KZ750 CV34 wants to rev to 4.5k?

With the OEM boots, you don't need any sort of crappy aftermarket goop to make them seal.  Use a little silicone grease, or nothing at all, when installing them.  

P1030216 by nessism , on Flickr

The new carb boots are on, they definitely look much better than the chinease ones that were $20. Much bigger O ring, and overall better quality. Unfortunately that did not fix my air leak. Carb cleaner has allowed me to narrow it down to the petcock area. Since my petcock is vacuum actuated it may be a loose connection because the actual line holds a sustained vacuum. I purchased a 1/4” fuel line but have yet to put it on there. If that does not work and the RPM still reacts to carb cleaner around the petcock, I will run it on prime and close off the carb with a vacuum cap and see if that changes anything. I realize it wouldn’t be good for a sustained amount of time but long e going to tell me if that is the issue. Any tips or recommendations?

Perhaps the diaphragm in the petcock is shot.

Texas luckily it wasn’t, just a bad connection on the vacuum line. New 1/4” fuel line and hose clamps and she’s back to running properly now. 

wrote:

Texas luckily it wasn’t, just a bad connection on the vacuum line. New 1/4” fuel line and hose clamps and she’s back to running properly now. 

The factory fuel and vacuum line is not imperial dimension materials.  It's metric.  And it's totally different from the common US type fuel line, which is thick and has a fabric braid inside to resist high pressure. The Japanese stuff is thin and stretchy.  Designed for motorcycles without a fuel pump.  Get some OEM fuel line, and you don't need a clamp.  I recommend Suzuki GS fuel line.  It's 7mm and stretchy, and they give you about 5' of the stuff.  Enough for several bikes.  

wrote:

wrote:

Texas luckily it wasn’t, just a bad connection on the vacuum line. New 1/4” fuel line and hose clamps and she’s back to running properly now. 

The factory fuel and vacuum line is not imperial dimension materials.  It's metric.  And it's totally different from the common US type fuel line, which is thick and has a fabric braid inside to resist high pressure. The Japanese stuff is thin and stretchy.  Designed for motorcycles without a fuel pump.  Get some OEM fuel line, and you don't need a clamp.  I recommend Suzuki GS fuel line.  It's 7mm and stretchy, and they give you about 5' of the stuff.  Enough for several bikes.  

This.