Honda 400ex - Help

[coltonisballin420]

i ride a honda sportrax 400ex, so yesterday i was riding my quad with my buddies down there road. and we decided to gun it. but when i pushed in the accelarator i noticed my quad wasnt going any faster. and then it started bogging down real hard and i heard a loud noise from my quads engine. now when i go to start it up it turns over but wont catch and start up. what could i have blown?

Edited August 17, 2012 by coltonisballin420

[oxidized_black]

is there any noise when you turn it over? (like grinding and clanging) do you still have spark at the plug? fuel to the carb?

[coltonisballin420]

yes it makes its normal starting noise. it just wont start up. thanks for your help. im ripping the whole thing apart tomorrow to see if i can figure the problem out.

[Missouri_2004_400ex]

my buddies did that. Ended up something with the gas injector fell off to some sort.

[marioweldinginc]

Id check the basics first. Air, fuel, compression, and spark. Then if those check out id pull the cam tensioner and check chain tension. Maybe it slipped a tooth.

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[mxquadmom]

I had a similar issue on our 00 400EX...It was running fine then while I was climbing a hill it began to seem to bog down/loose compression. Next thing it stopped running. Never could get it to start but it would turn over. The culprit.... the decompression plunger. It is located on the top where the cam is (the cylinder head). There is a little spring under the plunger. I removed the plunger & spring. Clean it with carb cleaner then put back in or I completely took out the plunger & spring put the cylinder head back on. If you have a CLYMER Manual it’s on page 81. I can’t say for sure this is the problem with yours but it’s not hard to access it & it doesn't take long to rule it out. Hope this helps.