While reinstalling the manual tensioner from Kreiger, I checked on something that I had noticed before and had been talking to Mark about. If you look down the bore of the main tensioner hole...not the lower tensioning spring unit...you see that rubbing guide block that the tensioner pushes actually seems to touch or rub the right hand side of the head casting. You have to use a mirror to look straight down the bore, but with a light you can get a good look at the location of the guide block. I had mentioned earlier on another post that the guide block is not right in the middle of the bore but offset to the right. No...there's not a problem with my guide block. You can tell the OEM tensioner has a matching offset to compensate. In fact my rear guide has never even been removed from the engine, even with the installation of a 300 cylinder. And I closely inspected the wear and looked for any abnormalities on the guide blocks while replacing the cam chain. Here's as good a pic as I could take of the bore hole and the guide block. You can see it's right up against the edge of the cylinder head.

 

Now to me this begs the question...is there enough contact or drag there to interfere with an automatic tensioner perhaps? With the engine together and operational it's just about impossible to tell if there's drag on that guide block and the cylinder head casting. You can't really move the guide block. During a valve clearance check with the cams out, I'm pretty sure you could work the guide block back and forth a bit to get a feel for any drag. Now, I don't think there's a bunch of drag here or anything to really stop the guide block, but now I'm wondering if there's just enough possible contact to interfere with the automatic tensioner operation in some cases. It could explain why some bikes experience a tensioner issue and some don't. I don't know. This is just some speculation on my part.

I installed the manual tensioner with the allen head nut on the end of the tensioner plunger. It is an improvement over the acorn nut. While there's still not much room due to the proximity of the header pipe, it's easier to work that allen head nut with a short cut-off allen wrench than the previous acorn nut. There's just not much room for a open or closed end wrench. I did the cold adjustment using the finger tight method, and it seems to be just about right. I pulled out the OEM tensioner and measured 29mm of extension of the plunger to the face of the tensioner body. I pulled out the manual tensioner after the finger tight method, and it was also 29mm, so things seem about right. After replacing the cam chain, my OEM tensioner seems to work fine, but as the chain wears it may end up doing the same thing as before.

Anyway, I'll run the manual tensioner to see if any issues develop. It's pretty simple and straightforward. The plunger end hits the guide block dead center, so it looks like Mark got the dimensions of all components dead-on.

 

Cool,

Thanks for posting this stuff. I haven't looked at my tensioner much at all but I will be ding a clearance check this winter and will learn more about it then.

 

wow, thanks for all the info TNC!! for now i manually adjusted my auto tensioner, but definitely update us on this manual one as time passes! this would be something I'm interested in for sure!