Low Speed Surging

[PHATASS]

Bike surges/jerks at low speeds when thottle is barely opened. Any ideas?

2007 K9
80 Main
33 Intermediate
S&S Twin Induction Intake
XXX G Carb w/ Booster Kit
Stainless Creations Chaos II Exhaust

 

[steve03mastiff]

my mastiff was doing that also. i adjusted the accelerator pump screw in 1/4 turn at a time, it finally stopped the surging and is running great.
hope the link below helps. it did for me. i also went to an 82 main jet, but running a 31 interm. jet. but, my mastiff is a 107.

Super E & G CARBURETOR TUNING GUIDE

 

[HotRod]

What rpm are you running? You might be lugging the motor.

 

[PHATASS]

my mastiff was doing that also. i adjusted the accelerator pump screw in 1/4 turn at a time, it finally stopped the surging and is running great.
hope the link below helps. it did for me. i also went to an 82 main jet, but running a 31 interm. jet. but, my mastiff is a 107.

Super E & G CARBURETOR TUNING GUIDE

Thanks Steve, I'll try that tomorrow.

 

[PHATASS]

What rpm are you running? You might be lugging the motor.

Only about 1200-1400 rpm in 1st. It happens on the initial take-off with the throttle slightly opened.

 

[Olde Man]

I had the same problem. It was kind of scary going around a corner without having the clutch pulled in. It acted like 0 to 30% throttle instantaneously. I called S&S they said it was to fat on the intermediate and to go down one size. They were absolutely right. Problem solved.

 

[Ray]

I saw this and what I have to say might not help this issue , but I had been running 93 octane gas I knew had ethanol in it. My scooter would spudder and spit a little from time to time. I quit running ethanol gas and that seemed to solve that issue.

Ray

 

[what?]

Did you do any mods to the exhaust?

I recently removed the baffles from the stock exhaust on my 08 pit. In first and second the bike runs like its engine braking then when you hit the gas it surges. Once up to speed and in higher gears it does not seem to happen. Prior to modifying the exhaust and admittedly messing with the carb adjustments this did not happen. It was much smoother when the baffles were in. Maybe a compression issue:loony:.

 

[PHATASS]

I had the same problem. It was kind of scary going around a corner without having the clutch pulled in. It acted like 0 to 30% throttle instantaneously. I called S&S they said it was to fat on the intermediate and to go down one size. They were absolutely right. Problem solved.

No mods to the exhaust. I'll be digging into the carb tomorrow to make sure all jets are clean. I have popping on decel too so may have to mess with the intermediate while in there.

 

[PHATASS]

I had the same problem. It was kind of scary going around a corner without having the clutch pulled in. It acted like 0 to 30% throttle instantaneously. I called S&S they said it was to fat on the intermediate and to go down one size. They were absolutely right. Problem solved.

What set-up were you running when you had the problem?

 

[Olde Man]

I was running 32 now 31 and it cleared up.

 

[MARV]

Only about 1200-1400 rpm in 1st. It happens on the initial take-off with the throttle slightly opened.

sign of a lean condition

 

[lee]

what cam do you have? A torquey cam needs higher air velocity to run well and that can cause this. I doubt its your problem but I thought I'd throw that out there.

 

[PHATASS]

what cam do you have? A torquey cam needs higher air velocity to run well and that can cause this. I doubt its your problem but I thought I'd throw that out there.

Stock cam

 

[Thumper]

Watch for an intake leak