Ever since I rejetted some 10-months ago, I've noticed the bike has an ever so slight surge/hesitation when running at a steady RPM/speed. It's very minor, most probably wouldn't even notice it. While riding it seems to be running fine, I see no change to my RPMs, speed or change in sound. But I can feel this ever so slight surge and hesitation when running at a constant speed. It's kinda like the carb might not be getting quite all the fuel it needs to maintain a constant RPM. It typically happens between 6,000 and 7,000 RPMs. Is this something that's inherent with single cylinder bikes and is this normal or is a little tweaking in order?

Clip on 3rd from top
128 main jet
About 2 3/4 turns out
Sea level

 

larger main?

 

Possibly low float?

 

I once had a similar symptom which turned out to be a little aluminum flake (possibly from the casting/milling process) stuck in the main jet.

 

No no no! Your bike got a really common symptom, and the fix have already been found. Have a look at this thread :

https://www.kawasakiforums.com/forum...e7/#post452954

It worked for my bike.
https://www.kawasakiforums.com/forum...e2/#post481202

 

Ya, I tried that ground wire mod just because it's so easy I had nothing to lose. The OP should probably give it a go too, but it didn't resolve the 6000rpm surge on my bike. I had to go inside the carb.

Good luck!

 

Thanks for the links D.C. I totally forgot about the rectifier ground. I'll do that tomorrow. I'm sure that's it.

 

Typically surging while at speeds means the main is a little undersized.

I opened up my air box before I did the rejet and I had the same symptoms. Once I rejetted the bike, and gave it a little more fuel, it smoothed out.

You might try the ground wire first just because it is easier, then i would go to the carb.

 

I have the same surge. Ground mod didn't fix it. Too lazy to open the carb. Someday I'll replace the tank, replace the valve cover gasket, de-smog, and rejet... someday. I like to just change oil, tires, and ride.

 

I hear you. I do add "lube chain/adjust if req'd"