Turns over, won't start

Bike is 79 KZ650 SR with 16 K miles. Been stored for years. I cleaned and rebuild all four carbs. Bike turns over but doesn't fire up. Spark is present. What do you think?

You only need to post once . You say you cleaned the carbs, how is the fuel flow to the carbs? If you are using the stock vacuum petcock, make sure there is vacuum present on the vacuum hose going to it. As for your spark, is it a nice fat blue spark or a weak yellow spark? I would also check your compression, but I feel this is more of a fuel related problem.

crewzzn88 wrote:

Bike is 79 KZ650 SR with 16 K miles. Been stored for years. I cleaned and rebuild all four carbs. Bike turns over but doesn't fire up. Spark is present. What do you think?

my guess is your choke wells are plugged like 3 of mine were when i got my bike. take off the choke actuators and squirt some carb cleaner through them to see if theyre clear...if not start poking with some small wire till they are...good luck...steve

thanks, i'll try what you said. this is my first ever posting, so i wasn't sure if i did it right the first time.

steve, i checked the choke wells, seems clean. i might just send the whole thing to wiredgeorge.

Post edited by: crewzzn88, at: 2005/12/28 21:28

As someone else said here, you need air, fuel and a spark at the right time to get ignition. Since you say you have a spark, try spraying your air filters with starting fluid and trying, this is how I first got my 400 to start after decades of hibernation.

If this causes it to start, you're supplying extra fuel, so you probably have a carb problem.

George

Also needs compression.

To start, FIRST check to see if you have good compression on all cylinders. You need a gauge that is either threaded into the plug holes or press fit into them. Turn engine over with starter holding throttle wide open. If you have bad compression, try some Yamaha Ring Free right down the plug holes and let it sit for a day or so. This stuff often breaks loose stickey rings. If your rings are stuck, no amount of spark or gas will allow the bike to start.

Second, Pull the plugs one at a time and put the electrode near the engine and see if it sparks when you turn the engine over. Make sure the plug wires are in the right order. The plug wires from the right hand coil should go to 2/3 plugs and the left coil to 1/4 plugs. If you have spark, then:

Third, see if you have fuel... turn the fuel tap on and then open or remove the bowl drain screws. Do NOT assume they are full of gas. Check them. If you put a fuel filter inline, check to ensure it is oriented in the right direction. If you have a vacuum actuated petcock, put it on prime. This type petcock needs engine vacuum to flow gas and if the bike isn't running the bowls may not fill if the petcock is in the ON position. Plus these petcocks are notoriously flakey in their operation.

A small minor thought. A plug may spark in ambient air but if it is in a cylindar under copression it may not spark the same.

OK, I removed the cards again. I rechecked all my work. Found some dirt in 2 of 4 carbs. Ordered a rebuild kit for the accelerator pump. Now just waiting for parts to come in . I'll let you guys know if it starts or not. ps ordered stuff from Z1, hope it gets here soon.