Cam-chain tensioner second thoughts 🤔

Shaun2007

New member
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. 👍
 

Ceesie76

Active member
I can't really comment too much, but a new mechanical tensioner from BMW is about $75 in the US so I would recommend sticking with the BMW part rather than trying something else - too important to fail. As for instructions on replacing the thing, there's a good write-up in the shop manual (of course) which I recommend you get on DVD since you are attacking this yourself. I found mine on Ebay. Had toget a cheap external dvd reader since my laptop doesn't have one.
I have the new BMW mechanical tensioner sitting on my workbench, along with the special cam fixing tool, but am waiting on new idle air hoses so I can replace the old ones at the same time as replacing the tensioner.
 
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock
No Thanks