In the garage - posting via my phone - and my zx9 engine is running on 3 cylinders. We have stripped and cleaned and checked the carb on cylinder 1 but it will only run if i almost completely cover the inlet therefore starving it of air. Then it fires. New spark plug - spark is good - fuel bowl full and screw set as per other carbs. Needle etc all seems fine. Is it an air leak somewhere? Have checked the inlet rubber and o-ring. Can it be the exhaust letting in air? Any suggestions?
Rich

First step - compression test.

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Originally posted by rb968
In the garage - posting via my phone - and my zx9 engine is running on 3 cylinders. We have stripped and cleaned and checked the carb on cylinder 1 but it will only run if i almost completely cover the inlet therefore starving it of air. Then it fires. New spark plug - spark is good - fuel bowl full and screw set as per other carbs. Needle etc all seems fine. Is it an air leak somewhere? Have checked the inlet rubber and o-ring. Can it be the exhaust letting in air? Any suggestions?
Rich

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Bit beyond my capabilities tonight but thanks. Anything else obvious i might have overlooked?

When you cover the intake like that you are effectively raising the fuel/air ratio. Is your carb letting enough fuel through. If you make any changes to your carbs - note down what they were so that you can go back to where you were if you need to.

Steve

cleaned the jets again looks like the pilot jet was blocked . now running on 4 cylinders . phew!

[Edited on 4/2/10 by rb968]