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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Masonjar on June 21, 2013, 10:53:49 PM
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I posted this on the yahoo kbike list a while ago, but have heard similar questions come up from time to time and thought I would post here as well as I frequent this forum quite a bit.
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Hi all,
Wanted to post my findings on my recent output shaft transplant surgery, this list has helped me tremendously in the past and if I can contribute here I'd like to.
I have a 1985 K100RT. Ever since I got it it has been plagued with the awful output shaft vibration noises, all through the mid rpm range and always especially obnoxious during deceleration or any sort of engine braking. The bike ran strong, and I took it on several longish trips like this, who knows it may have ran forever without a problem in this state. But the noise was just too much for me to bear.
It took me a little while to diagnose, last year I replaced all of the timing chain guts up front, which I'm glad I did, but that did nothing for the noise.
So when I finally decided it was for sure the output shaft and got brave enough to dive into the job, I knew for a fact I wanted to upgrade to a newer model shaft with 12 rivets and another decade or so of engineering. I started hunting around on ebay and desperately trying to cross reference part numbers for different models.
First of all, when I removed and inspected my original six rivet output shaft, the rivets were fine. Main issue was the tensioner spring between the absorber gear and idle gear. The holes were worn out of round exactly as noted in Bert Vogel's restoration article, apparently causing the noise and vibration:
http://hrsbstaff.ednet.ns.ca/bvogel/K100/K100.htm (http://hrsbstaff.ednet.ns.ca/bvogel/K100/K100.htm)
Long story short, after some trial and error here is the combination of newer parts that worked for me:
Entire output shaft assembly from a 2000 K1200LT. I found a perfect low mileage assembly for $95.00 shipped. I had to swap the main bearing from my 1985 shaft, otherwise it's a perfect fit. The engine casing has a groove cut into it that the old bearing fits into and the new one does not. See photo album below.
From this same bike (2000 K1200LT) I bought the water/oil pump from after botching my seal replacement/impeller upgrade job and it was a direct bolt on replacement.
The second item I needed for this conversion (discovered upon reassembly) is the clutch housing. The inner diameter of the newer output shaft, the hole that the clutch housing fits into, is smaller.
I found the clutch housing for a 1998 K1200RS in perfect shape for $45.00 on ebay. All my other original clutch parts (which we're in good shape and within spec) fit it perfectly, and the entire bike has gone back together just fine.
The bike is running like it never has before. Idling perfectly, accelerating faster, vibrations are gone, noise is gone, I'm one happy camper. So far I have about 1350 miles on this build and no signs of any problems.
I took my time, tried to clean everything thoroughly, replaced any o ring or screw or nut that the manual said to replace on the way, and upon reassembly I let the sealant (I use hondabond) cure for a full 24 hours before I added any fluids. Back in love with my K.
Here are a few pics of the job to clarify:
https://picasaweb.google.com/110434671847903585854/1985K100OutputShaftTransplant\?authuser=0&authkey=Gv1sRgCJaL2ZSe983r_wE&feat=directlink (https://picasaweb.google.com/110434671847903585854/1985K100OutputShaftTransplant\?authuser=0&authkey=Gv1sRgCJaL2ZSe983r_wE&feat=directlink)
Thanks everybody, hope this helps somebody at some point in the future. You never know.
David-
1985 K100RT (with frankenstein front end)
Nashville, TN
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greetings mason jar...
welcome to the world famous motobrick.com...
thank you for your positive contribution... im sure some of the snow belt tinkerers round here are already thinking winter wrenching... this just might end up on their lists...
j o
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Hi Masonjar,
Can you check the link to the Picasa album, doesn't seem to be working and I really want to see your pics!
Thanks,
Bill
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Just tried it on a strangers computer and it still worked. But try this one as well, it may be something weird with picasa changing to google plus.
https://plus.google.com/photos/110434671847903585854/albums/5769905602611123809?authkey=CJaL2ZSe983r_wE
Let me know!
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That worked. Great pics, interesting project, thanks for sharing.
It's amazing how many parts are interchangeable on bikes made 15 years apart.
I like the color on your bike too.
Cheers,
Bill