Im confused......

[ridehonda400ex]

Okay so im getting an HMF sport series slip on pipe for my 400ex. everything else is stock. So heres where im confused, my dad was talking to the dealer about slip on pipes and the dealer said that there is no need to rejet the carb unless its a full exhaust system. well im not getting the full exhaust. but i think the dealers are wrong

[quadrider2112]

it will need jetted i wood think and i wood go ahead and to off the airbox lid too.

[sixer3]

it definitely will need to be rejetted. whether you remove the airbox lid or not

[CJM]

Always rejet. Dealers arent all that bright btw.

I took my 416 down to the dealer after calling and they assured me they could tune it. All they did was play with the notches on the needle and adjust the air/fuel screw. I needed much larger jets and they screwed me-I paid 2x for nothing.

[Scro]

Rejet, and never take advice from that dealer.

[ridehonda400ex]

i knew i was right. worthless POS dealers.

[wilkin250r]

Well, yes and no.

Checking your jetting is always the safe road. Some quads are jetted rich from the factory just to be on the safe side, some are actually jetted lean from the factory to pass emissions testing. If you're slightly rich from the factory, you might very well be dead-on with a slip-on pipe. I've had several times I've rejetted somebody's quad for a slip-on, and ended up with the stock factory jetting.

Filter and airbox mods, on the other hand, drastically change the vacuum signal to the carb. If you change to an aftermarket filter and eliminate the airbox lid, and still end up with the stock factory jetting specs, then you didn't jet correctly.

[ridehonda400ex]

well see i think i might not have too, unless i get a k&n. because my fuel screw on my carb is all the way in. i know i should go down a size but its runs good lol so im happy

[TheLane]

i can tell you on a 400ex your most likely going to want to, going from the stock exaust to a slip on will COMPLETELY change the way your bike breathes and the amount of backpressure your getting.

You pretty much just spent a ton of money on a preformance part to make your bike not preform by skipping this easy process.

[ridehonda400ex]

yeah im gunna rejet it. i have the kit on the way and once i get into the top end with it not jetted it sputters