Will a crf230 11.1 piston be ok in my cb250 engine?

**gusmanxtr** · 05-31-2013, 01:21 AM

Thanks for the link MJH. Can I use this piston without a new cam? Some people say using one without a performance cam can lead to a power loss. Any thoughts?

**magma** · 05-31-2013, 09:02 AM

you want more compression? trust me. do it in the 3 following steps.
1.you can remove 1 mm from the head cylinder.
2.you can use a thick piston that might cost a lot.
3.you can use a big bore piston that not only increase the compression but also increase the displacement.(ask me if you don't know why it happens!)

actually compression ratio tells about how many units of air and fuel had compressed into one unit. for example 10:1 compression ratio means that 10 units of air have been compressed into one unit.
more compression means more power...when the mixture is more compressed it means that you have a more powerful and effective combustion.
but notice that high compression can cause a problem i call it "kick". when the gasses are compressed the temperature raises and in a high temperature the mixture will ignite before the spark plugs.
this can cause serious problems in engine and is known as a kick sound from the engine.
to solve the problem for high compression engines a fuel with higher octane should be used that can stand against high pressures.

**gusmanxtr** · 05-31-2013, 02:32 PM

Thanks again for more comments. Magma, I don't want a big bore kit as I would need case machining, crank shaft etc and would add up to too much money. It's either going to be a head shave or high comp piston. Is a cam upgrade required for either of these or will I get more power than the way it is now without it whilst not damaging the engine?

**gusmanxtr** · 06-03-2013, 01:54 AM

Just for anyone else out there thinking of doing the same thing as me I got some crf230 stock piston measurements from a dude off thumpertalk and the comp height is different by 1.5-2mm. The crf piston's height is less than mine so I'll have to go with Magma's advice and get the head shaved.