Trying to find correct jets

I have been trying to fix up a bike that dies when I give it any throttle. It was suggested that there was a block somewhere in the pilot system. I went through and checked today and all the passages are clear, so I don't think that that's the problem. I checked the sizes of the jets, and what I found is that the primary main jets are #65 when my book says they should be #70, and the secondary main jets are #88 when my book says they should be #85. My question is how much of a difference would this make? Could this be the problem? I don't really have any experience with jets.

Also, how do I check the sizes of the air jets when I can't remove them?

Thank you in advance for any help/advice you could give me.

srosebrock wrote: I have been trying to fix up a bike that dies when I give it any throttle. It was suggested that there was a block somewhere in the pilot system. I went through and checked today and all the passages are clear, so I don't think that that's the problem. I checked the sizes of the jets, and what I found is that the primary main jets are #65 when my book says they should be #70, and the secondary main jets are #88 when my book says they should be #85. My question is how much of a difference would this make? Could this be the problem? I don't really have any experience with jets.

Also, how do I check the sizes of the air jets when I can't remove them?

Thank you in advance for any help/advice you could give me.

been trying to fix up a bike -- any history of satisfactory running before needing to be fixed up?

It was suggested that there was a block somewhere in the pilot system. -- imo, a likely suspect.

Imo, jet size isn't the problem.

If the air box has been replaced with pods, would start by trying to obtain an air box.
Reportedly, the KZ440 is notoriously difficult to tune when fitted with pods.

Good Fortune!

The guy I got it from said it sat for like 9 years before he sold it to me. It ran before that though.

The bike has the stock airbox on it, no pods.

I did adjust the float level when I had the carbs apart last night, it was several MMs off, I don't know how much of an effect that would have.

srosebrock wrote: ...stock airbox on it, no pods.
I did adjust the float level when I had the carbs apart last night, it was several MMs off, I don't know how much of an effect that would have.

Should assure correct FUEL level via clear tube test with carbs fully assembled and in level position.

Forget about the upside-down-on-the-bench-measured-float-height with the bowls removed, as this is mostly wasted effort, although it might possibly allow a resulting FUEL level somewhere in the ball park of correctness.

The correct "float height" is whatever results in the correct fuel level.



Good Fortune!

KZ440 likely has CV carbs, different from the manual slide carbs illustrated in the previous post.

On some CV carb designs, a slightly different clear tube attachment is used, such as onto the nipple from bottom of float bowl.

Some of such CV carb nipples function along with the "drain screw" as an overflow outlet when the drain screw is in its normally tightened position, and as a float bowl drain when the drain screw is loosened.

Am uncertain about the carbs at hand, but the clear tube test principles remain the same.

Good Fortune!