Will a 2003 cr250 rev quicker with a 92-01 crank

98zx9r

Member
Sep 1, 2006
3
0
I have read that a 03 cr250 will rev quicker if a 92-01 crank is installed. They said the 03 crank weighed more. Then I read a guy orders a 01 crank and weighs both and the 01 was slightly heavier. Is the weight closer to center on the 92-01 crank? I have a good 01 crank but this is a lot of work to find out if there is a difference. Has anyone tried this and can you explain the difference in cranks that allow it to rev quicker.
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Never heard of anyone making that change. Seeing as the '02 was a complete redesign, I'm very surprised the '01 and earlier cranks will drop in to an '03.
 

98zx9r

Member
Sep 1, 2006
3
0
Thanks for the replies. The reason i'am asking is I have a 03 frame that I put a 01 engine in a few years ago, and the 01 engine hits hard making it difficult to handle at times (being 55+doesn't help). So I was thinking of going back to the 03 engine to get the smoother power delivery but in general I like good low end and mid and the 03 seams a little sleepy down low. Looking at dyno runs from shoot outs the rc valve motors usually show more power down low but sure don't feel like it. Is this because they have a heavy or high inertia crank or did honda go for traction control with the ingition mapping, or something else? Anyway thanks again for the replies.
 

High Lord Gomer

Poked with Sticks
Sep 26, 1999
11,790
34
Do you have the Mikuni that came on the 01 or a Kehien? I had nightmares trying to get the jetting right on an 01 and was very happy when I switched to a Kehein.
 

98zx9r

Member
Sep 1, 2006
3
0
I have a keihin from a 2000 on the 01, a rad valve, srs piston, and fmf fatty pipe. I also have a fmf gnarly, and stock pipes. I tried somethings this past week with the power valve, added small spring to delay opening, adjusted to open about 3/4, went back to stock setting and tried the gnarly which seemed to help. The gnarly feels like it pulls a little better down low and not as much on top. I also tried a small flywheel weight but didn't notice much difference with it.
I think I can get rid of some of the hit by going back to a oem or wiseco piston but I don't see getting this engine where I will be 100% happy with it (my 96 cr 250 had close to perfect power for me). I may just put the 03 engine in and see how I like it.
Thanks again for the reply and suggestion on the carb.
 
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