Interchangeability of Cam chain Tensioners

[SherpaT]

So I have a 75' XS650B which has the type "C" tensioner. The cast cap that covers the tensioner and seals with an oring is cracked from over tightening. I have tried to repair it to no avail. They seem a bit hard to find and expensive. I have a 78' parts bike on the other side of the country which I think has a type "D" tensioner. Can I just bolt the newer style one on? I think there is a bit of an issue with possibly over tightening with this later tensioner? Thank you in advance.

 

[5twins]

In your case, yes, you can swap the newer type D assembly on. You will need the complete unit including the housing. What won't swap are the earlier units with the little sprockets on them. They are for the earlier cam chain which has a different pitch.

Now, while the type D tensioner will work in a pinch, I do highly recommend updating it to the later type E. The type D has no lock nut for the adjuster screw so it's possible to inadvertently make your adjustment setting tighter as you install the cover nut. Details are here in posts 22 and 23 .....

http://www.xs650.com/threads/cam-chain-tensioners.1056/page-2

Type E tensioner assemblies can usually be found on eBay for around $20 or less.

 

[SherpaT]

Thank you for your response 5twins. I will find out for sure which style the parts bike has soon, hopefully the later version. If it is the "D" version, any tips on getting it adjusted without overtightening? I assume making sure the threads are in good shape and clean. I have learned so much from your posts over the last few years - Thank you very much!

 

[5twins]

If your parts bike is definitely a '78 model then it will have the type D assembly. The type E didn't come along until '79, but not all '79's seem to have gotten it. It might have been a model thing, like Special vs. Standard, or it may have been a production date thing (early vs. late). Unfortunately, I don't have any tips on how to avoid over-tightening the adjuster as you install the cap nut. That's the big issue with this type D assembly, you just can't tell if it's happened or not. Take the cap nut back off to check and it may loosen the adjuster back up as you remove it, so that's not going to tell you anything. If you have one, I think replacing it should be at the top of your "to do" list.