New 400ex owner - Few Q's

[nickthompson77]

Hey. My girlfriend just purchased a new 400 yesterday. What are a few good 1st mods to help out for a power increase. We will be riding at Glamis all season. I was thinking of getting her a uni filter and running it w/ the airbox lid off. Do I need to purchase the aluminum adapter with it? Any suggestions will help. Thanks guys.

[K_Fulk]

Thats a good start. You dont need the aluminum adapter for the air filter though. Next step get a pipe, carb or motorwork.

[Martin Blair]

a good filter and a pipe, i lik my lrd full system pulls hard threw the midrange, if you dont want to spend alot a t-4 or a e series is a good slip on.

you can take your choke out for free.

spend some time on the jetting a stock motor with a exhaust and filter has alot of power when jetted right.

also change gearing to a 14t front.

then work on suspension.

[nickthompson77]

So, a "slip on" is just the silencer right? Would you recommend just the slip on or get the header and the silencer?

[86atc250r]

Check the throttle adjustment. I'm still seeing tons of 400's out there with the adjustment screwed all the way in, which will kill top end power. Easy, free power by checking something you're supposed to check periodically anyway....

[Martin Blair]

yeah slip on is just the silencer, well i do woods racing and run a lrd full system but lrd is the only full system i would run in woods racing all the other full systems giuve you top end and take away bottom, i cut 2 inchs of my lrd as well whihc give it a little mor ebottom and a little more noise.

It really depends on what you want a slip on will give you good otrque low end and midrange but not to much topend, the lrd fullsystme gives alot of midrange and when i removed the choke the lrd pulls hard threwout the whole powerband, but they are expensive at near 500 including a sparkarrestor.

If the bike is goign to be ridin alot just on trails and rec riding not racing i would get a slipon (just silencer) again some good slipons are the t-4, e series, and hmf . If it is goign to be raced i would use a lrd or hmf for woods, sparks for drag racing, and for mx lrd, sparks, and hmf are good if you can keep it where it has power.

thats the rest of my 2 cents go to faq to see how to remove the choke.

also check the throttle cable mine wasnt opening all the way when i first got it and it killed the power.

[nickthompson77]

Where is the screw located for throttle adjustment? Thanks everyone!

[86atc250r]

At the thumb throttle assembly, where the cable exits.

[nickthompson77]

Thanks....Found alot if info on the throttle adjustment. Also, my girlfriend has tiny hands and it is quite a stretch for her to pull in the clutch lever. Is there a way to adjust the lever so it is closer to the grip? Thanks again.

[86atc250r]

Yes, there is an adjuster at the clutch lever where the cable comes out, much like the throttle.

Personally, I don't like it when all the slack is taken out and the clutch pull starts at the furthest most extension of the lever either.

When you adjust, just make sure the clutch fully disengages when pulled in.

[nickthompson77]

Right on then...thanks.