Hi Fellow Ducatisti,
I have a 75 Sport and have owned it since 1979. I raced it in the 80s (mostly at Laconia, NH) and have lived in Connecticut, Los Angeles and now in CT again. I have had a chronic problem with my rear wheel alignment / adjustment for years. Just put on a new rear sprocket and would like to solve the problem once and for all:
When I ride the left side adjuster goes slack and backs off about a couple of millimeters. This essentially cocks the axle slightly and misaligns the wheels. It happens no matter how tight the axle is. Any ideas on how to keep this from happening?
Cheers,
George
Rear Wheel Alignment
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75Sport George
- Cucciolo - the Lil Pup
- Posts: 2
- Joined: Mon Jun 14, 2010 5:05 pm
- Location: Connecticut
Hi George,
Welcome to the site. See if you can get Steve to copy this thread down to the wheel, brake and tyre shop for more views.
What comes to mind is the threaded adjuster on that left side. Have you pulled it all out to check the threads on the adjuster sleeve?
If those threads are striped it may allow you to adjust it but moves under the pressure of on/off throttle. Check the threads on the adjuster rod that goes into the sleeve that slides into the swingarm and that the axle slids through. The previous owner may have tried to adjust the chain without loosening the axle and buggered the threads
At the risk of saying something you already know since you raced the bike, how tight are you running the chain? You should have about an inch to and inch and a quarter of slack on the lower run with the bike on it's wheels and you on it. It will feel sloppy on the center stand this way but you don't ride it the center stand. If you adjust it for chain play while on the center stand it will go tight on you once you put weight on it. If it runs tight it will put a lot of pressure on your adjusters not to mention the countershaft bearings.
Let us know how it's going.
Dean
Welcome to the site. See if you can get Steve to copy this thread down to the wheel, brake and tyre shop for more views.
What comes to mind is the threaded adjuster on that left side. Have you pulled it all out to check the threads on the adjuster sleeve?
If those threads are striped it may allow you to adjust it but moves under the pressure of on/off throttle. Check the threads on the adjuster rod that goes into the sleeve that slides into the swingarm and that the axle slids through. The previous owner may have tried to adjust the chain without loosening the axle and buggered the threads
At the risk of saying something you already know since you raced the bike, how tight are you running the chain? You should have about an inch to and inch and a quarter of slack on the lower run with the bike on it's wheels and you on it. It will feel sloppy on the center stand this way but you don't ride it the center stand. If you adjust it for chain play while on the center stand it will go tight on you once you put weight on it. If it runs tight it will put a lot of pressure on your adjusters not to mention the countershaft bearings.
Let us know how it's going.
Dean
Faster, faster until the thrill of speed overcomes the fear of death.
Hunter S Thompson RIP
Hunter S Thompson RIP
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75Sport George
- Cucciolo - the Lil Pup
- Posts: 2
- Joined: Mon Jun 14, 2010 5:05 pm
- Location: Connecticut
Dean,
Thanks for the response.
I looked at the adjuster and don't see anything funny. The axle is surrounded by the adjuster with just a little clearance and threads look good. (When the axle shifts, it moves including the adjuster.) I think that somehow the whole axle is shifting, but that doesn't make sense. My mechanic friend though that I might be missing a bush/spacer on one of the bearings (as many bikes have). The bearing on the sprocket assembly may be bushed but if so, it is in place. I think all the bearing surfaces are lining up and all the ID's are 17MM thus making a solid, continuous assembly.
Not sure how to move this question to wheel and brake (or is it already there?).
George
Thanks for the response.
I looked at the adjuster and don't see anything funny. The axle is surrounded by the adjuster with just a little clearance and threads look good. (When the axle shifts, it moves including the adjuster.) I think that somehow the whole axle is shifting, but that doesn't make sense. My mechanic friend though that I might be missing a bush/spacer on one of the bearings (as many bikes have). The bearing on the sprocket assembly may be bushed but if so, it is in place. I think all the bearing surfaces are lining up and all the ID's are 17MM thus making a solid, continuous assembly.
Not sure how to move this question to wheel and brake (or is it already there?).
George