xr400 jetting

[Johnboy]

I just picked up a nice 00 XR400 that is mostly stock. The snorkel is removed, but otherwise stock. Jetting is 138 main. Does this sound right? I'd like to set it for about 8000 feet but will go as low Moab (~4000 feet). I'll be replacing the stock exhaust baffle with the bigger one from Honda soon.
Also, what position should the clip be in? What pilot should I run. Kick starting the bike is a bear and likes the choke somewhere between half and full.

Thanks
John

[DiscoG8S]

For 4000-6000 ft. drop the main to a 170.drop the needle 1 clip and set the fuel screw at 1 1/4 turn out.
Above 6000 ft. drop the main to a 168 drop the needle 2 clips from stock position and set the fuel screw at 1 turn out

[mtntj]

Set your bike to run at 8000', this is middle of the road. It should then be good for about 5000-man it's hard to breath up here. I can't tell you how to set up for this, but I can tell you this will work. I an02 Honda Rancher 350ES, and an 05 xr650r. Both are set up on this method. Works out very well!!!:thumbsup: :thumbsup:

[Sonic Reducer]

are you on thumpertalk? there were some good threads on there recently about CO XR4 jetting. i think people were recomending around a 150/50 or 152/52 main/pilot.
I too have a mostly stock 01 XR400 soon to be plated. it's got some loud aftermarket exhaust end on it, and I just ground out the header welds the other night. I'm planning on doing all the rest of the gordons mods too.
instead of buying the honda baffle, you can drill holes in the stocker.

[Johnboy]

I have the 150/50 combo and I'm not impressed. I'm trying a 14T CS sprocket (15T on now). That will clearly bring the gearing back to what I'm used to. But the off-idle throttle response is HORRIBLE! It bogs and dies way too easy. I'm told a pumper carb is the solution but I don't have the couple hundred to spend right now. Any suggestions to improve things?

[Johnboy]

I rode Moab this last weekend and the 150/50 jetting seemed to work much better there - telling me that I need to lean out for Colorado elevation. I'm probably going to go down 1 size on both jets.

My previous bike was a KDX 220 which people compare as similarly fast bikes. NO WAY. This XR is F'ing FAST! It is that fastest XR400 I have ever ridden (faster than one that had a cam and exhaust) and it kills my KDX.

Of course we are talking about sand washes, boulder fields and slickrock style trails, not MX style fast.

I just thought I'd share since I'm still grinning ear-to-ear about the weekend.

John

[co84rc]

thumpertalk.com is the place to go for all your thumper questions.