ive got a 400ex with white bros e series pipe and kn filter running a 150 main jet .... does anyone have any tips or anything else i could do cheap that could help me, such as removing disc from pipe because ive only got 9 in now.....i drag race allot and my bro has an fmf megamax 2 and kn filter and i can beat him but he beats me more times than i beat him....its hard for me to leave in 2nd and i want to stay same gearing...however i almost beat a banshee stock the other day..he only beat me a bike ....and i beat a 405 ex which was a 300ex stroked....any help, tips , or tricks would be helpfull, thanks!

 

150 main jet with a pipe and filter? That's only one size up from stock. Sure you're not running lean? Unless you have a dynojet kit, I've heard they have a different sizing system.

 

I agree, I'd be running at least a 155 main with those mods. Also, the E-series manual says the EX makes the most power with all 12 discs in (and a 165 main with the airbox lid off).

 

well i have the slip on, and it says you really dont have to change the jet but i still went up one and its running good....is that what yall where suggesting for the jet? thanks

 

You really, really, really need to read the tech connection section of this website - it will tell you exactly how to jet your EX. Click on the tech connection on the main atv connection page, then click on advanced search, then select carburetion/jetting as the category and leave atv model as All Models. Now, Read all of the questions regarding rejetting - it doesn't matter what machine they're talking about - it all works the same. Not only will you now know how to rejet, but you will learn why it is so important to do it correctly. The EX is quite easy to switch jets in, it won't take you long.

I have learned that the pipe companies recommendations are usually off, often way off - do yourself a favor and learn, that way you won't burn up your machine.

As an example, I just got a supertrapp ids-2 slip on (soon to have K&N filter too) for my 400ex. As of tonight, I'm up to a 162 main jet and still no rich burble at full throttle (you'll understand what that is once you read the tech connection). That's six sizes bigger than stock - with just a pipe; you're only one size bigger - that may be dangerously lean. After you're done reading, go to the local dealer and get a full complement of main jets - from 152 to at least 165 - they don't have to be from honda ($$$), just bring in your jet and match it to a kehin jet - then, get to work.

 

just a quick note, I got the rich burble at 168, none at 165 - so that's where its set at. The needle was raised one notch, did a plug chop, and it looks perfect. On a side note, that ids 2 race pipe is LOUD. I keep dropping disks to quiet it down (its at 7 disks now) and is still loud when you get on it. I just want everyone to know, cause some people here don't think its not that much louder than stock. True, when its idling and when you have constant throttle its close to stock - roll on the throttle, she BARKS. Is there a quite series baffle for the 400ex ids 2 pipe?

Thanks, ogre

 

The SuperTrapp IDS2 Racing Series is definetly loud! My friend had one on his Lakota until he snapped two of the bolts that hold the discs in, and man, when he gave it throttle, it was amazing. Great sound, but too loud. I'd spend the extra money for the Quiet Series. Less sound = more ground.