'03 400ex Running horrible after rebuild

[BOEN]

About 2 weeks ago i tore down the top end of my 400ex for new top end gaskets.(bike was running before this)) I made sure it was in time before i put it back together, timing marks even with the head and the T mark in line with the index mark, i have hot spark, getting plenty of fuel, and it has compression. It will start if its fully choked and i give it throttle, but it will not idle by itself, ive cleaned the carb, still nothing.

Im stumped, i think im over looking something simple but i have no idea what it could be..
Any help would be great :confused:

[Stickman400]

Make sure the pilot jet is clean and isn't clogged, check and make sure the a/f screw is turned out around 2.25 or 2.5 turns out. Also make sure the idle screw is touching the throttle arm and moves it when you adjust it, it may have got moved when you cleaned the carb. and isn't even holding the throttle open when you let off the gas.

EDIT: whoops, just got home from work and re-read my post and notticed I said make sure the pilot jet is clogged, obviously I meant isN'T clogged.

[CJM]

Check for exhaust leaks (put your hand over the pipe when you get it running and leaks around the gaskets, and the carb boots/airbox and whatnot. I know the crush gaskets on the head should be replaced everytime pipe comes off.

its an airleak of some kind possibly.

Also I concur with Stickman, clean the carb out too.

[on the rocks]

did you hone the cylinder while it was apart? any time the cylinder is separated from the rigs it needs to be honed.

ohhh yea and did you make sure you didn't lose the cam decompression plunger?

[BOEN]

im going to clean the carb in a little while and see if it will help. i never pulled the cylinder, just the head.

[BOEN]

Also has a hotcam, not sure what stage, ( doesnt have the deconpression pin or lobe for it) i bought the quad with mods already done, all ive really done is a barnett clutch, and full sparks exhaust, i was told the engine had a 426 wiesco kit

[JOHNDOE83]

Your gasket kit may have changed something compression wise, it is possible that your jetting and timing are slightly different now.

Try to turn your A/F screw out to 3 or 3.5 turns and see if it acts any better, just for a test not a deff answer.

[BOEN]

FINALLY got it started! cleaned the carb, reset the A/F screw to 2.5 out, and reset the timing one more time for good measure, hit the button and it fired right up, NOW, whats the proper way to adjust my valves?? i have just a little bit of clattering in the top end.

[CJM]

http://www.atvriders.com/articles/valveadjustment400ex.html

[BOEN]

i adjusted the valves and played with the idle and A/F a little, and seems to be running great.

Thanks guys!