[Carbon400ex]

I all, i just bought a 04 400 EX in mint condition the other day and i was just wondering if it should be rejetted with a K&N air filter and a yosh slip on? The thing starts up and runs just perfect with no poping on deceleration or anything but i just wanted to be on the safe side. I was also wondering how many gallon the gas tank would be. Thanks alot!

 

[t-rex]

you could jet up see if it runs better if its not popping it shouldnt be lean.

 

[Helmut]

I all, i just bought a 04 400 EX in mint condition the other day and i was just wondering if it should be rejetted with a K&N air filter and a yosh slip on? The thing starts up and runs just perfect with no poping on deceleration or anything but i just wanted to be on the safe side. I was also wondering how many gallon the gas tank would be. Thanks alot!

When you bought it, did it come with the K & N filter and the slip on already on the ATV? If it did, maybe it's already been jetted. I would pull the spark plug out and look at it and see what color it is. It should be a light brown or tan. If you just added the parts, then I would put a new plug in it and do the plug test.

Fuel tank capacity is 2.6 gallons.

 

[TRX2fiveO]

Agree^^^^^ check the plug first.

 

[Carbon400ex]

ok thanks guys. Would the best way to cleck the plug be to just ride around then check it or do a plug chop like shut it down at like full throttle and then do a half throttle check??

 

[t-rex]

ya just ride for awhile then check.its not lean so should be alright.