[fish-d-fish]

we just finished assembling an 08 crf 250r with the following info
weisco cam
stock crank
stock ignition
weisco 13.5:1 piston
40mm stock carb Bored to a 42.5mm
kibble white ss valves and springs stock size
stock leak jet
stock needle
pilot 45
main 185
ported head but not decked
elevation is 600ft above sea level
titanium single pipe exhaust
decompression arm mod

**this motor is in a trx 450 chassis with a cut back custom exhaust from a ktm 450 with a K&N cone filter on it.

Here is what we have went over; first, the quad ran very well with a stock motor all last year in the quad frame with the intake set up and stock bore carb.
timing has been carefully checked 5 times using marks on the cam and right case side indicators, also using the marks on the flywheel(just learned that they are useless without a timing light but the others are dead on), we have really good spark and have tried a whole new harness including stator. we have checked valve clearance 10x. they are .006 and .011. with the intake off we have good strong pull on the carb. accellerator pump is spraying right into the port. The basic problem is that it will not kickstart. out of 100 kicks it might sputter 2x. If I drag it I can get it to start but it runs horrible(not clean) and you have to hold the throttle almost wide open to run at all. 3 days into this thing and not sure where to go!
A few basic questions:
what are the signs of an over ported head?
Should the motor fire up even if the plug is wet or are the crf's that tempermental?

Help! and thanks Brian

[riddler9]

If you give it too much fuel it will not start - hand off the throttle when kicking it.

Sounds like you should check compression / do a leak down test.

Not sure what you are looking for with the over-porting. If they wen too far then you will see the valve guides. More likely a bad port than an over-port.

Any chance someone polished the intake side of the head? If you polish the fuel side the gas and oil will not spin. Everything just slithers down the port and the engine runs like $h!t.

[fish-d-fish]

They did not polish the intake side, they scuffed them up nicely and gouged them a few time to create turbulence. You can't see the valve guides either. tried the stock carb today with jetting all over the map and got it to kick start but it would not run well at all off idle. 45 pilot,55leak, 185 main..ugh