Cam tensioner blues


Very similar design to what Harley has done in their 96in motors. That plastic guide created a lot of problems. I wonder why a simple sprocket tipped tensioner could not have been employed.? Regardless, it seems like Triumph's design is going to be ok as it is proven in the models you mentioned.

I have a 35 year old Benz diesel and a few years ago I dropped the oil pan to inspect the cam chain and explore. Did not even see a cam chain tensioners. That beast has somewhere around 400,000 miles on it. Just goes to show that if you build it right, it won't break. I think most folks are replacing their chains around 500,000 miles.
 
I suspect mostly chain stretch/wear is most of what takes up the tensioner travel. For example I recently measured mine at 146.xx mm at 20k miles. The service limit is 149.xx over 23 links. Thats .118 thousandths over just a section of chain. The adjustable guide wears a little as @warp mentioned. Heres my adjustable guide after 20k miles. Also of note, according to Bob Carpenter, this is usable as is. Bob more or less said what Warp did. Most of the wear and stretch is initial run in.
 
You guys amaze me. There are not that many rockets rolling around on American shores and yet so many passionate knowledgeable "rocketeers" are out there.