Finally getting round to changing the cam belts on the ST2. It's quite an old bike (Y reg) and I've not done the belts on it before. Problem has been undoing the 6mm Allen bolts on the tensioners - they are all f*** tight!. The horizontal cylinder is done and the belt off. I will replace all of the allen screws before rebuilding. The problem is that I have managed to round off the fixed 6mm allen bolt on the vertical cylinder. The adjusting bolt is loose. So now I am stuck. I am thinking of trying a 6.5 or 7mm allen key (bashing it in and then trying to undo). it is recessed in a difficult position and so not easy to grind off. Anyone got any good ideas?
Yeah, I have a recollection of doing that somewhere else before - may of been when I had to replace a brake disc or something. Using torx does seem to be the advice on the internet that I've just searched through. Not sure of the size to use but I have some in stock and I'll go by playing around.
If the Torx doesn’t work but hopefully does then try using a dremel fitted with a disc and machine a slot into bolt head and then use an impact driver to remove. Works a treat for me every time.
You may have tried this already but the first thing I always do (If you only slipped the once with the standard key) is to hammer with a flat punch on to the head of the allen screw as this serves the purpose for two things, it can help to free the screw just from the hammer blows alone and it also closes up the internal hex enough to hopefully have a second go with the standard Allen key.
I have tried using an impact driver with a socket type allen head. I think that it is to far gone for this to work.
ok, if you have slipped many times then I understand but still worth trying as it is not the same as using an impact driver, you need to try and close up the internal hex - if you manage to close it up enough that makes inserting std hex difficult then this is the best attempt you will have without going to oversize star/hex etc. It might seem a bit extreme to hit hex head this hard but similar approach has worked many times for me. As long as the thread isn't corroded it's a perfect candidate for above method provided you haven't slipped with std hex several times.
I don't know if you would have sufficient access but these tools for removing rounded nuts have worked for me in similar situations.
Removed the f***er!!!! A T45 Torx socket hammered on to the bolt worked first time! Both belts are now off. I reckon that the 6mm hex socket that I was using is slightly rounded. Gonna bin it and although I have others, I may invest in something high quality - Snap-On, Facom, etc I feel very lucky. This could of gone very badly. This bolt it by far the most difficult to get at with frame, wiring and all sorts in the way....
Take the bolt right out that you’ve managed to slacken and try gently tapping the whole tensioner anti clockwise, you may not be able to move it much but it may move the bolt just enough to slacken it, it’s worked for me on these and various other things. Worth a try.
I put on the new belts this afternoon, Very careful with markings to get alignment correct. Turned over the engine by hand multiple times and all seems good. Not going to throw the old belts out just yet. I'll wait till the whole job is finished. Went to put them to one side and one has red lettering on and says 'Exact Fit'! Sh*t, sh*t, sh*t!!! This muppet has replaced the old belt with the old belt whilst the new belt is in the junk pile! Good job the Exact Fit belts are so distinctive!
