MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Mongrel on August 06, 2014, 12:55:54 AM
-
I just want to confirm something. Assuming that you have an '86 or newer bike as I do (i.e. the output drive shaft is 20 splines) how swappable are final drive units (not the drive shaft) between different models of K75s and K100s? For instance, I could get a K100 final drive unit and put it on my K75?
I believe they're fully interchangeable, but couldn't find that for sure and just wanted to confirm that. Or would that not work? Sometimes I see part listings that mention the pinion gear ratio and I'm just wondering if that's being done for completeness' sake or if there are actually variable ratios.
-
There are a few different final drive ratios, usually the FD has it stamped on or near the flange to the arm. Which one you end up with makes a little bit of difference to the acceleration/top speed ratio.
I have a K100 FD on my 75 at the moment... According to the PO, that was a cheaper option than getting the bearings replaced in the original unit.
-
I have a K75C with drum brake. Is there a K100 model out there with a drum-brake FD that will give me a lower gear ratio/higher top speed?
-
Other than the number of splines changing, ALL the K series disc brake Monolever FDs are interchangeable. ONLY differences are gear ratio and finish. I don't remember a K100 with a drum brake in the U.S. So, short of converting to a rear disc system, you may have limited options.
-
One more question. Does anyone know how much a final drive unit weighs (closed, dry) approximately?
I'm guessing maybe 20 lbs? Can't be much more because it clearly weighs less than the transmission and I know that weighs 35 lbs or so.