04 viper Idle Hang

hessracing

hessracing

Member
Joined
Dec 10, 2009
Messages
315
Age
36
Location
Iron Mountain Michigan
Hey guys I dug into the viper this morning! I adjusted the power valves, the cables were really loose! And cleaned the carbs all 3 pilot jets were clogged shut, and the air screws were set at 1 3/4. I set the Air screws back to the factory 1 7/8 turns I took a zip around the yard and slowed down to turn and the TOR switch was acting up because I had the throttle cable to tight loosened it up that's fine. And now it seems to have a bit of an idle hang around 3000 rpms it only happens when your up to speed and then stop it hangs around 3000 rpms. The first thing i thought was well the idles to high so i cranked it down and it didn't change it immediately and if i hit the choke or give it a burp of gas it will idle down to the 1800 rpms and stay there. I did notice the guy had 3 holes drilled in the top of the air box right above the ports down to the carbs should I put some duct tape over those? its underneath the foam. Its something most people would live with and it wouldnt bother them but I want it to be right. machine is all stock stock exhaust.
 
did you raise the needles on this viper? if you didn't youll want to! run the fuel screws out to 2 turns and warm up the sled and set the idle speed to 1500rpm, that will eliminate the hang up. the holes drilled in box will lean it out.

midrange is where most all of the vipers burn down, you need to raise the needles even on a bone stock machine. with holes in airbox I would for sure raise them and make it richer, everytime you come down off high rpm you are into the needle circuit before you get into the pilot jet circuit for the idle.

the screws on the bottom are fuel screws not air screws, anytime you have the screw in front of the slide on the engine it controls fuel flow, if behind the slide it controls air. So the more they are turned out the richer it becomes within the adjustment wondow, after you get to 2 turns out you need a bigger pilot jet.
 
I never touched the needles what clip would you suggest putting them in? I can pull the carbs back off and turn the fuel screws out to 2 turns it looks like stock clip setting is 3? I'm not sure what they are at now
 
After you get the needles set up I would suggest changing the pilot jets, they are very difficult to clean because the holes are so small. I have cleaned them before with twisted thin strands of coper wire and carb cleaner, but carb cleaner and compressed air is usually not enough.

Sent from my SGH-I337M using Tapatalk
 
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