Chain Adjuster Problems
 

A few months ago I fitted a used aluminium swinging arm from an ST4S to my ST4, complete with its chain adjusters and other bits, I did buy a new spindle and chain adjuster plates. I had probably done a 1000 miles when I changed the front sprocket. I went out for a ride today for the first time and after about 40 miles my mate stopped me to say there was something wrong with the LHS chain adjuster. Basically it had worked loose, and the end plate had rotated and has rubbed on the rear sproket and bent the adjusting M8 bolt. Luckily this occured outside B & Q in Christchurch, Dorset and they had a suitable bolt, we effected a temporary repair.

What I need to know is how the hell it happened, why did it work loose, how can I prevent it occuring again and is there a better alternative to the Ducati chain adjusters.

Cheers

Vibration. In giving us the grunt, drive and noise we all love, big V-twins vibrate quite a bit. The chain adjusters on ST's (and monsters and 888's for that matter) can work loose quite easily, as you've just found out.

I've got into the habit now of taking a 12mm spanner to them everytime I lube the chain and just making sure they're nipped up before the ride.

You can replace the bolt with a length of stud of the same size thread and loctite it into the chain adjuster, then use a locknut arrangement or a nyloc nut, but I don't think that looks very pretty so I prefer to just keep checking

This a very common problem on STs (and presumably Monsters with the same arrangement). After adjusting the chain and torqueing the axle nuts it is essential that you tighten the adjuster bolts. If they are not tightened properly (8Nm) they can come loose and get mangled in the sprocket or on the RH side of ABS models can chew up the ABS sensor rotor. There are quite lot of postings about this on US sites, with many owners lockwiring them, but like Jools I just make sure that mine are tight when I lube the chain.

thanks guys, since torqueing the little blighters to 8Nm no more problems