Author Topic: Stuttering '97 B12 (Read 4586 times)

benp1981 · « **on:** August 15, 2007, 12:06:16 AM »

Hello folks-

This will be the first post of many as I just purchased a Bandit 1200. So far Ive been very pleased with it.... With the exception of a "stutter" at slow speeds. Between about 2k and 3k RPM when cruising through town, the bike will feel like its going on-off-on-off and bouncing tension against the cush drive.

It runs great once you bring the revs up past 3k.

I believe the bike has an Ivan stage one jet kit, holes in the airbox, and a vance and hines slip-on. Pilot screws are set to 3.5 turns.

Has anyone got any suggestions for making the bike smoother at slow speeds?

Thanks!

JamieK · « **Reply #1 on:** August 16, 2007, 12:15:59 AM »

Does Ivan's kit have needle clips? If so maybe raise the needles one stop to richen up the bottom end. If no clips then add a shim or two to raise the needles. That worked for mine when I was encountering a similar issue.

Pillage · « **Reply #2 on:** August 16, 2007, 09:33:21 AM »

Yup, one of the first things I did to my 97 B12 was to raise the needles with washers from radio shack. It's worked like a charm for many years.
Welcome to the site, these guys have helped me with many minor issues, that has helped me to set up my bike so it's perfect for me. I think you're going to like it here!

pmackie · « **Reply #3 on:** August 16, 2007, 12:52:55 PM »

You can try a couple of things:
1. Try adjusting the air screws "in" 1/2 turn. There is a chance you are too rich.
2. If it get worse, you may need to go to a larger pilot jet, as 3-1/2 turns out is about the limit. You could try 4 turns out just to see.
3. Raise the needles (drop the clip).
4. Sync the carbs.

okbandit · « **Reply #4 on:** August 16, 2007, 04:58:39 PM »

If the bike is bucking at small throttle inputs it is in the A/F screws. Play around and you will find the sweet spot. I am running an Ivan's on one of mine and IIRC mine is at 3 turns out if that helps. Too rich is usually a sluggish feel leaving a stop or maybe even a stumble. Too lean will surge. Too lean can cause the idle to hang and linger at higher revs for a short period of time and then return to the set rpm. Remember, this is only for small throttle inputs 1/4 turn and under (like cruising slow). Larger throttle inputs will be in the needles, say 1/4 to 3/4 throttle and usually cause symptoms at highway speeds.

benp1981 · « **Reply #5 on:** August 17, 2007, 12:22:23 AM »

Raised the needles one step and its running pretty good... Just the tiniest bit of stutter left.

Going to run it a little and see if I want to try raising the needles one more step... But its good for now.

Thanks for the warm welcome everyone

JamieK · « **Reply #6 on:** August 17, 2007, 12:45:18 AM »

No problem...happy to help

rider123 · « **Reply #7 on:** August 22, 2007, 12:50:27 PM »

Quote from: "pmackie"

You can try a couple of things:
1. Try adjusting the air screws "in" 1/2 turn. There is a chance you are too rich.
2. If it get worse, you may need to go to a larger pilot jet, as 3-1/2 turns out is about the limit. You could try 4 turns out just to see.
3. Raise the needles (drop the clip).
4. Sync the carbs.

I agree I had the same type of problem as I was too rich. I turned the mixture screws a 1/4 turn in and there was a big improvement in power and smoothness. Damn shops! Does the bike run better cold than hot? if so you're probably slightly rich on the screws. I have a holes shot kit and I'm 1/8th of a turn past 2 3/4. Just for fun try turning in the screws 1/4 turn and see if the throttle is crisper and smoother.