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Discussion Starter #1
Ok, so I just rebuilt my z440 sno pro(top end job) and put it all back together. It started up and ran really bad. I ended up finding out that the clutch side piston is not firing. Both cylinders have 150 psi and th carbs are cleaned out. Also there's new fuel lines on the entire sled. I switched carbs and the same thing happened. Eliminates fuel problem. Like I said compression is great. I swapped the spark plug wires around and the same thing happened. I'm going crazy trying to figure this out. Any help would be greatly appreciated!
 

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Grudman
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Well first things first. If you have not check to make sure both plugs have spark. Second check to make sure both have gas getting to each. It got to be something simple as that. Lay plugs over the head of each carb and check for spark.


If spark is ok then your not getting fuel.
 

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if u swapped carbs and wires around and it stayed on the same cylinder its real weird. did u swap at same time or separat
 

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Discussion Starter #5
Well it has good spark on both plugs. So I decided to dig deeper. I have no idea what will cause this or how to fix it, but the cylinder that runs sucks the gas into the engine and the other blows it outta the carb. I'm quite baffled on this one.
 

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I had the same problem with my 98 zl500. Only one would fire at idle. It was a cracked intake boot (the one between the carb and the reeds). $80, a new boot, and I was back and running!
 

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Discussion Starter #8
My intake boots appear to be in good condition. This sled is ported, so it doesn't have any reed valves. It's not getting the gas it needs because it's blowing it all out the back of the carb instead of bringing it into the combustion chamber. Does anyone know what would cause this?
 

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When you rebuilt did you take it all the way down? ( split the cases or just top end?) Have you checked the exhaust on that cylinder for obstructions? A Plugged exhaust port would not allow for the proper flow and would force fuel back out the intake. Just a thought. The other thing might be a timing issue you could have a partially sheared key way on the flywheel.
 

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Would installing the piston 180 degrees off cause this? Most 2-strokes are particular on which way the pistons are installed.
 

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Discussion Starter #14
I installed the pistons with the dot facing the exhaust side. I've been told that's the way they go. I began to split the case but then realized that I didn't need to. Could a bad seal in the case make this happen?
 
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