Change my snowflake rear end for an LS...

[Semper Gumby]

Hi Guys,

I know its been a while...

BUT I just did something that somebody else might want to do.

The splines were worn out on my snowflake rear end both the wheel and the final drive so I bit the bullet and and went looking for LS parts to sort of match my K100RS front end I have on the bike.

So I found a post 9/80 square rear end 32/9 off of fleabay that looked like it had pretty good splines.  I found a LS rear wheel with good splines over at Nathans (Boxerworks).  

The wheel went to Metro wheel Marietta GA for straightening and powder-coat (White).  Then to BMW of Atlanta to clean the bearings and to get properly shimmed for the preload plus transferring my Michelin Pilot Activ 4.00.  I scored some Ferodo brake pads off fleabay again and the tension springs from BMW of Atlanta.  And I found a machine shop to turn the rear axle shoulder back about 22mm to allow for the wider LS wheel. (In truth it only needed about 18mm).

Today its all done and first test ride all is smooth as glass with no vibrations or noises.  I spent a bunch of money on it but it all works...and no more tubes.  

Picture:

[montmil]

Sweet!  [smiley=beer.gif]

[Tony Smith]

How easy (or difficult) was the K100 front end swap?

Reason I ask is that my R65's forks are bent and "upgrading" is as good as simply replacing.
 
Two questions - Firstly did you swap the entire front end, triple clamps, axle and wheel? If not, what did you reuse and what needed to be machined?


Ok, three questions, counting was never my strong suit

[montmil]

How easy (or difficult) was the K100 front end swap?

Reason I ask is that my R65's forks are bent and "upgrading" is as good as simply replacing.
 
Two questions - Firstly did you swap the entire front end, triple clamps, axle and wheel? If not, what did you reuse and what needed to be machined?


Ok, three questions, counting was never my strong suit

I've also heard of and seen photos of Airheads running late model Jap front forks. Wondering about this myownself.

[Semper Gumby]

Tony.  It was easy.  The part numbers for the steering head bearings were the same number for the 1980 R65 and the 1988 K100RS front end I scored off ebay at 2 in the morning.  Plus I had previously checked with Nathan at Boxerworks and he said that he had done one or two previously.  When I got the parts I took both the bike and the complete front end to Nathan and he did the install.  There is a LONG story behind my decision to procure this front end.  I tried everything: Font end braces, larger tires.  I considered bracing the rear swing arm with the San Jose BMW mod and bracing the frame (all in search of better handling) until I talked with a gent, no longer with us, who said that the R65 swing arm, due to its shorter length, was already the stiffest airhead swing arm out there.

Why I did what I did: the stock R65 front end is too flimsy for a bike with a Side panniers, a top case, and a large front Luftmeister front fairing.  No matter what I did, had unstable steering above 60-65 mph.  The stiffer 38mm front forks of the K100RS front end and the wider 2.5" width of the K100RS 18 front rim gave me steady handling all the way to 90 mph.  Best money I have ever spent on the R65.

The K100RS 38mm forks and front wheel solved All my handling issues.

Now if you do not have a large front fairing to hide the Farkel that is my instrument console then you may want to reconsider this set up.  The stock frame that holds my instrument is is attached on top clamp but is zip tied to the bottom clamp.  I am OK with this but you may not be. No machining was necessary.

regards,

SG

PS Tony - I scored an entire front end: Handle bars, Master cylinder, triple trees, forks, 2.50 X 18 inch rim and tire, with brake rotors, calipers, front fender and axle off ebay at 2am.  I was shaking when I saw it.  I figure I got about $2500 of parts for $400.

Every now and then a squirrel finds a nut!  



PSS - The K100RS front end had the same configuration as the R65 forks.  Both had 18" rims - the K100RS was wider which I wanted for the modern front tires.  Also the axle was mounted on the same place - the bottom of the forks - not out in front as in some of the GS and RT forks.  The fork tubes went from 32mm to 38 mm is the real difference and they are taller.  That does not seem to be a problem with my bike.  Also there is a "S" stamped on the top of the forks so these are "Sport" forks.  Because the forks are taller I changed to center stand to the R100 center stand.

[Tony Smith]

Thanks for that Bill.

I suspected it would be an easy swap.

I've been looking at a Yamaha R1 front end (complete with rim tyre brakes and master cylinder) which is mine for $600. The only engineering required to fit it at a basic level is to drive out the axle from the R65 triple clamps and fit it to the R1 triple clamps.

I am leaning towards the K100 solution though because it is a bolt on and I think I can sufficiently engineer the things to mount the original instrument/headlight bracket which would leave it looking very stock, I might even reduce the length a bit to only 1" or so longer than stock R65.

I intend that the R65 stays a "naked" bike, I have a R100RS and the KLE for hiding behind a fairing.

[nhmaf]

The place to get early K-bike (flying brick) parts cheap is through the beemer boneyard - they have several used fork assemblies available now-
http://www.beemerboneyard.com/completeforks.html

[montmil]

The place to get early K-bike (flying brick) parts cheap is through the beemer boneyard - they have several used fork assemblies available now-
http://www.beemerboneyard.com/completeforks.html

They also offer great deals on Airhead oil filters, crush washers and many other bits that we utilize. Check their site. Well worth the trip.