Bike has 141K, 8K by me including 2,500 mile high speed run from Houston to Denver and back.
Previous owner had the rear drive spline rebuilt, new valves, guides, seals, springs, and pushrod tube seals replaced at 130K.
Vibration started as slight and progressed in 200 miles of riding. Worse under acceleration. Goes away on decel, braking, or pulling in the clutch. Slight leak at bevel drive to wheel spline seal. Fluid 100ml low after 6K miles but there was some oil at top of breather cap. Driveshaft oil level was fine. Slight metallic sheen in bevel drive oil. In neutral, rear tire off ground, back wheel spins with one finger with a slight tight spot. Shifting into gear from neutral is still quiet, no banging into gear. Clutch slips on hard accel in fourth gear.
Would hate to put in clutch and miss something and have to pull it apart again. What is my next move? When I was young and bull headed, "Run it till it breaks and then fix it." was what I lived by. I do not want to wait until something breaks.
Appreciate any help.
Thanks Scott. Will get back into it by this weekend. I hadn't even thought about tranny bearing. If that's the case good thing I am not riding it anymore trying to figure it out.
I have no experience with bikes over 100K miles, and would defer to Scot on that.
However, on an R100RS with 85K, I was able to cure a very uncomfortable vibration with basic tuning. This vibration would start about 30 minutes into the ride. It would slowly phase in and then slowly phase back out, as if it was a drive shaft bearing or U-joint going bad. It would also stop as soon as the throttle was rolled off. Very strange stuff.
This vibration completely disappeared by doing the following...
► Set the ignition timing with a strobe lamp at high RPM using the fully advanced timing mark "F". This is achieved at about 4500 RPM.
► Set the carb balance at idle (1000 RPM) and throttle cable balance (~1800 RPM) using a manometer, after checking the carb diaphragms for holes.
These 2 steps completely changed the entire character of this particular bike. I recommend at least a cursory check because it's easy and free.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Thanks Wobbly. Will keep that in mind as it just started running on one cylinder for a few seconds after start up. I sure want to eliminate the rear end and tranny possibilities first.
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