One exhaust running hot, One running cold...

[ChickenCeviche]

Had the the engine running great. Then I️ pulled the crank case cover and the cover on the left side off to repaint. Had a bit of trouble reassembling the left cover, and the components within, but felt like I️ finally got it back on correctly.
Then I️ fired her up and it felt like I️ was only getting exhaust out of the right side. Took it for a spin around the block and I️ was getting exhaust out of both pipes, but I️ was only getting heat out of the right side. Same amount of exhaust coming out of both pipes, but absolutely no heat out of the left exhaust. Even after 10-15 minutes of revving it in neutral.
I️ wrapped the pipes when I️ painted the covers and the right one was smoking but there wasn't any heat coming out of any part of the exhaust on the left side.

Does anyone know what could have possible happened? I'm at a total loss.

Any advice would be greatly appreciated. This is my first build, I'm a total newbie.

Thanks guys.

[G-Man]

First of all, what bike is it? CB (two sets of points/coils) or CA (one)

Have you looked for fuel or spark on that side.

What color are the plugs.?

Have you tried swapping them over?

Why the exhaust wrap? Trying to spoil the exhaust gas flow? :-)

You have to work a little to get us some evidence....

G

[ChickenCeviche]

Hey G-Man.
Sorry its a 1965 CB77 so two coils. I️ actually didn't check for spark or fuel on that side. It was the end of a frustration 9 hour session working on it so we just packed it up. Everything was working perfectly fine the day before but we did rewire the headlight and tucked away some wires so maybe we knocked something loose around the coil. I️ just wanted to ask you guys before I️ went back in the garage and start trouble shooting. So the first thing I'll check for is spark and fuel on that side.
The wrap was because the pipes are pretty rusty so I️ thought it'd look better to wrap them. It looks ok. Thanks for your help. I'll let you know how I️ go.

[DJM]

If no part of the exhaust is getting hot even after extended running it's a fair bet that the engine is actually only running on one cylinder.

Some headers are double skin but not all so it's just possible you have one of each but the silencers should still get equally hot.

You will feel 'exhaust' at the end of both cylinders but on side is probably just cool air being pumped through the cylinder.

If the exhaust isn't even warm the cylinder isn't firing.

[Txturbo]

Most likely cause is the jets clogged up in the carb on that cylinder.

[mike in idaho]

Put a new spark plug in it. That's the easiest/first thing you should do. Cleaning a carburetor won't fix a gas-fouled plug.