81 KZ 650 won't start without stater fluid

Hi All.... new to the board but loving all the great info. I just bought an 81 kz650 with 8 K original miles and got it running after sitting in a shed for a year. The guy I bought it from said that about 3 months ago he was going to revive the old bike so he rebuilt the carbs.

I can get the bike to crank by adding a quick spray of starter fluid to the filter intake under the seat. It will spin over 2-3 times and crank fine. After warming up it will throttle up and down fine. I can then kill it and it will crank again without starter fluid.

If I wait 15-20 minutes and allow it to cool it won't crank on its own. It will just spin and spin. I will add full choke and still it will just spin. One short squirt of starter fluid and vroom it is cranked.

Any ideas on what is going on? It seems like the engine isn't getting gas in the cylinders from just spinning the engine. But once it cranks from start fluid it has enough suction to pull gas into cylinders. Absolutely no smoke out the pipes... so cylinder wear shouldn't be an issue. Any ideas????

Maybe dirty jets??/

when he rebuilt the carbs, maybe he didn't hook up the choke? and the starter fluid is serving as the choke?

No... Once it cranks from the single squirt of starter fluid you can engage the choke and it revs up like it should. So the choke is working.

If i were you i would take the carbs off and check them out. He may may have missed something...How about the gas is it fresh?

I figured it out guys. The tank was off the bike when I got it. I has used a funnel connect to a piece of fuel line to get fuel to the carbs. I didn't realize that vacuume line coming from the carb was suppossed to be plugged into the petcock. I had left the vaccume line open. I plugged the line with a screw and it now starts without the starter fluid.

Yippie... Thanks for the help....