Okay you guys, I'm going to do some motor work pretty soon on my 400EX, and I've compiled a list of things I'm going to do. Here they are:

*JE 10.8:1 or 11:1 piston
*XR400 cam
*mild porting
*boring
*carb mod or FCR (will come later in the future)

I don't really want to overbore much, but if I do, I think I'd probably be comfortable with a 406. What I need to know is, with a 416, will you see a bigger increase than with a 406? If I'll gain anything worthy, I'll go to the 416, but if not, I'll stay with a 406 or less. Please help. Gabe, your opinion is greatly appreciated. Thanks.

 

The 406 will be fine, the HP increase from going to the next overbore should be negligible and the piston should be lighter in weight - as long as you can get the compression ratio you want. That was my problem, with the JE pistons, the 10.5:1 in 86mm and 10.8:1 in 87mm are the ones that are readily available, I wanted a bit more than 10.5:1....

If you're wanting more top end, I'd spring for a more aggressive cam than the XR.

One of the fastest combo's I saw over the weekend at Little Sahara over the course of watching several hundred sand drags was a 406EX running a WB "race" cam, FCR 39 carb, and a WB R4 silencer on what looked like a stock header pipe. He was consistantly outrunning modified DS650's, modified Raptors, modded 250Rs, and even many worked over Banshee's - even pulling them if they holeshot him. Pretty impressive for the money he spent.

 

Gabe,

Does the XR400 cam give a good power increase at mid? I'm looking for some more power for the MX and SX tracks. So, I need a little bit of power everywhere in the powerband. I think I may just stay with the stock bore for now. I'm just not comfortable with boring my cylinder yet. I can only get a 10.5:1 JE piston. Is this going to give quite a bit less power than the 10.8:1 that you have? Also, what is the part number for the XR400 cam? Do you know? Also, is $131 for the JE piston, rings, pin, and clips? Thanks a lot.

 

The XR cam is just a small step up in aggressiveness from stock. Don't expect miracles from it - provides a little more mid. I am very happy with my setup & fuel economy for woods racing - if it weren't for that, I'd go for a more aggressive cam in an instant - probably will order one for testing anyways.....

Yes, the piston includes rings, wristpin, and clips.

XR cam part number: 14000-KCY-670

 

Gabe

I'm planning a Lil Sahara trip May 11th. I've heard good things about the place. How did you like it? I was told paddles are a must. Any special rules a first timer might need to know?

How did your 416 hold up against the drag crowd?

Jay

 

It was my 4th trip, always a blast.

The 416 did well, it would have been one of the fastest 400's there if I had a more aggressive cam for more top end. I did outrun the piped Raptors (got the holeshot and was able to maintain about a bike and a half lead) and various other bikes as it sits though. I spend most of my time either jumping or tearing around in the sand trails though.

The biggest thing to look out for is the razorbacks, you can fly off one in an instant if you're not paying extremely close attention & receive a free ride in the ambulance buggy... Not a cool way to exit the dunes... Had a couple of buddy's do that this trip and it was a pretty scary ordeal for about 30 minutes until the one started to get feeling back and regained control of his limbs.

Other than that, just use common sense, look before you leap (literally), and watch out for the buggy's (they're much bigger than us and aren't too terribly concerned with us).

You'll need a flag - stop by Jim's sand toys and pick up one of his $19 units with a lifetime warranty (they're well worth it).

No, paddle tires aren't necessarily a must, but if you plan on doing any drag racing they're a pretty good idea. A set of Holeshots, or similar in good condition will get you around fairly well... Of course, paddles will get you around a bit better, especially if the sand is dry.

 

the lil sahara is the best! i have ever been to at least. i was there easter weekend! was any one else?