I have a freind who recently aquired an 06 rev3 250. This bike runs a little soft. It has had the clutch side flywheel removed. She said that she had someone test the compression and it was 150psi. what i would like to know is two things. How many psi on a compression test should a fresh 250 make at sea level and at 6000', and is this year engine notorius for soft power, maybe because of the ignition curve? I have a fresh 01 rev3 250 which feels almost twice as powerful and it has the clutch side flywheel still installed.

Edited September 4, 201114 yr by Liviob

Livio,

150 psi sounds about right. Taking these readings can be a bit iffy! Readings may vary by the accuracy of the guage, the conditions on the day and the method. Temps and altitude can make a big swing in readings.

Standard day(65f) sea level starts off at 29.92 in/hg(14.7psi) atmospheric pressure. Go to 6k ft and you will loose roughly 6 in/ hg(or 3psi)of air. Adjust for density altitude(temp change from standard). So on a hot day, you may be essentially riding at an 8-9k ft. elevation density altitude. Resulting in big loss of power!!! Take 9 away from 30 to estimate your percentage of loss on a hot day at that altitude! Almost 1/3 of your air is GONE, along with your Power!

Multiply by compression ratio(which we do not know) and you will get a(ideal)result based upon no intake loss in restriction.

I think they made a lot of changes in that year range to get the bikes to run on standard fuel(compression ratios, head designs) and may have changed some porting as well to tame them a bit, you would need to ck part numbers to see, I would think.

I went to the american beta website and the parts fish said that 00-02 used the same ignition then 03-05 used the same ignition then 06-07 used the same ignition then 08 had its own ignition then im guessing 09 and on have a different part number. Did the 07 run soft like the 06?

I went to the american beta website and the parts fish said that 00-02 used the same ignition then 03-05 used the same ignition then 06-07 used the same ignition then 08 had its own ignition then im guessing 09 and on have a different part number. Did the 07 run soft like the 06?

I would look at the cyl and heads as well, because reguardless of ignition system, there is only a certain range you can swing the base timing. (which you could play with) After that, the programmed advance curves may differ, yet again within limits not too much I would think.