Surge

[Ped]

Hi Les,

No, it's not common to these bikes. They usually run clean regardless of 
RPM. But they also run lean from factory so it doesn't take much to 
disturb the smooth running of this wonderful engine.

Mine can surge under certain conditions: If the carb vent hoses are not 
placed where they should be (behind the air box), riding in windy or 
turbulent wind conditions - particularly in crosswind conditions - may 
cause the engine to surge the way you describe. If you open the throttle 
the pull all the way up will be clean. If you think the surge is 
somewhat related to wind conditions I would recommend you look first at 
the carb vent hoses and also check that the intake to the air box is 
undisturbed. I think there is a good chance that your problem is related 
to the vent hoses and that the fix is simple and effective.

I had exactly the same problem with the Suzuki GSX 750 ES I had before. 
This however was in any wind condition, also in smooth air and it was 
driving me crazy. I was almost on the edge of selling the bike when some 
day I noticed that when I sat in the seat a gap would open between the 
front end of the seat and the rear end of the tank - right on top of the 
intake. On the next ride I tried to hold my hand over this gap - and the 
surging was gone! Lesson learned: No turbulent air allowed in the intake 
area. You could try to isolate potential troubled air by filling cloth 
in gaps or taping them over.

Do you have stock exhaust? After market exhausts can do strange things 
to engine characteristics. If your exhaust is other than stock I won't 
start guessing on what might be wrong. It could be a million things.

Ped
'96 "Black Stealth" GPZ
Denmark

Dad (Les) Johnson skrev:
>        I purchased a used  96 GPZ 1100. I am currently working on getting it
> serviced and running strong to my liking.The bike seems to surge (noticed
> more in lower gears) when you try to cruise it at a steady RPM between 1000
> to 3500 .  After that it runs fine on up to red line.. It has done this ever
> since I first test drove it. The plugs look close to new but showed just a
> very slight hint of light tan on a couple of them. The others are white on
> the porcelain . Looks to me it's running lean. I am at about 200 ft elev. I
> can put the chock on with it running and it seems to run better in those RPM
> ranges.  I know I had a ZX-11D that had a flat spot in the power band. I
> ended up shimming the needles and cured that. The problem was different from
> this. This seems to happen with the throttle just barely open. I am
> wondering if this is common to this bikes? Maybe the pilot jet screws need
> screwed out another 1/2 turn or so. I also drained some  gas from two of the
> float bowls to see the condition. There was just a very ,very  slight hint
> of super small particles. I wouldn't think enough to clog anything. Any
> thoughts on proceeding from here?
>
>