Cam Chain Tensioners

[jwill7]

Hey fellas,
I've been tearing into my 78 KZ400 motor the last few weeks to try and bring some life back into my bike. During the teardown I noticed that my cam chain tensioner had stress cranks along it and had started to chip apart. Seeing as these are no longer being produced, i've tried to source some sort of replacement / fix. This seems to be a fairly common issue.

What have you guys done in order to fix this issue? Does anyone know the name of a plastic material that can stand the heat and wear stresses of a motor?

Cheers,

Jared

[Guest]

The early tensioners were shit all the way up into the early 90's, I'd suggest a stepped type, with the flat end known as the second gen type, avoid the mushroom type of end though...every cam tensioner, I have ran across from Kawasaki retro fits from the first gen tensioner bikes all the way up to the current models. The ZR6 tensioner was known to be a little on the stiffer side; so those need to be pulled out and reset when doing the valves(good idea anyway)...other than that you should be good to go...oh yeah, some have O-rings and some don't so make sure you find one that matches O-ring position...The tensioner body will break before an o-ring compresses so don't make that mistake.

[jwill7]

Awesome, thanks for the info. Have you ever heard of replacing the plastic runner? I was thinking I could counter-sink a hole and bolt on a newer better plastic that would last...or maybe stainless?

[Guest]

I haven't ever had an issue with wearing out the plastic runners; if they are gimped up just replace it while you're in there...I don't know if those fit cross platform or not. I really don't suggest a DIY patch or whatever in this area...if whatever fails, that shit will be flying around inside your engine.

[jwill7]

Yeah, I should just do it right. Guess I'll leave the engineering to the Japs. Thanks for the help.