Pipes arent hot on one side?????

[Daddio87]

i recently took my 82 Suzuki gs 650 gl apart to replace my gaskets in my engine ( head gasket, block gasket and top gasket) because of an oil leak...i put my bike back together and started it and the left side of my bike ( sitting on the seat looking forward) the pipes are not getting hot.. the right side was plenty hot to the touch while the others were touchable....i do have spark in on that side of the bike when i checked...i broke my throttle cable and haven't gotten a new one and still haven't ridden it yet....the bike did run however but didn't have a lot of gas in it to keep it running..what could cause this??? Thanks

[ChickenGutz]

My first guess is....

A bad coil pack. Then you might check the carbs.

[LarryA_Texas]

coil installation

i recently took my 82 Suzuki gs 650 gl apart to replace my gaskets in my engine ( head gasket, block gasket and top gasket) because of an oil leak...i put my bike back together and started it and the left side of my bike ( sitting on the seat looking forward) the pipes are not getting hot.. the right side was plenty hot to the touch while the others were touchable....i do have spark in on that side of the bike when i checked...i broke my throttle cable and haven't gotten a new one and still haven't ridden it yet....the bike did run however but didn't have a lot of gas in it to keep it running..what could cause this??? Thanks

Do you mean that both of the left side (number 1 and 2 cyl) are not getting hot, but both the right side (3 and 4) are? That's not a coil. One coil should go to cyl # 1 and 4 and the other to 2 and 3. Which coil (left or right) would assume that you connected them correctly after the rebuild, so I'll leave it to you to check the wires and connections. Switching the spark plug leads could be causing the problem you describe but I'd think it would run pretty bad like that. But, it would probably run.

A bad coil, if properly installed, would cause problems on either 1 and 4 or on 2 and 3. If you're curious; both 1 and 4 spark at the same time. With each spark one cylinder has a gas mixture in it and fires a compression stroke. The opposite cylinder has just complete it's exhaust stroke so even though the plug 'sparks' it's more or less wasted since there's no combustible mixture in that cylinder at the time. 2 and 3 work the same way sparking together on the opposite stroke from 1 and 4.

If you're sure the coils are properly installed and you are still getting spark on all four but only getting heat on 3 and 4 then you should be looking at the fuel flow into the carbs and the carb setup itself.

I have often used a thermal sensor to check the relative temps of the pipes to see what is working and what's not. It's a very handy tool and a bit less painful than grabbing the pipe to see which ones are hot. Normally I find them in the 175 to 200 range after a few minutes of running. A leaner mixture will cause it to run hotter. Additional fuel in a rich mixture doesn't all burn and tends to cool the cylinder. Sometimes that helps with setting up carbs.

Good luck