01 400ex Wont Start.

[ONSTRIKER]

So.. I got this 400 the other day for 500 bucks needed a new piston and sleeve.. Anyways.. I just bought a stock piston and jug off ebay and put her back together with a new top end gasket set...

Now I go to start her up and she will turn over real nice but she just wont fire up... Checked the plug and its got fire.

Any suggestions?

[matt14c]

Did you put together properly? Were the timing marks set and the cam put back in properly? When you put back together did you re-adjust the valve lash? Is it getting fuel?

[ONSTRIKER]

Getting fuel.. Check
Timing.. I'll recheck
Valve Lash... No

[matt14c]

You may want to set to top dead center and then pull the head cover off. There are two lines on the cam sprocket that line up with the head. Also the cam lobes should be facing down. You could have put the cam in backwards which would have the valves opening at the wrong times. If your getting spark and your getting fuel and your timing is correct then im not really sure thats the extent of my knowledge.

[IndyNate]

IM in the exact same situation right now. i think mines the timing also. mine seems like its cranks too fast

[matt14c]

Cranks to fast? Have the right battery? What was it doing or what did you do to it? If its cranking to fast you maybe dont have any compression.

[IndyNate]

resleeved and bored to 440. it seems to crank fast. also we noticed we couldnt get the chain to line up right with the marks. its a used white brothers cam and with the top off we can move it back and forth some. should it be able to walk like that???

[matt14c]

Im not sure with the big bores if your running an hot cams stage three or similar in the white brothers if the timing is delayed or advanced.... Im thinking though the lines on the sprocket should still line up. Pull the chain up with some tension with your fingers and take the plug out then rotate the crank by hand to make sure its not bound and its on the sprocket. Again when putting the cam back in the lobes need to be facing down. Check for fuel. Check your compression.

[mcgrath]

If you have fuel, spark and timing on, it will start. It might not run well if you have the jetting off or carb problems, but it should start if you have the fuel, spark and timing right. Id recheck the timing, you could have it 180 degrees off. It would still turn over but not start.

[ONSTRIKER]

Well now that I think I have the timing right.. She will pop and fire but wont get all the way started

[mcgrath]

Does it have bent valves? Maybe they arent closing.