I just took delivery of a 1978 R100S with an indicated 46,xxx miles (but likely more, as PO said odometer was inoperative when he purchased it some years ago). Bike has extensive service records and PO was fastidious in maintenance. Only indication of drivetrain work was rebuild of clutch pack by Southland within the last 2,000 miles. Upon delivery, I trickle-charged battery overnignt (bike was delivered cross-country over a week). Next morning, I checked all fluids (OK), tire pressures, etc. and it fired up immediately. Ran great throughout its initial 20 mile shakedown run.Today, (several days later), I fired it up again and, again it ran great and got me to my destination about 8 miles away. Two hours later, I started it to return home, intending to take a bit of a detour to hit the highway and take a longer route back. As soon as I shifted into first gear and let out the clutch, it sounded like someone had emptied a bag of bolts into the transmission. Shifting into second made no difference. Clutch in or out made no difference. It was LOUD. Stopped at a traffic light and left it in first with clutch pulled. No difference. Figured I was in real trouble, ditched the highway home plan, and decided (perhaps stupidly) to run it just a little further in second gear and decide whether to bail out the entire ride and call for help. Then, shortly after this decision, the noise vanished completely. Rode it a little more with no issues. Decided to revert to Plan A and hit the highway. Zero issues. I am unable to find much on the internet on gearbox issues on this bike other than that they are usually due for a rebuild somewhere between 50,000-75,000 miles. I'm planning to drop the trans oil and look for metal but wondered if anyone has had experience with this type of issue. Full disclosure: Although I have been riding for many years, this is the first Airhead I have ridden and I know the gearboxes can be quirky. I'd appreciate any advice.
crazy stuff there, can't think of any rotating part that could make such a noise and fix itself.
let us know what you find when you drain/change the fluids.
If you were stopped at a light in gear with the clutch pulled in then the transmission gears are not moving at all and the noise is coming from the clutch area (not the disc as it is not moving) or something else all together.
I experienced a similar noise situation with my 79 R100T....the rattling bag or bolts noise from trans area. Turns out one of the clutch disc bolts came off, flew around in the housing a while till it got jammed up in the bottom. You mention recent clutch work so I'd check that possibility. Redid all with locktite. No prob since.
These comments make sense. Haven't had time to get the bike on the lift yet, but will check trans drain plug first, then dig deeper into clutch. I'm leaning more in that direction now. Many thanks, Gents. Will let you know what I find. Gonna try to hold off until after this Sunday's Annual Gathering of Nortons, though.
Bought an RT that sat indoors, unused for 15 or so years. That gearbox was hard to shift and noisy (at one time I was actually thinking it was a broken spring due to rust). At about ~2000 miles I loaded the gearbox, drive shaft housing, and final drive with some high-end Valvoline 85-140W non-synthetic oil. Whether it was me getting used to the machine or the effect of the oil, all issues suddenly went away.
But my noises didn't sound nearly as drastic as yours. I agree, recent clutch job and banging noise makes me think loose bolt. You might be able to...
a) slide the gearbox to the rear 1/2 inch and fish around with a magnet through the opening, or
b) use a stick magnet down through the starter opening
...before fully committing resources.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Good suggestion R32 Level. Wasn't looking forward to pulling the trans on a hunch. I will give that a try if trans fluid inspection doesn't turn up anything, which I'm beginning to think it won't, as trans is actually working fine.
You can see the clutch bolts through the timing hole.
11771, would I need a borescope to see them ? Thanks!
No, a flashlight will help but if a bolt came out it should be very noticeable.
Thanks! Will try and get to it this weekend, after I finish carb rebuild/synch on my R90/6. Will let you guys know what I find!
Just to close the loop with thanks to all: transmission is fine. Clutch bolt came loose and settled into recess in bell housing. Thank God it didn't wedge into the flywheel teeth. Somewhat major surgery to retrieve/check/ retorwue clutch bolts but could have been a LOT worse. And while trans is out much easier to replace the $&;"@ leaky neutral switch I just discovered on closer inspection. Thanks again!
You also want to check on the sealing of the oil pump plate, which is behind the flywheel. That plate has an o-ring which needs renewing from time to time.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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