Hi,
03 LTX 400 will not start cold,
It has good spark
Pop the clutch and it will fire right up
once it is warmed up it will start no problem
Starting fluid into carb does not help
CDI and coil test good
what should I try next?

 

Did you try starting it on "Prime" then flipping it over to "Run" after it warms up?

 

Yes,
it does not help

 

more than likely you intake valves are tight , get the valves checked

 

Had that done in July of this year.
The bike use to start no problem and then is slowly got worst
How would valve adjustment make that much of a diffrence?
bike has very good compression (135 to 140 psi)

 

not to steal your thread but ive got the same problem, bike is stock tho.... 03 model as well.

 

If you pop the clutch will it start?

 

because i had the same problem with mine . push it and it would start ,when it was warm it would start , adjusted the valves and no more problem. if you dont have a shim kit at least try and see if you can get a feeler gage to slip in or not, then all question is gone.

 

Cataway made a good point , check the valve clearance. I have seen too many people towing their atv's around trying to get them started.

 

if the valve don't seat (out of adjustment), would it still have high compression when cranking?