crashed my rt on May 15th - had to be airlifted to hospital. broken ankle- rib- 3 broken vertebrae - separated shoulder. Going about 30 to 35 MPH on a very slight curve. Herd a loud grinding noise from underneath bike. bike would not turn and went straight off right side of road into a nearby utlity pole which was only 2 feet or so from pavement. Don't remember impact. bike struck pole at slight angle since from fender and front wheel undamaged. I was thrown about 10 feet from pole and bike which remained near the pole. I have been physically unable to review the scene but was told there were some scratch marks on the road leading off the road starting about a foot or so from the edge of the pavement.
Cant start bike but tires are up and it will role. while in gear (seems to be 3rd) rear tire will rotate making poping noises. Any one with any ideas what might have happend - anyone heard of the rear wheel suddenly locking up?
Mike -

What an absolute bugger so sorry to hear that. Don't forget to take a 1000mg tablet of vitamin C plus a good multivitamin everyday to help your body fight the repair work. Now to your bike any chance the centrestand spring failed and that came down although I would expect it to bang up and down not dig in. How about the under the engine fairing (if you have one) could the screws have come out so it dropped down?
Regards,
K-BIKE

hi,

Real scary story, I think we can all benefit from understanding what happened.

Again, ATB and let us know how u r doing.

Roy

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Hi Roy,
Without doubt it is possible for the gearbox to lock and the final drive as an alternative. Neither of these possibilities will be able to be helped if you pull the clutch in, which would be really frightening.
Regards,
K-BIKE

Holey Crap! Hope you get back on your feet soon! I was wondering if there was any loss of speed or power, could it have been the rear suspension failing? or the transmission spline failing and taking out some of the drive? I'm gonna have to take a long look at mine for sure. If you lose the final drive fluid would that result in it failing horribly like this or would it just grind itself to bits and slowly lose power. Hope we can shed some light on this, keep your chin up!! Cheers B

Mike,

Sorry to hear about your crash. from the description of your injuries, I believe that your riding season is over for this year.

Even if the springs of your center stand broke, the stand would have bounced over the pavement.
It could be the possibility that the stand broke and a hanging piece grabbed on the asphalt. The original stands of the 1985 were known to collapse and the bike crashing when parked. The stand were braking on the left side and BMW replaced them with the new models having a gusset.

Can you locate if the popping comes from the back of the bike or near the gear box?
While in gear, it should be impossible to turn the wheel unless something broke between the wheel and the engine output shaft.
I never heard about the crown gear teeth braking but what I heard (more than once) is the splines on the drive shaft breaking. The noise is comparable to a fast ratchet. Could it be compared to a loud griding under the bike? I would believe so. Would losing driving power in a curve could lead to a crash? Well it certainly could be a factor. The splines may have been slipping then grabbed again having for result to have the tire jumping on the road.
When the splines break, it is usually when you accelerate or decelerate but not at a constant speed. If it had been a mechanical problem with the gear box (locking up), a set of badly worn splines would not withstand the sudden change in torque and would break. This scenario implies 2 separates problems but in fact they are related to each others.


When the splines are worn, if you manually turn the wheel the teeth are jumping in the spline and make a type of popping sound.
Here is a picture of the drive shaft from my K75 (lots of miles on it). It was at the limit of breaking. You can easily imagine the noise that it would make when the drive shaft is turning at engine speed and the wheel is turning at a different speed.

Mike, get well, and when you will feel better let us know your finding.

Bert

Thanks for your replies -- what I know so far is that the centerstand is Ok and the side stand seems ok. My first thoughts was that the front or rear tire had gone flat and the grinding was the rim against the pavement, but both tires are fine. Something is definitly amiss in eihter the trans or final drive. When I am physically able I will investigate further an let you know what I find. My gut tells me the rear wheel completley locked up which cause me to continue in a straight line and also cause the bike to yaw as I left the pavement striking the pole at a slight angle.
Mike

What about the link in the drive shaft? Wouldn't be the first time that one of those fail and that would be pretty drastic!
All the best for your recovery!!
Cheers, Rene.

PS Bert, I hate seeing that picture. NEED TO DO A SPINE LUBE SOOOON!!

ReneZ wrote: PS Bert, I hate seeing that picture. NEED TO DO A SPINE LUBE SOOOON!!

This would be a good test part for the aluminum welding rods that K-Bike found.

Hells Teeth mate. I send my best wishes and do try to keep your spirits up. Final drive problem? Who knows, but I have just re-assembled mine after renewing the clutch and it has made me think, did I get everything back in place with care!!
I found a big problem during the job, and it might (only might) be a worth a look. The spring clip that holds the rubber gaiter on to the end of the shaft drive had come off its seat and had travelled and wound it way ALL the way down the shaft. When it stopped at the end of the shaft, it has proceeded to cut a deep (I mean deep) groove in the shaft. Almost right though it I would say. I replaced it with a brand new shaft as it was clear it was very damaged and weakened. My mechanic buddy and I were a little shocked at the implications of the shaft drive failing when riding, after the spring clip had finally managed to saw right through unseen by human eye as the bike was moving. Might cause the rear wheel to lock up?
All the best,
Boris the Bike.
PS A good malt whiskey and time to catch up on those good books.

Wow. So sorry to hear about that scary event. Best wishes for your recovery!

When you feel up to it, please let us know what you find caused the failure.