Apologies in advance if this part has been covered before, I've looked around on here to try and make sure I'm not covering old ground.
My 64 plate 650GT has always had a concerning rattle from the right side of the engine, sure enough, took it apart yesterday and I'm 100% sure the tensioner is the issue. So, in a fit of enthusiasm I took it to pieces to see what's happened. Here's where I should have taken pictures, sorry, I totally forgot in my excitement. The tensioner works by a little shaft (course, acme thread, almost a helix, very stretched out) being expelled should there be any clearance. The expelling is done by a fine, wound spring. It's a little difficult to describe but..the tension on the spring is added via the hole in the top, I used a small screwdriver to preload mine but, the amount of turns you introduce at the other end as you put it together determines the final throw of the tensioner and how many turns the spring can deliver. It took me a while to figure this out but I'm convinced, in my case definitely, the only reason it "failed" was it literally hadn't been wound up enough for the little jack screw inside to be expelled to take up the required clearance. And, although I wish I could afford to do the hydraulic conversion (BMW dealership I went to said no chance as a recall) here's a thing, after a bit of nosing around I found a Hyosung GT650 tensioner, brand new, delivered from Malaysia for around £23. It looks identical although I've not double checked yet. They put this part on YouTube with a bloke measuring for the camera.
So, I'll report back, I'm going to pop mine back in pending a new gasket and go for a ride. Apologies for being too long. 👍
My 64 plate 650GT has always had a concerning rattle from the right side of the engine, sure enough, took it apart yesterday and I'm 100% sure the tensioner is the issue. So, in a fit of enthusiasm I took it to pieces to see what's happened. Here's where I should have taken pictures, sorry, I totally forgot in my excitement. The tensioner works by a little shaft (course, acme thread, almost a helix, very stretched out) being expelled should there be any clearance. The expelling is done by a fine, wound spring. It's a little difficult to describe but..the tension on the spring is added via the hole in the top, I used a small screwdriver to preload mine but, the amount of turns you introduce at the other end as you put it together determines the final throw of the tensioner and how many turns the spring can deliver. It took me a while to figure this out but I'm convinced, in my case definitely, the only reason it "failed" was it literally hadn't been wound up enough for the little jack screw inside to be expelled to take up the required clearance. And, although I wish I could afford to do the hydraulic conversion (BMW dealership I went to said no chance as a recall) here's a thing, after a bit of nosing around I found a Hyosung GT650 tensioner, brand new, delivered from Malaysia for around £23. It looks identical although I've not double checked yet. They put this part on YouTube with a bloke measuring for the camera.
So, I'll report back, I'm going to pop mine back in pending a new gasket and go for a ride. Apologies for being too long. 👍