KX 250 / BLASTER

[stroking]

OK IM BUILDING A kx 250 motor to put on a blaster frame....drag only bike,now i have two cylinders,but one is a 2003 the other a 1995 the 95 has alot bigger triple exhaust ports than the 2003,now which of the two do you think will make the best drag cylinder ?

 

look at the difference in size of the ports

 

 

both intake look the same

 

[stroking]

also i'm thinking about removing the power valve and epoxying the open spaces up.

 

now would that be a good idea or should i leave the valve in ?

 

this valve closes the triple ports and makes the exhaust port smaller when it is at idle and opens at higher rpms,but my cub looks the same except for the power valves and it runs hard so im thinking the power valve will slow me down some.

 

what do you think ?

[01banch]

I think I would leave the power valve it will give you easier launches and open up towards the end.

[sleeper06]

When you drag port a power valve motor be carefull of clearances you can have a piston kiss them,stick with the cylinder with the square port it looks less hacked,the valve changes your ex duration when not wide open.My friend has a drag ported kx 250 motor ,we left the powervalve in the motor with no problems his motor runs hard.how far are you running might need desert gears

[RadarRacing]

You can leave it in. It should be closed below about 6000 or so then it should open completely at high rpms. It should not slow you down in any way unless it doesn't open.