V-Twin Forum banner
1 - 2 of 2 Posts

Retired Bubblehead
202 Posts
Discussion Starter · #1 ·
Ok, jump to the end for the question, read on if you want the background!^rolleyez^

So I've read numerous threads here on how to setup a carb, and I acknowledge up front the value of using a dyno, however for now I'm looking for "ballpark" advice on how to setup my carb.

I bought my '04 Fatboy last August and it came with V&H Straight Shot pipes (VERY loud!) and SE air filter. Otherwise, the drive train is stock. The bike seemed to run "OK" to me, but a friend's 95" kit fatboy seemed like night and day compared to mine. As the temps began to drop here in CT, the bike ran rougher. In the summer it would occasionally "spit" back out the carb, but this became much worse with the cold weather.

In November, I decided to have the local HD dealership service the bike including installing a dynajet kit and setting up the carb properly since I didn't think it had ever been right since pipes/AC done by previous owner.

Got the bike back and road it twice before putting it away for the winter and it definitely pulled harder at low RPM and no more spitting.

Well, as I said before, those straight shot pipes were just too loud for me, especially if I want to keep peace with my neighbors at 5am! So, I picked up a 2-1 V&H Pro Pipe on E-bay for cheap, looking for less noise and better performance.

Yesterday, I installed the pipe and took the bike for a short spin just to get it up to normal operating temps. The roads were too sandy for me to do much with the bike so I'm not sure how well it was running, that will have to wait for springtime. :(

So after all that, heres my question. Should I need to change the carb much after switching from the V&H Straight Shots to the V&H Pro Pipe? My carb is currently setup as follows for the Straight Shots and SE AC:

Mixture screw 3 turns out
Clip on 4th slot
45 slow jet
180 main jet

Will I need larger main jet, extra 1/2 turn or so on the mix screw?

Suggestions are appreciate and thanks in advance!

Vince (anxious for the warm weather)

2,092 Posts
Leave main alone. 180 is good reference
If in doubt, run on open highway wide open. A few times, you'll know.
Run bike till hot, turn screw fukll lean, adjust A/F till 1/2 turn above idle hanging up (rev @ idle, rpms return to idle without hanging up)
It's all up to needle height now. Adjust as necessary.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.