5 second rule

sooo.... wondering if you guys could help me out... I am rebuilding a 1978 kz650 which hasnt been started due to neglect in about 5 years (bought it from an elderly man)and am switching parts with my previous daily rider... a 1978 kz650. After countless bloody knuckles, swearing at the bike, etc..... I got her running!..... for about 5 seconds. Since I have tried everything I can think of... messed with the air screws on the carb (which was switched over from my previous bike) checked this and that... but it will stubbornly start after a couple kick starts... struggle to 4000 rpms and then die immediately. so maybe something electrical? I cant think anymore so any advcice would be greatly appreciated.

Is it new gas?Have you cleaned the points?Checked for spark?Checked compression?Is a battery installed?

Does the gas flow out of the tank? If not try it with the gas cap open. If gas flows, disregard the first comment I made.

vaccume leak?

Timing? Sounds like it is possibly not firing on all four cylinders? My coils sometime after i touch any of the wiring like to mess up and it reluctantly starts but sounds almost like a harley and that is my clue to a misfire.

brianpclarke wrote:

...got her running!..... for about 5 seconds.... will stubbornly start after a couple kick starts... struggle to 4000 rpms and then die immediately....

Thinking possibly a fuel supply problem, but some fuel gradually making its way into the float bowl to allow running for a few seconds until the float bowl empties again.

With engine off, could experiment by opening float bowl drains and then turning on petcock and seeing whether fuel continously flows out the float bowl drain holes. If not, suspect low fuel in tank OR crud inside tank suspended around and clogging petcock filter inside tank OR petcock clogged OR petcock screen clogged OR fuel line clogged OR in-line fuel filter clogged OR fuel tank cap vent clogged.

Post edited by: Patton, at: 2007/11/12 11:10

Awesome! thanks for all the feedback! Tomorrow I am going to basically try all of these and nail it down or else I am going to go insane if I have to pull the jeep up to the gas station another time this week.... but what would a vacuum leak be? and how would i check this out?

The vacum leak would be anything to do with the rubber parts. Check fo cracks on the intake boots and make sure there are no open vacum fittings on top of the carbs.
Also try some light oil in the cylinders. If the bike has been sitting for a lonfg time the rings could be stuck. Roy

Post edited by: brianpclarke, at: 2007/11/13 17:57

oh.... sorry guys... the problem was a mixture between a weak spark and bad gas.... problem solved and my itch for Kawasaki riding gets worse....