Motorcycle Questions? Ask a Mechanic.
Hi, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, are both cylinders firing evenly? ...exhaust equally hot?
Can you try....
After a fresh start before fully warmed up, feel but not touch if the cylinder heads heated up and then compare. A cylinder that is not firing would still be cold compared to a cylinder that is firing.
The cylinder head would be the top most part immediately above the finned part. The 2 cylinders would be forming a Vee thus 1 of the cylinder heads would be underneath the front of the fuel tank while the other would be below the rear part of the fuel tank.
We have now identified the front cylinder as not firing.
That only 1 cylinder is firing would cause the "...bogging down...sounds different...no power...".
Now let's see why the front cylinder is not firing and determine if it is electrical/ignition related or fuel delivery/starvation issue. Proposed preliminary checks (if have not been done):
Sorry; Internet was down.
That there is "...good fire..." would eliminate ignition/electrical as a possibility; not even a bad connection.
This would then make a likely fuel delivery/starvation issue; a carb concern.