DR650 jetting Q's

[bullittman281]

Hello,

I'm trying to get my new to me dr 650 dialed in. I ride at 6500 feet and above. The thing is bone stock and for the most part its gonna the stay that way. However, I've hit a snag on its jetting. Currently it has the stock 42.5 pilot and the 140 main. I can't figure out if I'm lean or rich on the Main jet. The only thing not stock is I've pulled the snorkel. My problem is when I roll off of the throttle. When I roll the throttle on I have no problems and when I keep the throttle steady I don't have any problems but when I chop the throttle there is a nasty bog. At less than wide open the problem is less pronounced but not gone. I think I'm way rich on the main but I don't know. If somebody knows which way to go to kill the bog or what the hot set up for a high altitude stock bike let me know. Thanks.

Bullittman

[ProCycle]

On an 'all stock' bike the original 140 main is too big. I estimate a 135 should be closer to correct.

[donwann]

Go with an after market exhaust. I found that mine ran better after installing an exhuast without any airbox mods. I'm at a GPS measure 3600ft.

[ned37d]

pull your carb bowl and remove the pilot jet. run a single strand of about a #16 wire thru it and follow that up with some spray.

[mxrob]

+1 The stock 140 is rich at sea level even with the snorkel removed. If you load your engine and then quickly back off and it stumbles you are certainly rich. Considering your elevation I'd go to a 135 or even leaner....

[ned37d]

my bike is run at elevations from 3500 to 7500 feet. i have the airbox cut, gsxr muffler and dynajet kit using a 155 mainjet. runs fine.

i have experienced the same problems with deceleration sputtering, caused by plugged pilot. they get plugged easy due to the small hole. they also get smaller if you let the fuel evaporate from the carb causing a film to stick to it. the wire cleans that out if its there. only use copper wire, not steel.

[mxrob]

my bike is run at elevations from 3500 to 7500 feet. i have the airbox cut, gsxr muffler and dynajet kit using a 155 mainjet. runs fine.

i have experienced the same problems with deceleration sputtering, caused by plugged pilot. they get plugged easy due to the small hole. they also get smaller if you let the fuel evaporate from the carb causing a film to stick to it. the wire cleans that out if its there. only use copper wire, not steel.

Yep, yours is a complete different animal from a bike with a stock air box... ?

[bullittman281]

hello,

Thanks for the posts guys, but remember, stock. The bike is stock at high altitude. I'm gonna give the 135 main a try. The carb is squeaky clean. I just cleaned it all really good. If somebody has the ultimate stock bike high altitude jetting, hook me up. Keep the posts coming. Thanks guys.

Bullittman

[bullittman281]

Hello,

Just an up date. The bike is way better with the 135 but it seems it could maybe use a bit smaller. Is a 130 too small? I'm at 6,000 feet and above for what its worth. Let me know.

Bullittman

[ProCycle]

Hello,

Just an up date. The bike is way better with the 135 but it seems it could maybe use a bit smaller. Is a 130 too small? I'm at 6,000 feet and above for what its worth. Let me know.

Bullittman

A 130 is probably fine. You could have trouble if you ever ventured down to low elevations.

[mxrob]

Hello,

Just an up date. The bike is way better with the 135 but it seems it could maybe use a bit smaller. Is a 130 too small? I'm at 6,000 feet and above for what its worth. Let me know.

Bullittman

Try snatching the snorkel out and see if it improves any over the 135. It will help with mid-range as well. Just a bit more noise.... if you don't like it you can always put it back in and jet leaner but you will lose some of the mid-range.