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Discussion Starter #1
alright guys, im stumped for the first time, my buddies sled that i am fixing is a '95 ZR 580 Carb., now he claimed he lost compression in one cylinder, now there isn't any cracks at all, i magnafluxed them. now what gets me is it still runs but when you hit the throttle it wont even go. could it just be a bad gasket?

PLEASE TELL ME ALL INFO YOU GUYS KNOW, ANY HELP WILL BE GREAT.
thanks
 

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If it runs its because it has compression in 1 cylinder. When you need the power the second one is just crap so....

It could be many things for just one cylinder. Could be a gasket(put soapy water around the case to check this). It could also be the rings. Put the cylinder at it compression stroke and have the pressure guadge in it. It should read whatever. Then wait like 2 to 3 hrs and check it again, if it droped more than 1-2psi its rings or a gasket. With that old of an engine it might be good to just replace all of those things so you dont have to worry about it.
 

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Discussion Starter #3
Yeah but he said that the bad cylinder reading was only like 10 psi, so i could imagine it can be a ring, but what did you mena about the soapy water?
 

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could be piston to, isnt really gaskets on those engines they are like an o-ring
 

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Even on a cold engine 10 psi is not acceptable. You have a serious problem. Normal psi should be 120 minimum. You could have a hole in the piston, or the rings could be totally gone. The best case would be a bad piston, because then you could just replace that... at the worst you could have a bad piston and cylinder, head damage can occur if things get bounced around in there. If the spark plug tip had any metal on it when you took it out.... youve got a good problem.

Might as well drain the coolant, remove the head, and remove the suspected cylinder, check it out, you will know very quickly what the problem is.

Did you test both cylinders for compression? you could have a bad gauge.
 

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Pretty sure thehawk is heading in the right direction. Check your gauges to make sure, if it is fine then your looking at something major.

Check the rings, you may be missing one. Pull of the exhaust/carbs and look into the cylinder as you turn it over.
 

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Discussion Starter #7
Alright guys, i took the jugs off and sure enough in the pto side cylinder the rings were fried. Luckily it didnt damage the cylinder wall barely, i was able to hone them out pretty good. So i just put new pistons and rings on, and gaskets. And the sled runs perfectly. thanks for all the help. by the way, those 580's are very fast-probably because there is no real air flow restrictions.
thanks guys
 

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Glad to hear you got it running again.
 
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