Colorado jetting for KTMEXC400

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Jun 11, 2001
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#1
I have a 2001 KTM 400EXC. It is a great bike. The Ebutton, hydraulic clutch, lighter weight, handling, and power make this an ultimate bike. We are planning a trip to Colorado. My question is what jetting has anyone ran there for both in the mountains and lower levels? Second question is what can I expect for mileage on this bike in that area? I do appreciate any help....
 
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Dec 22, 2000
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#2
I lowered the needle in my carb 1 position and adjust the fuel screw in or out depending on temp/altitude. I have ridden my 400 EXC from sea level to 9000 ft like this and it runs perfectly. Amazing. I currently have a MXC tank on mine and get about 80 miles at race pace or 125 miles at easy cruising per tank. I could only go 50 miles (at race pace) on the stock tank.;)
 
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#3
Jetting for Colorado

HELP....Is there no one who has ridden a KTM EXC 400 in Colorado??? I need to know what to expect there. The Canada help was a bit unusual in that I always understood that you needed to change main jets for altitude. Help me if you can, I'm feeling down......thanks
 
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#4
I live in Colorado and ride between 4-12000 feet. For 4-6000 feet I drop the main to a 170.drop the needle 1 clip and set the fuel screw at 1 1/4 turn out.Above 6000 feet I drop the main to a 168 drop the needle 2 clips from stock position and set the fuel screw at 1 turn out.After a year of riding and 4200 miles later these setting seem to work very well.Where will you be riding at? If you plan on doing Taylor Park let me know and I will be your tour guide.
 

TexKDX

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#5
peoman,

Just unloaded an '00 400EXC off the trailer yesterday. We rode at Rampart Range (approx 7800 ft) and Divide (9000-9500 feet).

The bike ran great with a 160 main and the needle clip 2 positions from the top. The needle seemed to make the biggest difference. The bike started out with a 172 in it and the clip in the 4th slot from the top and barely ran. Even with the 172 and the needle dropped it ran OK. The needle up though with the 172, it barely ran. Had about a 2K wide power band that started at 5k and ended at 7k.

A plug reading with the 160 and dropped needle still showed it as rich, so I'd take a few smaller pilots along. Drop it 2 full sizes as a good starting place, run the 160, drop the needle to the second slot, and you should be able to ride the booger. Oh, run the fuel screw 1.75 turns out and carry a tip to play with it with you.

This should remove any worries. Do the above and you'll be able to ride it no problem.

Mileage? The stock '00 tank is small, like 2.5 gallons. We did 60 one day miles but had to take about 1.2 gallons out of my XR. Still were not on reserve though when we got back to the van. This was with the 172 though, so I'd guess it was getting about 20 MPG that day. With a moderate throttle hand and the leaner jets I'd be planning around 22-23 mpg. My XR250 was getting about 40 in comparison.