so if i bought a new after market exhaust on my 400ex would i need to get it rejetted?

 

As restrictive as the stock Honda exhaust is, I would say yes, best bet with the 300-400 ex is to go up one size on the pilot jet,it will start and idle better that way, and with an exhaust, you are looking at 1- 2 sizes bigger on the main, depending on if you get a standard quiet core type, or a full flow race can. To get the most from the exhaust, you need to supply more air, so a good aftermarket filter, and maybe a modded airbox lid, or running an Outerwears cover to let in the most air and still keep out the chunks of dirt, you may need to go up 2-3 sizes on the main. Once your intake/exhaust mods are done, and you rejet, make a couple of plug burn runs to check the plug color, get up to speed, then hit the kill switch and pull in the clutch and let it coast to a stop, do not decel or let it idle. then pull the plug (let it cool or wear glove--hot !!) and check the color of the plug, looking for a nice cardboard brown with no black or white areas.

 

No, you dont have to do anything! If you put a new air conditioning unit in your house should you buy a new compressor? New exaust cat back, should you go threw with headers? Ww2 should we have just did it ************ rigged or finished it.... Yea u need jet kit!

 

Yes

 

Oh, man thanks for clearing that up! : )

 

well i have an after market exhuast on there already. and i have a uni air filter with the air box lid off but i dont know if the jets have been played with i just bought the bike about 2 months ago.

 

Pull the spark plug, if it's white you need to rejet, if it's tan or brown, you're good, if it's black, you're to rich.

You're such a great help pimple.

 

New pipe=rejett

 

okay thanks!