99 Cr250 Rpm limit

[310Rduner]

Anyone know the max rpm a 99 cr250 revs to? I just got a cr ignition, and I'm trying to get the right figure off a gearing calculator for my max speed now.

[310Rduner]

Tell me if this seems like it would be correct. I found a list of the offical rpms at which you would sound test a list of bikes. For the trx250R the max rpm I know is 8250, and the rpm you test it at is 3500. The rpm you test the 99 cr250 at is 4000, so I set up a proportion with those numbers. If the 4000rpm test is at the same percentage of the max rpm of the bike as the 250R is, then the max rpm should be 9428. Does this seem like a reasonable way to come to this figure?

[310Rduner]

With my gearing that would give me an over-all top speed of 88mph according to this gearing calculator.
:eek2:

[YFZ450Ridr]

all i can say is that you have advanced math skills, lol.

[310Rduner]

Originally posted by 250EXridr
all i can say is that you have advanced math skills, lol.

I'm only in trig/pre-calc next year. But that's not advanced stuff.. its like algebra 1/pre-algebra.

A proportion is this (use mine as example)

3,500 4,000
------- = -------
8,250 n

n is what you want to know, the max rpm of a cr250. You multiply 4,000 x 8250. Then divide that number by 3,500. That final number is = n. So By that I know that n (max rpm) would be equal to 9428.


Argghh numbers wont line up.. they should be underneath eachother.

[LTandRaptorider]

there was a web site that talked about getting usable power from 9-12.5k rpm! :eek: www.ericgorr.com has lots of tuning info.

[310Rduner]

Originally posted by LTandRaptorider
there was a web site that talked about getting usable power from 9-12.5k rpm! :eek: www.ericgorr.com has lots of tuning info.

Hey, Sweet Site! I'll really like looking through the 2 stroke section... but. What teh hell does that have to do with my ignition :blah: :D

[twisted threads]

were did you get your CR ignition from?

[310Rduner]

Originally posted by twisted threads
were did you get your CR ignition from?

A user on the boards had 2 for sale. They were setup by gt thunder, and come with the billet plate like esr makes. He had em on his bikes for a year, and is getting rid of the bikes. I picked it up for $250 (500 new). It's in perfect shape, and the connections are tight and its really clean; no rust or anything like that. He may still have the other one.. let me find the link. Here is the members name: Shaf1070