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High Altitude Carb Adjustment

837 Views 16 Replies 7 Participants Last post by  Ridgway81432
I have two 04 & 06, 660's and live in North Alabama, I'm taking them to Colorado in July for 3 weeks of riding, has anyone had any luck with Thunder products "Dial a Jet" that leans/rich the carburetor? A lot of people change the jets to accommodate for altitude, we will be riding 6000 up to 12000 ft. Thank you in advance.
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For what it's worth I live in Colorado (alt 6500) and have ridden in the high country with my 2004 660. I changed the main from stock (#145) to a #140 main jet. I didn't have to make any other changes and she ran great. No matter how you tune it, it's gonna lose power at 10-13000ft. But I absolutely did not have any problem with it blubbering at altitude. With the same set-up I was able to do Moab Utah without any problem (although it was getting a little lean). Had I went any lower I would have changed back to the stock jetting. Will it run on stock jetting, sure it will just not sure how well. Mine ran like a raped ape without doing any air box drilling for altitude. My 2 cents.
As Ridgway mentioned we have ridden together a lot. His 660 is the meanest 660 I've ever seen. How much the holes in the lid vs what he's done with his CVT mods is anyone guess. But that thing flat rips and his bottom end off throttle has always amazed me. Mind you this is mainly at altitude, but when we rode at Moab it was still very impressive. I ran 5 psi in my Bighorns with no problem. I run 7psi in my Bighorns with the 14" rims on my 700. One of the reasons, I feel, that Ridgway runs 11 psi is the boy (I guess I can call him old now) is he hauls a$$ and likes to go through the gnarly stuff instead of around it. Either way, change jets or open-air box it will work. Hell, just leaving it alone may work as well. I've never heard anyone stating that they had to do anything to ride a 660 at altitude. I have never heard of anyone using a dial a jet so can't expound on it. So come out and enjoy riding the High Country with some beautiful scenery.
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These are the most popular - You can get 4-5 days of riding in the Ouray/Silverton area. Probably the most scenic. You'll have to trailer, or you can camp and ride out of camp. 1-2 moderate to hard trails. The next place is Taylor Park another 4-5 days of riding. More moderate trails and a couple of hard ones. they have a Trading Post there (Vacation Destination in Almont, CO (taylorparktradingpost.com) and has cabins (good luck trying to get one this late). They also have an RV park and camping sites. You can camp anywhere in the valley as well and ride to all the trail heads. I've ridden Taylor since 1986 and Ouray area since 2000. I'm old too, lol. If you ride here, you'll need a Colorado OHV sticker (like $25.25) and in some places (Ouray) you'll need insurance. Although I've never seen or heard of anyone getting stopped for an insurance card check.
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