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mslow

High Elevation Jetting Set-up Help

8 posts in this topic

Looking for some of you jetting guru's to help me get my wr sorted for a trip coming up.

Currently ride from 0' to 1000' elevation

Need jetting and total set-up advice for 8,000' - 14,000' max (Colorado Rockies)

Most of our riding will be in the 8k' - 10k' range

2005 WR450

Lexx Exhaust with spark arrestor and 34mm outlet

Stock header

No Toil air filter

All free mods done

Thanks in advance!

BTW, any other hints/tips for riding in the Rockie's would be great too!

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Roughly, you need 1% leaner jetting for each 1000' of altitude gain. If you shoot for a target range of say, 10,000 feet, then you'd need something about 9% leaner, assuming your current setup is perfect at 1000 feet. For example, a 165 main jet would become a 150, and a 45 pilot would go to 40.

But your current jetting probably works OK at up to 4000, so call it good for 2000 feet and go about 8% leaner.

Needle adjustment MAY be necessary, but as the needle meters fuel already metered by the main, you might not need to lower it.

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From experience I can tell you that my 165/48 w JD needle 3rd clip runs really well to 7,800ft in WA with the original tip and on my Lexx. I would put in a 155/42 and bring a few jets with you.

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Try 152 main, needle clip second from top, air screw 2 turns out, 12T front sprocket, and "engine ice" (or equivalent). Take lots of H2O to keep yourself hydrated.

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thanks fellas, i got the JD jet kit, adustable fuel screw and a few extra jets.

running 15/46 gearing with a rekluse z-start pro, it's been working awesome in the tight stuff, climbs and equally well on the road stints

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thanks fellas, i got the JD jet kit, adustable fuel screw and a few extra jets.

running 15/46 gearing with a rekluse z-start pro, it's been working awesome in the tight stuff, climbs and equally well on the road stints

Run 16/50 for longer chain/sprocket life. Make sure your engagement is set for extra hard extra low rpm to keep bike cooler

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152 on a warm day, 155 if it's cooler. That bike is not finicky, anything close will run.

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So i went with the JD jetting kit.

165 main

42 pilot

Red needle clip in 5th slot

Fuel screw 1 1/4 out

Since I'll be riding between 6k and 14k feet elevation, would it be smart to add an adjustable vent to the airbox to allow more flow in the higher elevations?

I was looking at the TPI adjustable vent with prefilter.

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