1981 KZ440 Overflowing Carbs Gas in oil

A friend of mine has a 1981 KZ440 LTD Belt Drive that she was riding up till about a month ago. She had commented that it would occasionally spit a little excess gas from the overflow. After parking it for three weeks she went to start it and immediately it started pouring gas out from the carbs whether it was running or not.

I thought perhaps the floats were stuck so I went over and pulled the carbs apart. The inside of the carbs looked clean enough but I went ahead and cleaned them anyway since they were off the bike. While the carbs were off she changed the oil and filter and after verifying the oil (after cranking the engine over a few times)level was proper I remounted the carbs and tried to fire it up. Gas started pouring out of the carbs both from the overflow and from what looked like the boot between the airbox and carbs. To make matters worse I glanced down at the oil window and was greated with cream colored oil. I told he no to start the bike again until we figure out why the gas is overflowing and we change the oil and filter again.

Thoughts?

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At least one carb float valve is leaking, maybe more, often from crud or grit interference with sealing between the float needle point and seat orifice. But sometimes a worn float needle is the culprit.

Overflow circuit is probably also clogged or being overwhelmed by excessive fuel being allowed past the float valve.

A good cleaning might resolve the problem without needing to replace any parts.

Hopefully, an in-line fuel filter is already fitted.

Good Luck!

I am going to order a new float needle and take another shot at the carbs I guess. I had originally thought that as well. I should have swapped the needles during reassembly to rule that out as a cause.

Make sure the float is OK. All you have to do to get it to seal is polish the tapered end of the needles dead smooth and the brass seats as well. I put them in a low speed hand drill and spin tham and use 600 paper until they are shiny smooth. Then set the fuel levels and they will not leak.

This polishing is normal maintenance on these carbs. The brass oxidizes slowly and then doesn't seal as tight. You need to turn off the petcock if you are leaving it for hours, just to make sure. I always turn mine off after I park it in the garage.

shadowbethesda wrote:

I am going to order a new float needle and take another shot at the carbs I guess. I had originally thought that as well. I should have swapped the needles during reassembly to rule that out as a cause.

I think Keyster makes rebuild kits for these and they are really a good deal. I think they are $18 but have all the needles, jets, gaskets, etc.