k75 clutch splines rounded

[MUSICMAN]

93 K75, 67,000 or so miles.
Last year my K bike had no drive power getting onto a highway.
Finally pulled it apart last week and my clutch splines were practically non existent and dry as a bone. The splines seem to have been almost sheared off.

The Input shaft on the tranny has a deep groove about 3/4 of the way back and the splines almost seem slightly bent.

I did a spline lube about 6years ago and only put about 3,000 miles on it. MY GS gets most of the riding. I had also installed a new clutch assembly about 25,000 miles ago.

So what do you think happened? I'm guessing the splines dried out and reaked havoc. I'll try and post some pictures soon.

Fortunately I have a used transmission with a great input shaft. Debating if I should change the seals on it.

Any chance the rest of my clutch parts are still good other than the disc? I'm guessing I should measure them, check for straightness etc...

Thank you,
Andy

 

[dbrick]

If the gearbox splines on the bike are badly worn, then the clutch splines will be worn as well. If you mate worn clutch splines with good splines on a replacement gearbox, the gearbox splines will quickly wear to match the worn clutch splines. Same thing happens with sprockets and chains.

I'd replace the clutch.

 

[mneblett]

A not uncommon wear pattern where there is misalignment between the clutch hub and the tranny input shaft.

In last month's Owners News Paul Glaves discusses a *very* similar situation with Voni's >350,000 mi R11RS, and his detecting a substantial amount of run-out, causing the clutch hub and the tranny input shaft to be not-precisely-coaxially aligned. Paul noted that this had not been a problem with the 2-3 previous clutch replacements he had done on this bike, but that he suspected that he might have inadvertantly tweaked the assembly the last time he was in there. I suspect that may be the case with you bike. New flywheel/clutch carrier assembly and a new tranny input shaft were the ($$) fixes.

 

[MUSICMAN]

the clutch plate is complete toast, will get replaced. I'm hoping to be able to reuse the spring, plates and spring

 

[MUSICMAN]

I wonder what the reason would be to replace the flywheel and clutch carrier?

 

[98lee]

Musicman,

It sounds like your bike is one of the few/several that have the classic transmission/intermediate housing misalignment. You will continue to have the same problem (worn out clutch and tranny input splines until the misalignment is solved.

There has been much discussion over the years as to possible causes and remedies but to my knowledge, no one has actually been able to produce the smoking gun, just plausible theories.

Being an ex-maintenance machinist and millwright at Alameda Naval Air Station, I've had lots of experience diagnosing and solving complex misalignments on machine tools. After the Loma Prieta Eathquake in the late '80s, I was busy for months realigning our huge CNC machines (they're not SUPPOSED to ALL go out of alignment at the same time!).

I've recently worked on a buddy's K75S who had the same symptoms (clutch replaced at the dealer at 30,000 miles and splines were toast at 60,000).. I've developed some methods to measure for any misalignment. After many days of not finding anything showing the source of the misalignment, I finally came across the problem (for his bike. Could be different for others).

I'm leaving for a ride with my wife this morning and the procedure is WAY too involved to write up inside an hour. This is something that I have been meaning to do. I guess your situation warrants that I do it for this forum ASAP.

to be continued.....

 

[ted]

Agreed - i hve seen classic K bikes with no trans spline lube in 40k+, mostly they are a bit rusty but in decent shape. Final drive are a different story, they need the frequent maintenance.

Do you remember what lube you used? Things have come a long way since back in 1995 when I destroyed my K75S final drive splines and driveshaft within 10k miles using BMW's then recommended red cr@p. My new to me K75RT gets Guard Dog GD-525 moly lube.

EDIT - just saw Lee's post... When he finishes with the big write up, I'd print it out and laminate it

 

[MUSICMAN]

honda

I'm looking forward to the write up too as I bet many others are.

I used the Honda Molly paste and I've always had good luck with it.

Andy

 

[deilenberger]

Lee and I have discussed this - and I suspect he may have found the root cause of the misalignment.. It wasn't something I'd think of, so hurrah for Lee and his skill in finding it..

Lee - now for the "rest of the story" (said in my most booming Paul Harvey voice..)

 

[MUSICMAN]

lets see if this works

Here are the clutch splines (lack of), very rounded (the red is my lift)

On the input shaft upon closer inspection you can see the indent wear is way to the back

 

[deilenberger]

Classic alignment pattern wear..

Wait until Lee gets back to you on how to most likely fix it..

 

[MUSICMAN]

thanks for the clarification. I wonder why it's now showing up. I did replace the entire clutch assembly about 25,000 miles ago for a worn friction disc and very slight warping on the plates but the inside of the clutch splines and input shaft were in great condition.

Is it possible I somehow messed up 25,000 miles ago?

The tranny I have to replace the current one with is an earlier silver one.

What if Lee is riding Alaska and back? Another good reason to have multiple bikes.
Andy

 

[PGlaves]

I want to add a clarification. On the Oilheads which I wrote about, the flywheel components are thin stamped steel. On the K75 the flywheel (clutch housing) is a thick beefy cast aluminum piece. It is unlikely to be bent. But the bolt up of the transmission to the bellhousing/auxiliary case, has long been suspect.

On two bikes we've had that exhibited the problem, I found used auxiliary cases, installed them, and installed the transmissions, and have not had a repeat problem.

 

[98lee]

What if Lee is riding Alaska and back? Another good reason to have multiple bikes.
Andy

Naw, it was just a couple hundred miles up the Sacramento Delta and back for lunch, but when Mama wants to go ridin', everything else can wait.

Tomorrow's Easter and we're having a house full. Finish Taxes Monday, Solar (PV) guys are coming by Tues. to tweak the system, 2hrs of work to be done at the dentist Wed. morning. Maybe Wed. after the dentist I can work on it for awhile. You guys don't care if I'm a little loopy from the anesthetic (It's not like I have to be accurate or make any sense do I?? Why start now?)

I've got some picture too.


I'll get to it as soon as I can.

 

[98lee]

Here are the clutch splines (lack of), very rounded (the red is my lift)

Those aren't rounded.





Those are GONE!!!!!

 

[MUSICMAN]

Gone...Like A Nixon File (John Hiatt)

Thanks for updating us Lee, I'm deep in bookkeeping as well, rounding the corner finally.

Ya, those splines are long gone. I was getting some sound from that area and was going to check it out this past winter, but the K gave up sooner.

I look forward to when you'll be able to write it up.

Thank you,
Andy

 

[MUSICMAN]

waiting is fullness

I know you're busy. I'm really looking forward to the read when you can.

 

[MUSICMAN]

bumpity bump bump

 

[98lee]

Andy,

I sent you a PM yesterday.