Cam tensioner blues

[DodahMan]

The tensioner is different and separate from the chain guides (blades) that are nylon or similar hard plastic (and maybe with alloy inserts) and do wear IF the cam chain is loose or it starts flapping around at very high revs in performance builds.

The stock Tensioner is all metal except for the tip in contact with the chain I believe. The stock one has an oil retaining cylinder and the spring loaded pusher that slides inside it. They are generic to a whole range of early and later Triumph models including Daytonas, Trophies etc.

The aftermarketr ones are mechanical thread and hand adjusted from APE and Neville Lush makes an even better custom one for a great price.

Camshaft & Camshaft Drive - Triumph ROCKET III, CLASSIC & ROADSTER | Triumph ROCKET III, CLASSIC & ROADSTER Camshaft & Camshaft Drive supplied next day (UK only) by Fowlers Parts

8 Kit, Cam Blades T1142049

8 Blade, Rubbing Strip, Camchain T1142055
9 Kit, Cam Blades T1142049
9 Blade, Tensioner, Camchain, Alu T1142048
12 Tensioner Assy, Black T1140183
12 Tensioner Assy, Silver T1140180
13 Gasket, Tensioner T1140187
14 Bolt, HHF, Lghtd, M6 x 20, Slv T3205066
14 Bolt, HHF, Lghtd, M6 x 20, Slv T3205066
Replaces T3203020

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.

 

[Jvheli]

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.

 

[DodahMan]

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.