

Thanks

 

[Aedan Graves]

bump

 

[xschris]

Look by oem part number. Yamaha used the same chain in some 4-wheelers also. Still lots of them around and from Yamaha also I do believe.

 

[Arclight88]

Does the engine have more than 30000 miles? If not, and if there is no noticeable wear its probably fine. I have rebuilt two xs400 motors, but with under 25K miles. Both burned oil prior to rebuild, and both stopped burning oil with a valve lap job and new rings. The timing chain install requires a crank shaft removal, or a split chain installation (not recommended anywhere I've seen). So, I would opt for keeping that original unless a high miler.

 

[Aedan Graves]

Does the engine have more than 30000 miles? If not, and if there is no noticeable wear its probably fine. I have rebuilt two xs400 motors, but with under 25K miles. Both burned oil prior to rebuild, and both stopped burning oil with a valve lap job and new rings. The timing chain install requires a crank shaft removal, or a split chain installation (not recommended anywhere I've seen). So, I would opt for keeping that original unless a high miler.

Wonderful, exactly the info I was looking for. Is a valve lapping necessary to fix the oil burning or is it just to revive compression? It's getting pretty cold here in New England and I want to make it a relatively quick ring and gasket swap spending as few days out in the shed as possible but if you really recommend I do the valves too I will.

Thanks again for the info I appreciate it

 

[xschris]

If you have it a part replace and fix as much as you can while you have it like that. Seals gaskets honing as much as you can. Being an old bike it’s best to get it done now. You don’t want to have to take it apart and have to do it again.