Hi I just rebuilt the motor on my quad and want to know where to start on the jetting. Here are the specs on the quad

bored 80 over
39mm carb
light port and polish
fmf pipe and silencer
fmf ram valve
barnett race clutch w/ billet basket

I started the jetting out at 170 but it was still lean, I have stepped it up and I am at 188 but it still seems lean. Anyone have any ideas for me. I have search this issue and it seems I should be at about 175, I have the air screw 1.5 turns out it that helps. Any help on this would be greatly appreciated. Thanks for the input.

 

check for air leaks...if u dont find any then just keep going up in big increments until it finally gets rich. You cant go by what other people have especially since you are ported. Dont pay attention to anything but your own.

 

When I was switching to my 35mm keihin, I got jetting specs from more than one person here with setups very similar to mine and they were all way off. 39mm is a pretty big carb and you're on your last bore, both of which are going to increase your fuel requirements. Read this.

 

i run a 185,if i remember right and like a 42 pilot. i use a 38mm carb. check my page for mods. i have it ported and rad valve etc. so try around there.

 

I agree with him 39 is to big unless you have alot of mods.

 

thanks for the info, took it up north today to go riding and tune it in better and found that 185 works best for me right now. It runs real strong until I hit a tree stump in the tight trails and broke a tie ride. haha. oh well. one more thing to fix. Thanks again for the suggestions.