Boxerworks.com

Ken's last paragraph pretty much says it all.
UNLESS when the clutch was replaced, the replacement only included the disk and the pressure plate was machined, and too much got taken off.
Oh, not good.
I've gotten some comments about replacing the whole wad...but have read too many posts from people who did NOT replace the whole wad after many miles...and for the cost and time/work involved, I feel I made the right choice.
A facing-job that needs a significantly thicker disk will perform poorly.

I just put a brace on my instrument cluster (hidden by the little dashboard thing) that stabilizes the cluster. No more shaking. The speedo no longer fluctuates, but the tach still does. So, I guess it is either an electrical issue with the cluster or the clutch is slipping. Eventhough the miles on the clutch are not especially high, I'm leaning towards the clutch since I would imagine that if it were an electrical problem with the tach, the tach would either work, or not work. As ken said, I'm probably not that far away from a clutch job anyhow.

If you have an electronic tach, and ignition issues, you'll see fluctuation in the tach reading.

I had a Dyna ignition (came with the bike) and the tach would dance at more than 5,000 RPM, but the bike seemed to run fine. Then the ignition eventually died. Replaced it with a Boyer, and the tach was rock steady. The bike ran better, too. Sometimes slow degradation is not perceived until one has a complete failure.

If you have ignition issues, you might have tach issues. OR, your tach might be indicative of ignition problems.

If you wanna' test the clutch, put the bike in gear, put the front wheel against something which is not gonna' move (car bumper, while car is in park), add some throttle, and release the clutch lever. If you have a bad clutch, you'll know it with that test.

If the clutch is good, you'll stall the engine or smoke the back tire. If the clutch is shot, it will slip.

The tach may be completely unrelated to the clutch. That's my guess.

If you suspect the clutch, test the clutch. It's easy, and it eliminates speculation.

George, blitz' test is a good one and won't hurt anything. (Unless you have so much fun doing it, you do it over and over!)
Try it and report in.
I think 45K miles is too early for a worn-out clutch unless it wasn't replaced properly...maybe they used an old, weak spring or something else I mentioned earlier.

I am biting my tongue over this one. Had I found an employee doing that burn out test on a bike, I would have fired them instantly. No discussion.

I don't know of any shop that did this test. I don't even know where to start on commenting on this. How about safety? Do you really want to unleash this much hp?

Do you want to count up the parts that can shear/break under this kind of stress that just isn't needed?

I will take my meds no and settle down.

Duane Ausherman wrote:I am biting my tongue over this one. Had I found an employee doing that burn out test on a bike, I would have fired them instantly. No discussion.

I don't know of any shop that did this test. I don't even know where to start on commenting on this. How about safety? Do you really want to unleash this much hp?

Do you want to count up the parts that can shear/break under this kind of stress that just isn't needed?

I will take my meds no and settle down.

While I can understand your reaction, from an ownership liability perspective, I do, in fact, know numerous mechanics, motorcycle and car, who consider that the consummate test.

"add some throttle,"
I believe he meant "some" past idle....not WOT.
The comments about smoking tires was, I believe, intended to be funny.
So....none of you EVER stalled an engine with clumsy clutch operation....?

Yes, the smoke the back tire was a weak attempt at humor. I know my two bikes would never come close to smoking a tire. If the tire is smoking, you'll have no reference as to whether the clutch is slipping.

If one were to dump the clutch and smoke the tire, how are you going to know it is slipping?

Some throttle, not WOT. Release the clutch SLOWLY, not dump it. No damage at all will affect the driveline. If it does, you may have found your / another problem. If you're slipping the clutch during normal riding, you're not transferring that much torque through the driveline. Same thing with this test. it isn't run at maximum engine torque.

What is proposed here is not much different than checking the stall speed on an automatic transmission torque converter. (Other wise known as "brake-torque.")

One, of course, should also keep a foot on the rear brake pedal to limit spinning as well.

If the rider can't use his senses (including hearing) to sense clutch slip while riding, if done with some care, this method can also work.

Of course, there is also testing by running in a gear too high, and applying full throttle to induce slippage, but the poster couldn't correlate changes in vehicle speed with changes in engine speed, so this probably won't help him at all.

Thus, the proposed second test.

Sorry for the confusion, and for the presumed use of common sense while executing the test.

George inMinneapolis wrote:I just put a brace on my instrument cluster (hidden by the little dashboard thing) that stabilizes the cluster. No more shaking. The speedo no longer fluctuates, but the tach still does. So, I guess it is either an electrical issue with the cluster or the clutch is slipping. Eventhough the miles on the clutch are not especially high, I'm leaning towards the clutch since I would imagine that if it were an electrical problem with the tach, the tach would either work, or not work. As ken said, I'm probably not that far away from a clutch job anyhow.

Two things...

First, look at the throwout assembly at the back of the gearbox. Under the clutch arm, can you see any of the shiny piston protruding from the throwout bore? If the piston's shiny edge is visible, the clutch is getting thin. If you can't see the shiny part, I'd make real sure that the clutch actually is slipping before tearing anything apart.

Second, in the mid 80s, BMW had problems with instrument vibration on the R100RS model...their fix was to change the composition of the rubber instrument mounts. The revised mounts are the current part number for all mounts. It requires two and they cost less than $2/ea. It might be worth spending the four bucks. The revised mount part number is: 31 42 1 232 245.

$4 for vibration isolation is a LOT more attractive than a clutch replacement!!
Hit send too fast! (dumped the clutch!)
The idea of smoking tires with an R100 from the late 70's -- early 80's is quite a HOOT.
The more I thought about it, the funnnier it got.