RM250 Crank and Crank Bearings interchangable

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4/22/2018 10:10 PM

I have an 04 that I just split the case on and need to swap crank and crank bearings. I try to understand what the differences are on OEM and how I can swap K3-K6 parts.

I got the hold on an almost brand new 12200-37F40 (that is labeled K5-K6 and sold as to fit 03-08) that I'll receive within a few days. I figure that one should fit because when I'm looking at aftermarket cranks same crank fits 03-08.

If I put that one in my 04 case, what bearings should I use? 09262-28027 or 09262-28044 both are listed to fit 04(K3-K6)

This K marking really confuses me.

Any help appreciated



4/24/2018 11:33 AM

"K" refers to the "0" in '01" when describing model years. Thus, a K1 is a 2001 model, K4 is a 2004, K9 a 2009, etc.

K3-K6 means it will fit '03 to '06 models.


Braaapin' aint easy.

4/24/2018 11:41 AM

By the way, your 2004 should accept a 12200-37F30 crankshaft assembly. The newer one has a different part number because of some change to it; I don't know what changed or whether the newer one will fit. I did see that the crankshaft bearings are also labeled as K3, K4 and K5-K6, (three different bearings for the four model years,) so I bet there's enough difference that you may want to really inspect before putting that newer assembly together in your engine.


Braaapin' aint easy.

4/24/2018 12:16 PM

Thanks for your reply @Falcon
I did a lot of google digging yesterday evening and I think I got some of the stuff figured out.

The crank from 05 is slightly heavier according to https://motocross.transworld.net/features/transworld-motocross-race-test-2005-suzuki-rm250/ . When looking at different aftermarket cranks(crank only without all seals and gaskets) those are labeled to fit 03-08 so I cross my fingers that the crank form a K7 will fit, I'll know in a few days when it arrives.

The different bearings for the different years has same ID, OD and width, but from 05 they added tabs with countersunk screws to keep them in place(see attached picture from a K7 case) and the bearing therefor has a cut on one side to give space for the tab. I have the 04 case with no tabs so I should be good with bearings for K4.