left cylinder runs too cool

buddy

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Just did cam chain, head gasket, rings valves etc on top end. Got it back together and running tonight. Burns clean with no smoke or oil leaks.

The problem is the left cylinder runs cool, you can hold your hand over the exhaust and it is cool, not so with the right cylinder gases are hot. New exhaust pipes show discoloration on hot side and none on the cool side.

I suspect carbs. Can't seem to get the idle down too. Could it be float bowel level on the cool side? Your thought are most welcome. I will dribble a bit of gas into the cool carb and see if that makes a difference - tomorrow.
 
wich one of the three bikes are we talking about here? Sounds like your carbs are out of sync. Back off the idle screw all the way, and bench sync the carbs . You may also have a fouled plug. Or plugged pilot jet. Does it wake up when you give throttle?
 
Only have one bike '78.
Update:
Checked timing, right on. New plugs.

Interesting, with the air filters off and the bike running, if you put your hand over the inlet for the right (good one) cylinder it stalls the bike and you can feel a strong intake of air on your hand.

If you do the same for the left (cool one) bike still runs and no intake air felt on hand.

Engine races and will not idle except with choke partly on.
Tightened the carb clamps still the same. Compression good on both cylinders.

I suspect a leak between the carbs and the head, the rubber sleeves the carbs fit into. Thoughts? Any trick to repairing these donuts or intake pathway?
 
Will check clearances again, but just did compression check and it is 130psi.

Took off vacuum line going to fuel shut off valve and used that point to hold a propane torch as a gas supply - increased rpm and hotter pipe.

Fast idle and cold left side pipe, could this be same problem or two different ones.

This cold pipe on the left side was present before I did the cam chain, head gasket and valves.

Starting to get to me!
 
Hi. I had same problem myself for a while. Turned out it was different hole's in left and wright outlet/exhaust. Since yourse are new, and ignition seems good, maybe the carb diaphrame/membran? If you try to lift the slides they should act the same. When you open throttle both slides should lift ? Good luck
 
Took off carbs, sync was out by sight. Took off rubber ring and carb mount, filed high spots off head mating flange, reassembled with sealant. Checked valve clearance, good. We shall see.
 
Bingo!

Must have been sucking air around the mounting flange. When I filed the head flange the high spots were around the screw holes as I found out from another post. Gotta love this site.

Going to make up a balancer for the carbs next but idles well, both exhausts are warm all in all its is driveable and I can get "On the Road Again".
 

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cool, man. now tune it so you don't hole it.
Oh, I see, you had this bike from 80-82, sold it, then bought it back? That's always cool. brings back memories im sure.
Looks to be in good shape. was it better than when you sold it? or did you buy it like that?
 
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