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Discussion Starter #1
have 85 polaris 400 l/c indy , mag side cylinder runs cool at idle, seams to have vac leak, changed mag side seal and top end gaskets , has good compression both cylinders ,checked cdi ,switched wires , carb flanges new , sprayed cleaner all over to find leak , can hold hand over right carb, no change in engine, left side kills engine, any sugg helpful, am i missing something simple
 

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You may already have done all this, but here's some ideas to help locate the problem. This is the process I would take.

"Cool at idle ?" Cool when you hold you hand on the water cover ? At least not as warm as the left side ? If that's the case, I suspect you aren't firing on the right/mag side.

As you know, it's either fuel or spark. Try one more test. Run the motor and pull off a spark plug while it's running. (wear a thick glove). One wire, then replace it, then the other. It should confirm that the right side isn't working. Motor idle speed will slow down if the respective side is working properly.

Then do the plug in the wire test to make sure the plug fires when out of the motor (where you can see it). If no spark, then change the plug for a new one. Then CDI, then magneto.

If spark is okay, carb is the likely source. It may just be gummed up. Remove and dissassemble the carb and soak in a carb cleaner. You can get this stuff at an auto parts dealer. The easy way to go is to take an aerosal can and spray cleaner all over it, inside and out. Spray into every fuel and air passage you can find. Doesn't work as well as a 4 hour soak, but it's a good start.

Good luck. Theres more you can do, but at least start with the basics.
 

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Discussion Starter #3
HAVE DONE ALL THAT ,FIRST CLEANED CARB, SWITCHED WIRES ON MAG AROUND ,HAD TO TAKE MOUNT OFF TO DO , EVEN SWITCHED CARBS AROUND, SEAMS LIKE VAC LEAK, ANY THING PAST 1/4 THROTTLE BOTH CYLINDERS ARE FIRING ,BOTH PIPES ON EXHAUST MAN ARE HOT , LEFT SIDE COOL WHEN IDLE, BOGS ON GIVING THROTTLE DOESNT SEEM TO PULL ENOUGH AIR THROUGH CARB CAN PUT HAND OVER LEFT CARB AND DOESNT KILL MOTOR AS IF DONE ON RIGHT SIDE KILLS MOTOR ( i like capital letters)
 

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first just wanted to say thank you for the replies , problem was with carbs i set the floats to high, wasnt using correct gauge height was flooding out cylinders till it cleared, 2nly checked lower cylinder gasket and gasket holes for air flow are smaller on left side than right and intake pressure doesnt appear to be the same thats why i could hold hand over carb and seamed like vac leak, believe gasket holes are larger because right side has to run fuel pump, again thanks , because i pulled carbs to check and found problem
 
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