KZ 750 LTD Cylinder Not Firing

I did the water spray test on my exhaust pipes and cylinder number 4 is cold. I have spark, tried a new plug and still does not fire. Is there a way to check if that cylinder is getting fuel?

I have cleaned the carbs thoroughly and even had a mechanic at a local shop check them, and every passageway we checked was clear.

Anything else I should check?

Any combustion in #4 with choke on?

I am on my way to lunch break to try some things. I will try that. Thanks.

I tried running it on choke, didn't make a difference. Put in a brand new spark plug NGK B8ES. Ran the bike for 5-10 minutes. Pulled the plug, looked like brand new, no fuel smell or carbon on the plug.

It seems like that cylinder is not getting fuel. Is there a particular passageway in the carburetor to pay attention to?

Thanks.

have you checked to se if you are getting fire to the plug, could be the wire or the plug boot.

brox wrote:

I did the water spray test on my exhaust pipes and cylinder number 4 is cold. I have spark, tried a new plug and still does not fire. Is there a way to check if that cylinder is getting fuel?

I have cleaned the carbs thoroughly and even had a mechanic at a local shop check them, and every passageway we checked was clear.

Anything else I should check?

1) check compression in that cylinder

2) Check plug to see if it's wet

Spark plug is dry, and I cannot smell fuel on the plug. I do have spark in that cylinder. I plan on doing a compression test tonight.

Thanks.

Is fuel getting into the floatbowl?

As known, must have fuel inside floatbowl before any of the carb circuits will function (choke; primary; needle jet). To enter the floatbowl, the incoming fuel must first pass through the float-needle/seat interface.

Am thinking some float-needle seats have a filter screen that might get clogged so as to block fuel flow, whereby the incoming fuel can't get through to the orifice in the seat regardless of whether the interface is otherwise open. If fuel is being blocked by the screen, it isn't reaching the seat orifice, and therefore never getting the opportunity to flow through the orifice around the tip of the float needle and into the floatbowl.

Or, a too low float height setting might be closing the float-needle/seat interface before sufficient fuel is allowed into the floatbowl.

Or, perhaps the float is stuck in the up position and holding the float-needle pressed against the seat so that fuel cannot pass through into the floatbowl.

If in doubt, could test for fuel flow into floatbowl by removing (opening) floatbowl drain screw, turning petcock to ON or PRI and watching for free flow of fuel coming out the floatbowl.

Therefore, would assure that fuel is entering the floatbowl.

Good Luck!

Yes, fuel is getting to the float bowl. I put the petcock on prime and opened the drain screw on carb #4 and fuel flowed freely from the float bowl.

A local mechanic I spoke to suggested checking the valve clearances. Could this be a possibility?

brox wrote:

Yes, fuel is getting to the float bowl. I put the petcock on prime and opened the drain screw on carb #4 and fuel flowed freely from the float bowl.

A local mechanic I spoke to suggested checking the valve clearances. Could this be a possibility?

Yes -- good idea. And would also check compression. Absence of fuel inside cylinder might result from the cylinder being unable to suck mixture from the carb.

Good Luck!