Using a DynoJet kit: I drilled the slide vent, 128 main jet, #4 slot from top on the needle. (I also went with the 13t sprocket, 3/8" crank case vent hole, and drilled exhaust 1/2")

During the test ride I noticed the bike was a bit blubbery and the plug was black when I pulled it. After switching to #3 from top on the needle, the plug looks brown. My area of Idaho is at 2367 ft and I ride up to around 6500 ft. Hope this helps.

 

Jeff,

Being at a whopping 75 feet above sea level - actually lower than on the deck of a nuclear aircraft carrier - I don't have much experience with altitude.

However, I would suggest switching to the 125 jet for starters.

 

Thanks Marty, but changing the clip to the #3 spot on the needle sorted it all out for me. The plug is just the right color of brown. No surging, blubbering, pinging, popping, or backfiring. It is in the sweetspot (for my elevation) now and I was posting the info for those who are tweaking their carbs at or around my elevation.

 

Well, I need to revise my earlier statement. Marty was right. I was testing my bike in the valley. As soon as I gained some elevation on a serious test ride I was back to blubbering. I rejetted to 124 main, stayed at #3 on the clip and went with 2 turns on the mixture screw. We will see... Sorry Marty, I bow to superior knowledge.

 

Ok! The previously mentioned setup worked great on a ride that took me from 2700 ft up to somewhere around 4500 ft. The bike was great and I noticed that it was making more power. Excellent call, Marty.