More bits exploding (Drive train related)

[adrianw]

Hi,

Rough couple of months recently.

In November (~76,000 miles) the rear differential exploded while I was doing about 60mph, locked up the rear wheel etc ground to a halt (~£1000 sterling to repair @ the dealership).

GB response : "Have you got extended warranty?"

At the end of January, (~83,000) leaving a roundabout hard on the gas, big metal noises, engine hits the rev limiter. Guess what ANOTHER set of splines in the clutch/gearbox just got polished flat.

This time (last time at ~26,000miles it was the input shaft splines) its the clutch plate splines that the input shaft slips into into that got polished.

The dealers in the UK are charging £55 sterling an hour for labour, and by the dealers own admission, they have no experience in bikes with this milage.

So I've found a nice old man how loves bikes and owns the local garage, who has it in bits right now while we wait for the parts (~£35 sterling an hour.)

Interestingly, after he had stripped the bike he said, that he found no evidence of copper grease on any bolts apart from the rear caliper bolts (Independant Tyre company, not BMW dealer). Shocking, especially when you consider I've had a stainless steel kit fitted about two years ago, and that the bike was rebuilt (All frames/chasis replaced) a year ago after a Certain Welsh dealership crashed the bugger.

So I'm out of the dealer network now.

Adrian.
R11S March 99

[roger albert]

Sorry to hear about all that. Sounds like you've had more than your share of bad luck.

Were both the clutch and input shaft replaced the first time?

On the bolts, you should be ok where the stainless goes into steel, but Stainless or worse yet, Ti, into Al without anti-sieze or locktite is bad news. Good chance to gall and sieze.

Hope the old guy works out for you. I like folks that like independent shops

roger

[adrianw]

Hi Roger,

Glad to see your still about, I don't get round to the site as much, been too busy.

Yes both the input shaft and the clutch plate were replaced the last time. The clutch plate was 'advisory while we've got it open' type thing. Although now I've seen the mess both parts end up in when one set of splines disintigrates, it probably should have been replaced as damaged not as worn while we're here.

Regards,

Adrian.

[roger albert]

Exactly my concern and the reason for my question. I couldn't really call that advisory, other than in the sense that breathing is advisory to make your day go well. You hit the nail on the head. If one set of splines goes, the other is damaged most everytime. I feared that skipping one replacement might have caused the second.

Guess I'll have to blame you now Seriously, lots of fast or power shifts. Any excess play elsewhere in the driveline (which can increase shock to the splines) ? Two of these seems odd.

One other thing to consider is your rear drive failure. If it locked, that put a pretty good back torque on the rest of the driveline. Might well have set you up for subsequent failure a bit later. Likely a contributing factor, even if not solely causal.

Good luck getting it sorted. Have your guy get as much slop out fo the driveline as possible.

roger

[adrianw]

Ahhhh...

Hadn't thought to relate the two incidents....

Does make sense though.

As to my treatment of the bike, I cut down the clutchless shifts after the first one went (didn't bother much with the clutch up or down the box), but I am prone to the odd stoppy, although since the drive shaft went I've mostly being doing those on the wifes zx636...

Adrian.

[Dave Hopkins]

Adrian
Roger makes a good point on relating the two incidents, please also consider the following. Back in the ‘60’s, before Detriot built “Muscle Cars” for us I had a shop and built them for customers. We would buy an aftermarket bell housing adaptor to connect a Olds V8 to a Ford transmission one day, another it was a Buick V8 to a chev 4 speed, etc. Several of these combo’s broke or trashed transmissions with minimal abuse. Finally we discovered those aftermarket bell housing where crude and the transmission was often off center from the crank. To make them live I had to mount a dial indicator on the back of the crankshaft and check to see if the bell-housing’s centering ring that registers the transmission case was centered with the crank. As I recall about .004” was acceptable tolerance. There was one deal a 401 Buick in a 41 Chev with a late model 4 speed that the guy broke about 6 transmissions before he brought it to me, I centered up the bell housing and re-dowel pinned it in place, never broke again. A few years ago I bought a 1996 BMW and every time I stopped and waited for a stop light with the trans in gear, after abt 10 seconds it pooped out! I am betting that bike had an off center component. With the crash your bike had I would give a very close examination to engine to transmission connection, any dowel pins etc.

[roger albert]

And in continuing our mutual admiration society, I'd say Dave makes very good points. I almost said something semi-similar about looking at runout at the back of the crank or transmission input, either of which would chew splines. I've dealt with that on cars and bikes. (I have an airhead trans right now where the rear/output bearing failed such that the flange moved enough to smash the front Ujoint into the back lip of the transmission's rear door/cover and ripped it out. Will make this one a more costly job - bummer.

Anyway, I hadn't even thought of motor or trans misalignment. Can't say if the alignment issues, if any, existed before, or only after the first accident. A plausible scenario is that abuse or manufacturing defect led to the initial failure, which led to a wreck, which led to mis alignment, and then a subsequent failure. I'd sure want that possibility investigated and ruled out lest I expect a 3rd failure down the road.

Good luck, and keep us posted.

roger

[Eron Flory]

Dave and Roger,

To add to your theory of mis-alignment, I worked on a K75, years ago which had a history of spline and clutch problems. After questioning the owner about his problems it turns out it was a salvage bike. I replaced the clutch twice in about a years time and replace the alignment dowels the second time. I didn't see the bike after that (not sure if that was because it was fixed or because I moved to another state) but I suspect his problems were due to a transmission/engine alignment issue resulting from crash damage.

With enough mis-alignment the trans. input shaft splines and clutch splines would always be preloaded and wearing against each other. I would also expect pilot bearing and transmission input bearing wear.

Eron

[Rapid Dog]

Theoretical quesh...

In the event of a tip over, or let's say, mild 45 mph get-off, where the bike spills sideways and lays there, tire off the ground and in gear and the engine abruptly stops, causing the driveline to also abruptly stop, would that concievably cause any concern for driveline/tranny damage?

When I see a bike fall and see the rear wheel whack back and forth in gear, i get the willys...
This business about locking up the driveline at 60 really scares the baens outta me.
Especially since I like to exceed "the ton" on a regular basis.

[roger albert]

Hi,

in the event of the driveline abruptly starting while the bike is on its side, it's not a big deal, since there's very little momentum to cope with (just rotational in the rear wheel, rather than rotational, plus linear movement of that same wheel, and the rest of the bike and the rider. Much less stressful.

On top of that, the motor stopping in that circumstance is most desireable, since you'd likely be starving the engine of oils. Bearings hate that.

To sum up, the force from an off-the-ground wheel is not a big deal, and you should be glad the motor stops.

roger