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View Full Version : slow air screw on a 39 fcr ?



HOT-ROD
01-01-2003, 06:30 PM
how do you know how to check if this screw is adjusted properly ?

stupid driver
01-01-2003, 08:26 PM
when you hit the throttle and it stumbles you need to screw it out 1/4 turn at a time till it stops. this is not counting when your in neutral and you hit it, because it will always do that. it takes a split second for the fuel to catch up to the big breath of air your quads takin when you nail the throttle when your in neutral, and that will cause a small stumble

HOT-ROD
01-03-2003, 12:49 PM
Originally posted by stupid driver
when you hit the throttle and it stumbles you need to screw it out 1/4 turn at a time till it stops. this is not counting when your in neutral and you hit it, because it will always do that. it takes a split second for the fuel to catch up to the big breath of air your quads takin when you nail the throttle when your in neutral, and that will cause a small stumble what size main jet are you running ? i'm running a 170 main and a 52 pilot . does that sound right for below 3000 feet ?

lilpoppy
01-03-2003, 06:16 PM
Where do you guys get the pilot jets from for the FCR 39?

stupid driver
01-03-2003, 10:44 PM
im running a 165 main and a 50 or 52 pilot, but all i got is the pipe/filter and carb so 170 sounds about right

lilpoppy
01-14-2003, 10:44 PM
When you guys say air screw are you referring to the screw on the bottom of the carb or the pilot screw inside of the carb.

oregonrider89
01-15-2003, 10:10 AM
lilpoppy,

I had to get my pilot jets at a local Harley shop. The local bike shop didn't carry the style of pilots I needed. The best way to do it is take in your old pilot jet and make sure the new one matches it.

oregonrider89

Colby@C&DRacing
01-15-2003, 11:09 AM
Both the fuel screw on the bottom of the carb and the air screw in the back of the carb under the air boot adaptor need to be turned out 2 or 2 1/4 turns out. A 52 pilot works very well. I stock those jets. If anyone has any tuning questions let me know I have worked with them alot.

Colby at C&D Racing
308-696-7805

lilpoppy
01-16-2003, 12:43 AM
i can deffinatly use some help with this carb. It came with 165 main and 52 pilot. I have it running pretty good now and when i check the plug it is a good shade of brown. Basically the only problem I'm having now is that when I go wide open throttle from a stand still it boggs down so hard that it wont accelerate at all and if I hold it it will die. If I'm at a stand still and i give it a few revs before i go wide open throttle then it seems to be fine. Is this normal or do I need to adjust something? Now when you say there are 2 screws that need to be about 2 1/2 screws out you are refering to the pilot which is right in front of the main jet and the screw that is accessable even with the bowl still attached right? Thanks for your help.