Carb Question

Chics LI · #1 (**permalink**) 05-05-2003, 08:53 AM

I have a Road Demon 650 on a 351 with Edelbock Air Gap intake.
Here is the problem, after a sudden stop, as when I was checking out my new brake pads I have an idle surge up maybe 800 RPM and then idle will go back to normal around 5 to 10 seconds later or if I blip the gas pedal.
THIS SEEMS TO HAPPEN CONSISTANTLY BUT ONLY ON"PANIC TYPE STOPS" situations.
I thought maybe float level is screwed up, but wouldn't the car stall intead of surging upward ? Anyone have any advise, only other problem is running a little rich and hard starting, choke works but comes off too fast so you have to feather it awhile till it warms up a bit or it will stall until it is fully warmed up.

Tom S.

Mr.Fixit · #2 (**permalink**) 05-05-2003, 09:05 AM

So during panic braking, the idle goes UP?
If the motor's idle drops during hard braking, it isusually the rear fuel bolw overfolwing through the vent tuba and making the motor go too rich and almost stall.
If your's is going up, you might have the idle adjustement too rich, during braking the fuel sloshes away from the pickups for the idle circuit and leans out a little.

Or there is something really odd going on and the throttle is opening somehow during braking? Such as when you accidently depress both the brake and gas pedals.

Excaliber · #3 (**permalink**) 05-05-2003, 09:31 AM

Power brake unit? Hard quick braking using up all the "stored" vacuum and affecting the engine idle while it builds it back?

Ernie

Chics LI · #4 (**permalink**) 05-05-2003, 10:08 AM

No power brakes and I am not hitting gas and brake pedals at the same time guys. Really weird I know but it seems to happen every time I get on brakes hard. Kick in cluth hit brakes, finally stop and idle just goes up.

Tom S.

Chics LI · #5 (**permalink**) 05-05-2003, 10:16 AM

This all came about when I changed my pads bedded them in and tried adjusting my proportioning valve and ended up with fast idle when trying to lock up brakes. Changed out my calipers tried different pads because I wasn't happy with brakes, went through bedding new pads and testing brakes all over.. Everytime I locked it up my idle went up....would run steady at higher rpm and then settle back to normal idle by itself or if I blipped pedal.

Tom S.

Mr.Fixit · #6 (**permalink**) 05-05-2003, 03:22 PM

Try adjusting you idle mixture settings then. It is finding a better idle mixture under odd circumstances, when fuel is either being denied or supplied in excess due to fuel bowl sloshing.