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Doug E.
Doug E., Kawasaki Master Technician
Category: Motorcycle
Satisfied Customers: 2886
Experience:  Professional motorcycle mechanic since 1978. Vintage motorcycle restorer.
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its been running at a high idle speed..fuel line..blown the clutch

Customer Question

i have a kaw 76 kz900. its been running at a high idle speed and all of a sudden I felt some bumping right under the front foot pedals and it started hesitating like i wasnt getting enough gas, so i thought it may have been a fuel line. Now Im for sure its not because now when i squeeze the clutch the rpm goes to about 6 or 7. Wondering if I have blown the clutch?
Submitted: 8 years ago.
Category: Motorcycle
Expert:  Doug E. replied 8 years ago.

First, you need to isolate the problem. When the bike is in neutral, does it run ok or does the engine idle high or erratic? If the problem is also when the bike is in neutral, then it isn't clutch related.

If the bike runs fine but the clutch is slipping when in gear, then it's a clutch problem.

I don't know what has been done to the bike over the years, but the intake manifolds and airbox to carb boots should have been replaced a few times by now due to their age. An air leak at the manifolds or on any of the vacuum lines will produce the symptoms you have. Dirty carbs or a plugged tank vent or petcock will also cause a lean condition and the idle will race up.

The engine noise you felt could have been backfiring into the carbs or the engine will also knock if it's running off balance.

The first thing to do if it's fuel related will be to check the fuel flow to the carbs to make sure the petcock and tank vent aren't restricting fuel. Pull the fuel line and turn on the gas to check the flow. Next, remove the drains on the bottom of the float bowls on the carbs to check for dirt, rust or water. Let me know what you find. Check the hoses and manifolds for cracks and leaks.

Let me know what you find.