Sprockets

Pods.

ellwinger wrote:

Pods.

That could be your problem...

Nessism wrote:

ellwinger wrote:

Pods.

That could be your problem...

Definitely. APE, K&N and Uni filters will work just fine when the carbs are properly set up. Some of the cheaper filters actually block the air jets in the mouth of the carbs. Even the best filters will not take the place of properly done routine maintenance.

What year is the motorcycle? And is this a USA model or Canada/European? 
Does the motorcycle have the stock mufflers or aftermarket exhaust? 
What carburetors? VM24 or BS32.  Are the carburetor parts oem or aftermarket jetting stuff? 
Did you re-jet the carburetors or was it already done?
I would check the spark plugs to see if you're running lean. and make sure they're the correct plugs.
 

It's an 81 KZ650H USA. 4 into one exhaust. Aftermarket jets by me. Hot plug that looks clean when I check them. Are they the right ones? I dunno.  They came with the bike when I bought it for parts. The carbs have rectangular covers, not round (VM24?). In the meantime I was backing up my boat and knocked my garage over. The bike is in there somewhere 

This will help, but not with the garage. I hope everything inside survived.

www.kzrider.com/modules/ServiceManuals/K...l%20KZ650%201981.pdf

1981 KZ650-CSR came stock w VM24 carburetors w accelerator pump.   later models had BS32 cv carbs.
VM24s should work fine with good individual pod filters & proper jetting. use quality parts.
Carburetors, individual pod filters & exhaust system are considerations when figuring out the jetting.
Recommended/stock spark plugs are NGK B7ES (or ND W22ES-U). most guys go with the NGKs. make sure you aren't too lean. 
Pod filters + 4-1 exhaust & 107 main jets w unknown pilot jets could be lean. not sure. #17 pilots are typical w your air filter & exhaust setup, but I don't know that much about it.

edit:  check that the accelerator pump is functioning properly. see FSM for details.