| Author | Message | ||
     Evomx |
I have a 98 M2 with 28000+ miles on it. I was on a trip last week and noticed a bit of play in the right rear wheel bearing. I already had an appointment to get new tires put on so asked them to replace all the rear wheel bearings. I got a call today and apparently the rear wheel is trashed from the race spinning in the hub. Drat. I've always had the local dealer do tire changes and they've done a full service at each 5000 mile interval. I've never personally adjusted the drive belt, but I've double checked it occasionally against the service manual I have. It specifies 7/8 to 1 inch of upward deflection with the bike upright in neutral and no rider. My owners manual has the same measurements. It's always been at 1 inch or a bit more so I've always thought that everything was cool. When I noticed the play in the wheel bearings, I thought I'd see how tight the belt was with me sitting on it since I'd never checked it that way. Tight as hell. Hmm, I'm guessing that's the culprit for my bad bearings and wheel. Probably hurting ride quality and causing unnecessary drag too. I'm a little frustrated by the situation. From reading BWB it looks like it needs considerably more deflection than 1 inch. I'm sure my dealer, which I've had a good relationship with, has been dutifully adjusting to the same spec that's in my service manual. I've already discussed with them and when they put it back together they're going to make sure it gets adjusted correctly regardless of the shop spec and I'll check it good when I pick it up. I have one theory that the recall shock is a bit shorter than the original, which causes the bike to ride higher and because of the suspension geometry, the deflection spec needs adjusted and never was. Mostly just venting, but I'd be interested if anyone has had this same thing happen and tried to get any retribution. Also, interested how much deflection a person should expect with the rider on? I assume there should be a little since the swingarm is still a ways from being inline with the swingarm pivot and pulley centerline. Thanks! K Wagner | ||
| Reepicheep |
Evomx... not only will it trash the stuff you mentioned, but it will lunch the bearings inside the 5th gear drive assembly as well. Pull your belt off, put the bike in neutral, and turn the front belt sprocket by hand. If it is crunchy or notchy at all, you have a problem, probably with the bearings in the 5th gear drive assembly. It is a PITA to fix, but ignoring it will make it even MORE of an expensive PITA, as the now broken bearings will chew up the transmission shaft that sits in there, meaning that much more has to be pulled and replaced. If those bearings are trashed, and you are doing the work yourself, email me offline. In hindsight after doing the job "by the book", I think I might have figured out an easier and cheaper way. It might not work, but it would be cheap and easy to try. I don't understand the factory specification. It cost me a lot of time and money, and is obviously wrong. Either adjust the belt "scary loose" (I adjust it so I can just get it to touch the top and bottome swingarm under light pressure while I sit on the bike), or pull the shock connection and excercise the swingarm through the entire range of motion and make sure it is not binding. | ||
| Evomx |
Thanks for the tip Reepicheep. I'll call the shop today and ask that they check it since the belt would be off now. When you have the belt adjusted so it will touch the top and bottom of the swingarm with you on the bike... is that the top and the bottom touching at the same time or the top will touch and the bottom will touch if deflected one at a time? I doubt I can use this method anyway since your M2 would have the new wide alum swingarm and I've still got the skinny steel piece. Thanks! | ||
| Reepicheep |
No, I do the top and bottom independently, and you are right, I have the wider swingarm. In general, between two and three inches of free play is probably fine, but the really right way to do it is disconnect the shock. | ||
| Evomx |
If I disconnect the shock and move the swingarm through it's arc, how tight should the belt be at it's tightest? I thought it was interesting that when I dropped the bike off, I walked past some 2004 Sportsters in the showroom and out of curiosity checked their belt tension. It looked like the swingarms on the Sporty's are pretty much in line with pivot and pulley just sitting on the sidestand. The belt was tight, basically no freeplay that I could feel. | ||
| Reepicheep |
If you disconnect the shock and move the swingarm, then so long as you don't feel the motion of the swingarm binding as a result of belt tension, you should be good. Maybe give it just a hair extra slack to compensate for possible belt swelling (which makes it effectively shorter) and isolator loading (which would do God knows what). If you have the full range of motion, adjusting for an inch of slack at the tightest point should make it darn near bulletproof, I would think. Let us know what that ends up looking like with everything hooked back up and the bike back together. | ||
| Sportyeric |
I've had to figure out belt tension on my own with a change to longer shocks on the Sporty. After the intial install and adjustment, I was amazed at how much it tightens up when hot. I couldn't believe that the rear pulley could expand that much! Reepicheep's suggestion of belt swell makes a lot of sense. My recommendation would be to do a final check with everything hot and load the bike enough to put the three points in alignment. (Pulley centres and swingarm pivot.) |
