air fuel mixture screw
Thread Starter
|
Advanced
Joined: Apr 2006
Posts: 63
Likes: 0
From: Hollidaysburg, PA
air fuel mixture screw
Has anyone tryed ajusting it without a rejet? I just installed v&h short shots and still have stock ac. I read a post yesterday about jetting and it said to drill the cap out and try tuning it like this before jetting. Is this a good idea, or should i wait till i get a ac and jet it?
Stellar HDF Member
Joined: Nov 2005
Posts: 2,272
Likes: 10
From: Orange VA
RE: air fuel mixture screw
The short answer is yes you can try adjusting the idle mixture screw alone, separate from a rejet.
Changing the exhaust without the AC or rejet does not require rejetting or adjusting idle mixture (in most cases). Ride around with your new pipes and see if you encounter any drivability issues first. Give it 10-50 miles under normal driving conditions to realistically assess it. If none, don’t worry about rejetting or adjusting anything right now.
If you do want to play with the mixture now… Note the general rule is that if you come out more than 3.5 turns from bottomed-out, you need to jump to the next jet; need a rejet or jet kit. Assume it already has a few turns from the factory so you may or may not have a lot of adjustment room left.
Make sure you know where the screw was when you started. If you mess up or decide it was ok at the stock setting you can go back to it easily. To do this, I suggest marking your screw driver with a marker or something to note the starting position. Turn the screw all the way in until it stops, taking note of how many turns it took to get there (2, 2.25, 2.5…or similar). This is an important step. This will tell you how much adjustment room you have. Example: You find the bike was tuned at 2.5 turns out. If 3.5 turns is max then 3.5 – 2.5 = 1 turn of adjustment available.
Once you know where it was set stock you have three choices, go back to stock and do guess-timating adjustments, follow the steps to properly adjust the carb from scratch, or put it back where it was and do nothing. For both adjustment choices, refer to proper carb adjustment – A/F ratio to ensure proper tuning.
But like I mentioned, if you only changed the exhaust, it’s likely you won’t need to adjust anything. In contrast however, if you do change the AC, you will need to adjust the carb and it is likely you will not be able to do so effectively without changing jets.
Changing the exhaust without the AC or rejet does not require rejetting or adjusting idle mixture (in most cases). Ride around with your new pipes and see if you encounter any drivability issues first. Give it 10-50 miles under normal driving conditions to realistically assess it. If none, don’t worry about rejetting or adjusting anything right now.
If you do want to play with the mixture now… Note the general rule is that if you come out more than 3.5 turns from bottomed-out, you need to jump to the next jet; need a rejet or jet kit. Assume it already has a few turns from the factory so you may or may not have a lot of adjustment room left.
Make sure you know where the screw was when you started. If you mess up or decide it was ok at the stock setting you can go back to it easily. To do this, I suggest marking your screw driver with a marker or something to note the starting position. Turn the screw all the way in until it stops, taking note of how many turns it took to get there (2, 2.25, 2.5…or similar). This is an important step. This will tell you how much adjustment room you have. Example: You find the bike was tuned at 2.5 turns out. If 3.5 turns is max then 3.5 – 2.5 = 1 turn of adjustment available.
Once you know where it was set stock you have three choices, go back to stock and do guess-timating adjustments, follow the steps to properly adjust the carb from scratch, or put it back where it was and do nothing. For both adjustment choices, refer to proper carb adjustment – A/F ratio to ensure proper tuning.
But like I mentioned, if you only changed the exhaust, it’s likely you won’t need to adjust anything. In contrast however, if you do change the AC, you will need to adjust the carb and it is likely you will not be able to do so effectively without changing jets.
Road Master
Joined: Nov 2006
Posts: 861
Likes: 0
From: Grosse Ile, Mi
RE: air fuel mixture screw
Of course it's a good idea. In some instances, it may even do the trick. Chances are it won't but, you will get a feel for how to do it. Remember, turning the idle (right/rich) out makes for a richer adjustment, turning in makes (left/lean) it leaner. Set your idle speed on the low side so that you can feel and hear the subtle changes of the motor as you turn the idle mixture screw. Generally, 2 turns out is the right place to be.
Thread Starter
|
Advanced
Joined: Apr 2006
Posts: 63
Likes: 0
From: Hollidaysburg, PA
RE: air fuel mixture screw
Thanks alot, I know it is running a good bit lean I think I will just go pick up some jets and a air cleaner from the dealer tomorrow and get it over with.
Novice
Joined: Feb 2007
Posts: 17
Likes: 0
From:
RE: air fuel mixture screw
I just bought my bike used and the guy didnt know if they had rejetted it when he put Screamin Eagle pipes on it. So today I pulled the carb off to find out and it has been rejetted (45-165) K + N air filter. The air screw still had the little cover over it so I pulled it off and the air screw was turned all the way in [
]. This cant be right is it? With the cover on tells me the dealer never messed with it or am I crazy.
I am sure it would not turn IN any more but turned out 2 turns easily. I cant ride it because of the weather and pulled of the stuff to put on the bigger front pulley.
What do you think? Could the dealer have done that and put the little cap back on?
Or are they turned all the way in stock? doesnt seem possible.
]. This cant be right is it? With the cover on tells me the dealer never messed with it or am I crazy. I am sure it would not turn IN any more but turned out 2 turns easily. I cant ride it because of the weather and pulled of the stuff to put on the bigger front pulley.
What do you think? Could the dealer have done that and put the little cap back on?
Or are they turned all the way in stock? doesnt seem possible.
Stellar HDF Member
Joined: Nov 2005
Posts: 2,272
Likes: 10
From: Orange VA
RE: air fuel mixture screw
I've never heard of anyone putting the plug back into the carb but that does not mean they didn't do it. Another theory is that someone changed jets but never touched the idle mixture. That would be odd, especially for a dealer service install but I suppose its possible.
It does seem they rejetted. For 04-06 883's stock jets are 42/175 (49 state) or 42/180 (CA). 04-06 1200's stock jets are 42/180 (49 state) or 42/185 (CA).
Every setup has its uniqueness but having the mixture screw all the way in doesn't sound like a common setting. Having said that, I'd consider how it rides to be a better evaluation than comparing your settings to everyone else's. I'd only worry about it if you find its not performing properly.
It does seem they rejetted. For 04-06 883's stock jets are 42/175 (49 state) or 42/180 (CA). 04-06 1200's stock jets are 42/180 (49 state) or 42/185 (CA).
Every setup has its uniqueness but having the mixture screw all the way in doesn't sound like a common setting. Having said that, I'd consider how it rides to be a better evaluation than comparing your settings to everyone else's. I'd only worry about it if you find its not performing properly.
Trending Topics
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
RE: air fuel mixture screw
bensonjv, I thought Calf required a leaner mixture than other states for emissions. Your numbers indicate a larger main jet for Calf. or am I confused?
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
6 Weirdest Harley-Davidsons Ever Sold to the Public
Verdad Gallardo
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
Road Warrior
Joined: Jul 2006
Posts: 1,351
Likes: 4
From:
RE: air fuel mixture screw
I believe that the cap/plug was put in after the emissions test is done at the factory. Each engine being slightly different would mean that it could have been set that way from the get-go.
Not knowing the factory destination for your bike or a history from your dealer makes it a bit foggy to answer this question completely.
Also, I doubt it was replugged. Dealers don't usually have those brass plugs just laying around. They have to be drilled to take them out...thus is yours was not drilled..I doubt it was ever out other than at the factory. Jus my 2 cents there.
Not knowing the factory destination for your bike or a history from your dealer makes it a bit foggy to answer this question completely.
Also, I doubt it was replugged. Dealers don't usually have those brass plugs just laying around. They have to be drilled to take them out...thus is yours was not drilled..I doubt it was ever out other than at the factory. Jus my 2 cents there.
Thread
Thread Starter
Forum
Replies
Last Post
