Last summer I drove my '81 R100RT to NY for the MOA rally- was a spirited highway ride from the south coast of MA with the speedo buried much of the day. The bike ran wonderfully- 91,000 miles and I am the 3rd owner. Just before I arrived at Airhead central to camp I felt an unnerving clunk from what felt like under my seat. I dialed back the nature of my riding and carefully arrived and enjoyed the rally. My ride home was without drama except for a few more of these clunks- all at lower speeds and during take-off.
My airhead friends all seemed to think I may need a spline lube. I had the clutch replaced the winter before by a mechanic I trust, but who is more of a Ducati specialist. I'm finally addressing this problem.
When I pulled the trani, using a You Tube video as a guide, I found the splines to be clean, with out rust and no visible damage or wearing. They are pointed and shiny. However the seal at the back of the trani is leaking a bit of blackish oil around the base. There is minimal oil residue in that area and not much on the clutch itself but there is some and some tiny metal fragments. I also found the bolt with the center hole at the back of the trani is missing, so from what I learned on the you tube video I have no way for my trani to breathe.
This is my first time pulling the transmission- all is going well, but slowly. Any thoughts on what might be reason for this "clunk" or will a good cleaning, spline lube, and new seal be a good start?
Thanks in advance.
John
'81 R100RT, '82 R100RS, '01 Ducati ST4
• Look at your rear shocks. If they are OEM they need replacing because the seals "left the building" many years ago.
• Is the battery securely constrained ?
• Are the rubber mounts for the battery box broken ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I would have to say it came from the engine, although my shocks are indeed original- good advice. Battery is well mounted, rubber is as it should be.
THANKS for the response.
• Not only can the shocks themselves make wonderful clunking noises, but the rubber bushings inside the eyelets at both ends of the shock will do the same. Those bushings are there to dampen noise. If they are metal-to-metal, then most any road irregularity (doesn't need to be big) could be translated into a loud noise. To test the shock properly, you need to remove the spring which is difficult on the stock shock. That's why most people simply replace the OEM shocks within 10 years. You might consider a set of $220 basic Hagons which are REALLY good. Call Hagon USA and they'll set them up to your specs (your weight, your luggage, your passenger). http://www.hagonshocksusa.com
• A single missed beat of the engine may sound like a "bump" at low-to-moderate speed, but that is unlikely at higher speeds.
• You might also test your head post bearings. With the bike on the center stand and a jack under the cross-over ex pipe to lift the front wheel clear of the floor, sit on a low seat and grab both fork legs at the axle and push-pull with all your strength to detect any play in the fork bushes or head post bearings. None is acceptable. Small play clearances can often be heard as a clunk-clunk.
• Test your wheel bearings on both wheels. Lift the wheel under test off the ground, and position yourself on a low seat at the end of the axle. Grab the tire top and bottom and do the same push-pull motion. You should not detect any play or looseness. Regular greasing of the wheel bearings is easy to overlook and may indicate that the swing arm also needs lube.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Thank you Wobbly. I've had shock failure on other bikes and know the feel and sounds of failed rubber bushings. Head bearings and wheel bearings both recently done. I'm also certain it wasn't an engine skip.
Many thanks again for all your advice.
John
When we investigate "new" noises and troubles, a very good rule of thumb is to review the most recent changes.
In that vein, your renewed head post and wheel bearings become prime suspects. It will take you all of 5 minutes to shake these 3 items and do a double check. Sure it's a wild guess, but it's really the only solid lead you have.
When doing this work, I find it useful to have the woman in my life put on her bikini and sit on the rear of the seat. This lofts the front wheel simply and easily. Then, even if no trouble with the bike becomes apparent, other ideas will certainly come to mind. In this way the exercise becomes a no-lose proposition.
😛
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Pull back the rubber boat and have a look at your U joint and check the bolts connecting the driveshaft to the transmission. One or more could be loose. Another area ( although unlikely ), could be the swing arm area. Your noise started after you had some work done, so using the KISS principle, check the last thing that was done to the bike.
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