81 kz650 cyclinder #2 not running

Hello riders,

I was riding my 81 kz650 all of a sudden I noticed loss of power..

I checked and noticed gas coming out/dripping of the exaust.AFter more investigation I coudl see exaust pipe #2 not getting hot at all while bike is running.

I checked spark ok, change spark plug as well. Did compression test( tough maybe stuck valve) its the same as others. Cleaned the carb just in case all passages are clean. still same issue..??

what could be my problem?

- Compression ok ~ 120 PSI
- Spark ok
- new plug
- gas leaking from exaust
-cleaned carbs


Could it be the CDI if if the spark looks great?

Sounds like a bad float valve inside the carburetor.

If it was the IC it would cut out two cylinders not only one.

ditto to what otto said also you might want to check you oil and see if any gas is in the sump.

ok to test i will swap float valve from 1 to 2..if thats it will replace them all..


thanks alot for the tip

I know you said you had spark.

The presence of spark doesn't necessarily indicate good spark. I solved an intermitent firing problem by redoing the coil & plug wire connections at all points from the coils to the plugs. The spark plug wires unscrew from the coils. The connections become poor from oxidation over time. Some dielectric grease wouldn't hurt. If there's a lot of the white crusty corrosion, you might need to nip off the ends of the wires - be careful about removing too much though so that they don't end up too short.

Fixed My problem.

It was in fact the Wire from the Coil to the plug.
i changed it and all is good now..


Thx alot for all the tips..

I really appreciate all the tips on this forum..