MZ/MuZ Riders

To all
My speedo ceased to function last week after flickering for a day or two. On examining the rear wheel speed sensor unit I discovered that the tip of the pick-up had been worn away with corresponding marks on the disc mounting bolts. I have tracked down the cause of the problem and isolated it to the disc side wheel bearing showing signs of wear, allowing the wheel to move "out of plane". There are four wheel bearings in the rear wheel (6205.2rs x2 + 6206.2rs x 2) and I am about to replace them all. The point of this missive is to advise any owner with a machine having covered 20,000m or over to inspect the rear wheel bearings as the new sensor alone is going to cost me £109!

One thing I've noticed when changing rear tires is that the 1st outer bearing on the cush side comes out rather easily...I can literally stick my finger in it and pull it out The others seem tight, I'm sure this is not good as the aluminum hub would be the item out of spec in this case...anyone else notice the same? I'll scrutinize them all next tire change as I've got almost 30,000 miles on mine now.

LW
Thanks for the info, I will examine this particular bearing fit whilst replacing said item. Looks like I might need to purchase some Locktite bearing fit in advance.

to all
Bad news I am afraid lads, removed brake disc side wheel hearing only to find that bearing was ok but outer had been rotating in the wheel hub casting. Am now faced with the choice of (1) machining the bearing socket oversize and sleeving back to correct. (2) finding a bearing with o.d to match worn socket.
(3) Welding socket and machining back to size. (4) utilising a metalic epoxy to take up wear tolerance. Wish me luck.

To all
Latest in the speedo drive/wheel bearing saga. Replaced wheel bearing using Devcon Aluminium (sorry Aluminum for our American cousins) epoxy resin to take up clearences and replace worn areas. Also found drive sprocket hub bearings loose. Removal of these double (back to back) bearings proved problematic as the repair manual does not illustrate the construction very well. The outward face of the bearing assemly is covered by a cap that can be prised off to reveal a circlip (or C-ring). The bearings can then be drifted out in the normal manner after some mild heating if the sprocket/cush drive hub. I also bedded these bearings on a Devcon base. One tip, if you do not want the bearing outers to bond wth the resin then a fine smear of silicone grease over the bearing outer will help. I do not usually recommend commercial products but having used both DEVCON and BELZONA for industrial applications i can vouch for the fact that they are serious industrial resins and along with products from the Philidelphia resin co are worthy of consideration for this type of repair.

to all
Final note re the speedo sensor. Have fitted new one (£109 phew!) and added shims to give at least 1mm clearence between sensor face and disc bolt heads. Speedo now works but engine warning light will not go away. I think I will re-boot EMU, if not its a trip up to Grahams for a chat to the diagnostic unit.

well lads
Removed rear wheel today to check for worn bearings, found sprocket side wheel bearing outer had been rotating in wheel casting. Refitted new bearing utilising Devcon Aluminium/Aluminum resin as a bedding compound after roughening bearing race outer/peripheral face and casting recess. Seems to be ok. One day I will have to build up both recesses with weld and machine back to a good interference fit. I would advise fitting a shim between the outer domed bearing cover and the inside face of the disc caliper carrier casting. This will offset the wheel to the right (viewed from behind). You will also need to shim the caliper unit the same amount. This should restore a safe clearence between the staionary and moving components. Having your rear wheel lock up without warning can piss on your day.