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400ex wont start up easily
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Posted by: dripinc09

I have a 1999 400ex. Just got it last weekend. It doesnt start up very easily. What should i check ? My only thoughts were check the gap between the lifters and valves? I know i had the same problem on my moped last summer. It turns over just fine, just doesnt seem to fire. But every once n a while it will.

Posted by: BakerRacing40

after it starts does it run good? check your plug and see what it looks like and if you have a multimeter check you battery while your cranking it, it might be trying to crap out on you. i know that some 400s just crank slow.. not sure what you can upgrade the battery to?

Posted by: dripinc09

It rolls over fine. Once its running and warmed up it runs good. All day sunday i couldnt get it to start. but saturday i drove it for an hour.

Posted by: mattonln

check your valve clearances, thats the number one problem with starting and idling issues on 4 strokes.

Posted by: f4iracer

do you use the choke? Just start it up with the choke on and run it for like 3 or 4 min. with your thumb on the throttle.

I have to keep mine running with the choke on for a couple min. before i turn it off. and then i have to work the throttle. I like to start mine when i'm ready to take off so it warms up alot easier. Otherwise, i've gotta be on the throttle for the first 5 min. of warmup.

Posted by: speedfreek

Go up to a 42 on the pilot jet! This helps with cold start ups.