I just purchased a 2000 Explorer 400 and would like to increase the performance.I would like to
stay away from adding a pipe but I'm open to anything else.Mainly looking to get more jump
coming out of corners without hurting top speed.

 

I put a polaris purple spring in the primary clutch and set the secondary clutch to 17lbs preload on a few 400's. The purple spring will come in at a little higher rpm but it shifts out at the same as a stock spring. Resetting the secondary will keep the rpm's up when come out of the corners.

 

K&N filter woke it up a little in the mid range. Gained 2mph hour on top end, 62.3 compared to 61.1 according to my gps. I'm basically in the same boat, want more but without the noise. Was thinking about replacing the reeds with boyseens. I don't want to clutch it till I'm through playing with the motor because if I do decide to pipe it it'll need it again. Goodluck!

 

the only difference I noticed with the boyseen reeds was better gas milage. I did pick up a little on the bottom and mid with a reed spacer

 

I put an EPI clutch kit which gave it a lot of extra acceleration and better feel. To me it feels twice as speedy as it used to!

 

Did you gain or lose top end with the kit?Thats the other problem with modify these machines is a guy better off buying a complete package from one company or piecing together your own from a varity of companys?

 

When I purchased the clutch kit the mechanic told me that I would loose a wee bit of top end but get more low and mid-range performance...which was fine with me at the time. After riding a while, I noticed hardly any loss in top speed...but then again I don't ride at 60MPH on the trails up here. Recently though, before getting my 26" tires added, the mechanic at my new dealer reluctantly told me that he tested my bike on the entryway and got it up over 62 MPH. So according to all this my quad basically stayed the same.
One thing I did notice with the clutch kit is the following: On hard packed snow my rear tires seem to have more power than the front causing them to spin out a bit more( back and forth)...this is when I hit the throttle all the way in going at around 30 MPH. On dirt and others it is great though!

I hear that a hot set-up is a Clutch kit with new air filter and V-force reeds. No more noise than stock and doesn't touch your warranty. Thats what I am putting on my Scrambler400 tomorrow. Maybe next for the Xplorer400.

Good luck!! I even think they make a performance Clutch kit for the 400 too...??

 

Thanx, for the info. I've been thinking about a clutch kit but wanted to figure out and complete my motor mods first. I'm considering some trail porting, I've heard this will give you the power of a pipe without the noise and won't hurt reliabilty. I was thinking about just replacing my reeds with aftermarket ones. How about Boyseen reeds I've heard they are longer lasting than Delta's.

 

You can pick up 5% more top end by changing from the 36 tooth rear sprocket to a 34 tooth

 

When you switch rear sprockets do you lose that much power?? Also isn't that smaller sprocket you are talking the one that came on the 400 sportsman?? Do you have to shorten up your chain when you switch sprockets?? How much does that sprocket cost?? I think that this sounds like something I might try Thanks for the info