The plan was to replace the belts yesterday and get my ST3 back together to enjoy a ride in the sunny weather today. The old belt on the horizontal cylinder had a shiny and notched back and felt rather brittle, then found both the bearings on the tensioner were seized - bugger! The bike is still in bits while a wait for new bearings to arrive, at least they aren't expensive. It's perfect biking weather but I'm going nowhere :-( My guess is the belts were set too tight last time they were changed, is this common failure on the ST3? The bike has done 24K, so not sure whether to change all the cam belt bearings (fixed and tensioners) or just the ones that seized. Cheers Mike
Are you saying the engine was running normally with the belt tensioner seized? So the belt was going round, turning the camshafts, sliding over the fixed tensioner all the while, and the belt didn't snap? And you only discovered this at routine service? If that is so, you owe a big thanks to that belt which has given you service far beyond the call of duty. If a belt is set far too tight, you would expect the belt to snap before the tensioner bearings fail, surely.
Yep, the tensioner bearings were seized, the inner one looked more cooked than the outer, there was some movement in the outerr one, but the belt held, lucky for me. New bearings and belts on now, but I'm gonna check them after a few hundred miles.
BTW the aforesaid belt is going in a frame a will hang on the wall, it's saved me a pretty penny or two. The bearings are in the bin
When I had to change buggered inlet closer rockers on my ST4s earlier this year I discovered that several of the belt spulley bearings were buggered too. None wear seized but all were sub standard. Mine had done 43k miles.
