New engine not running well

[David Line]

after installing my new engine, it does not run well at all. It seems to only be firing on one cylinder, but the cylinder that fires seems to vary. It is as if both carbs wont work at the same time. one seems to be working and the other is dry, and then it switches. this is a '95 Kawi 750 with Kehin carbs.

Thanks.

[Bryan Glynn]

How did the original fail, how long did it sit between egnines, and did you rebuild the carbs? How was it working on the old engine?

[David Line]

Thank You for your quick response.

The old engine ran great, right up to the point that it threw the piston. I ordered the new engine 2 days later,so it has not sat more than a week. I did take the carbs apart and clean them, I did not have a rebuild kit cause your out of them, but everything looked good inside. the o rings stil had good shape, and the needles are fine. The diaphrams look a little stretched, but again it was workin fine until I blew the engine. I am using the old plugs because of the carb adjustment instructions, maybe I'll try the newer ones tomorrow.

Thanks again,

[Bryan Glynn]

First of all, you NEED to rebuild the carbs - you cannot open them and reuse the gaskets and diaphrams.

Second, try the new plugs - but I bet the carbs needing a rebuild is 100% of the problem.