New 1980 KZ650 carb ???'s

Hi all this is my first post. I just recently bought a 1980 KZ650 for my birthday, it runs & rides but definitely needs a good tuneup. The bike has no issues starting right up, it's idle is okay but it intermittently spits what looks to be air out of the side of the carbs. It does not only do this while the bike is idling or only when it is cold, it will do this even when the bike is warmed up. Anyone know what this could be?? It also smells like it could be running rich, how do I tune the carbs?? I believe the carbs are stock, and it has about 18K on the motor. Also any other things to check or tune up on the bike?

Thank you all for any help!!

Step one. Edit your profile signature and add your name, bike year/model and your location.

Step two. Buy a Kaw factory service manual or Clymers manual and read the fuel section.

OK... as to the spitting, this is caused by incomplete combustion. It may be due to the wrong fuel mixture caused by the carburetors being in need of thorough cleaning or it may from other reasons such as ignition timing or poor spark. Poor spark is often caused by poor voltage at the coils and the coils not firing as much voltage as they should. We have a tech article on this issue on our website... see my sig and look under wg' TECH STUFF INDEX for the Coil Repowering write up.

If I owned your bike, I would start with a FULL tune up as described in the manual, then do the coil repowering, if it makes sense to you before mucking with the carburetors which are more or less, the LAST step in the tune up process. When you get to them, you will first adjust the idle mixture, set the idle and then synchronize. If doing this stuff in the order described doesn't fix the backfiring, the carburetors most likely need cleaning/rebuilding.

Okay so step 1 and 2 are done... A Clymer manual came with the bike!

So I have not read throuroughly in the manual but I take it that how to adjust fuel mixture and how to sync the carbs is all in the manual.

One other thing where is a good place to buy parts for these bikes? I need to get the stock headlamp assembly and the basic parts needed for the tuneup.

Post edited by: jolio55, at: 2008/03/04 09:51

jolio55 wrote:

... where is a good place to buy parts for these bikes?....

Here's a good starting place --

Z1E