I have 2 completely stock machines. KFX 700 and a Recon. I recently moved to an elevation of 6000-7000 feet. I called a dealer and they said to go up 2 sizes on the main jets but the local dealer told me he has had no problems with the stock jetting because the carbs are operated with vacume. Which one is correct and if so, what size jets should I run in each. Thanks.

 

MacV, A few of us live just down the hill from you in Running Springs. You're going to find that most of your sport riding will probably be at lower elevations. The fire roads up here are somwhat boring after a few miles, but Johnson Valley, Rasor Road, Ocotillo Wells, and Glamis aren't that far away. For that reason, I'm leaving my jetting alone. I would rather run rich up here than run too lean down in the desert.

As far as jetting, I wouldn't go UP in size, but down. You'll probably want to lower your jet needle as well.

There are several technical trails up here where the Recon would really shine. Give me a PM sometime if you would like to ride. I'm in Big Bear almost daily.

-----Paul

 

In another post, I suggested the TPI valves (http://www.thunderproducts.com/tpi_valve.htm). I have them on my Ranchers (installed in the airbox lid), which are the ones I ride in the mountains. The system works very well for me!

I live in the valley, and my bikes are jetted for sea level. As I ascend into the mountains, I gradually open the valves to give a greater volume of air, thus compensating for the less dense air found at high altitude. (Above 10,000', I just pull the airbox lid off altogether.) This gives a "balanced" compensation, that effects all the 4 different fuel circuits in the carburator, unlike just changing out the main jet which is what most people do.

The Thunder Dial-A-Jet, looks interesting also! (http://www.thunderproducts.com/dial_a_jet.htm).

MacV-Just a note: On the Recon, there isn't enough room in the lid to install the TPI. It sticks in to low, and hits the air filter. On that machine (and the 250EX), I use the 1" round UNI filtered air vents (http://www.unifilter.com/accessory-catalog.htm). I have 6 of them in the lid, and I do the old duct tape thing with them (remove tape as I ascend and replace as I descend), like we did in the old days.