Jump to content
Sign in to follow this  

HI compression gasket 03 cr250

Recommended Posts

I want to make a top end job to my 03 cr 250.

My question is if the Hi compression gasket (the cylinder one) will make my bike run better, i mean, more power.

Thanks!!!.

Share this post


Link to post
Share on other sites

I bought the Moose Hi compression gasket kit.

The base cylinder gasket es 0.012" instead the 0.020" OEM.

Will my bike run with more compression and power???...............I looking for a boost in the low end range.

Share this post


Link to post
Share on other sites

I'd stay away from it. This bike already has too much compression and detonates badly on pump fuel. From experience, raising the compression is not what it's cracked up to be. It narrows in the powerband and requires you to use exotic race fuels. Do it only if you know a tuner that will machine the head to compensate.

Share this post


Link to post
Share on other sites

I'd say do it, but know that 0.008" isn't going to make a huge difference.

This bike runs less compression than any other 250...the reason they detonate on pump fuel is because of the large squish clearance they're blessed with when they leave the factory. The hi-comp gasket kit will raise the compression to approx. 8.85:1 CCR which is still lower than any other stock 250.

Share this post


Link to post
Share on other sites

What do you think???......with 97 octane fuel i will be ok with detonation?????

97 is the higer octane fuel in my country.

Share this post


Link to post
Share on other sites

i run the cometic thin base gasket in my '96 in combo with .018 taken off the head and did notice a pretty significant difference. i run premium pump gas mixed 40:1 and don't have any problem with detonation

Share this post


Link to post
Share on other sites
What do you think???......with 97 octane fuel i will be ok with detonation?????

A stock bike with 0.008" off the base and 97 (RON) octane will be fine if your jetting is correct.

Share this post


Link to post
Share on other sites
I bought the Moose Hi compression gasket kit.

The base cylinder gasket es 0.012" instead the 0.020" OEM.

Will my bike run with more compression and power???...............I looking for a boost in the low end range.

I used the Hi comp. cometic gasket on my 03 & it did help the lowend. I ran 91 octane at 32:1 with no problems. As some one stated on this thread they are the lowest compression of the 250's. :applause:

Share this post


Link to post
Share on other sites

Your going to get tired of running race gas if you have to, stay away from it if you can! I have to run 110 undilluted and its 7 bucks a gallon! Gets old REAL quick.

Share this post


Link to post
Share on other sites

thanks, i will try the hi comp gasket with 97 pump gas.

I will let you know if i feel improvement in my engine performance.

Share this post


Link to post
Share on other sites

just wondering, what is the best gas to run in my cr250? i currently run 93 octane, i dont kno wwhere in my city has a higher octane for pump gas, what gas station chains in your area, sell higher octane fuel? we have roughly 18 different gas stations within a 3 mile radius of my house, so im sure someones neighborhood gas station that has higher octane fuel, i snear me, thanks guy's.

Share this post


Link to post
Share on other sites
just wondering, what is the best gas to run in my cr250? i currently run 93 octane, i dont kno wwhere in my city has a higher octane for pump gas, what gas station chains in your area, sell higher octane fuel? we have roughly 18 different gas stations within a 3 mile radius of my house, so im sure someones neighborhood gas station that has higher octane fuel, i snear me, thanks guy's.

Well here in California, at least where I'm from, the highest pump gas you can but is 91 octane. I have to go to a race cart shop and buy my 110 octane gas, thats why it's 7 bucks a gallon. Where I live, there is not actual pump station that has high octane gas.

Share this post


Link to post
Share on other sites
It narrows in the powerband...

Is that true?

I purchased a used 2002 CR250 a few months back and the previous owner had "shaved the head" 30 thousandths. I really dont know how this bike is supposed to ride stock but mine has an incredibly hard hit but the power seems to be narrow as you describe. I am always short shifting it to stay away from the hit when I am in the woods.

I am thinking of doing a top end to freshen the motor and want to know if you guys think I should replace the cylinder head with a new OEM head and if that would widen the powerband at all?

Thanks!

Share this post


Link to post
Share on other sites
Is that true?

I purchased a used 2002 CR250 a few months back and the previous owner had "shaved the head" 30 thousandths. I really dont know how this bike is supposed to ride stock but mine has an incredibly hard hit but the power seems to be narrow as you describe. I am always short shifting it to stay away from the hit when I am in the woods.

I am thinking of doing a top end to freshen the motor and want to know if you guys think I should replace the cylinder head with a new OEM head and if that would widen the powerband at all?

Thanks!

Originally Posted by no hand

It narrows in the powerband...

i don't think thats true, when i had the head shaved on my '96 it enhanced the powerband everywhere(especially down low). something to consider though, my '02 has a very brief powerband and i've heard other guys describe their '02s the same way. it might just be the nature of that beast, personally i can't stand the way my '02 runs thats why i'm still riding my 11 year old bike because it will smoke the hell out of the '02 in every way other than suspension.

Share this post


Link to post
Share on other sites

Increasing the compression is more often a big hype. I've had many engines modified and sometimes even the compression was reduced. The one time I tried increasing compression by shaving the head I wasn't too happy with the results. It gave more low end but lost some overrev to compensate. I realized it is pretty easy to mess up a perfectly fine engine.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×