GL1000 popping through exhaust

[ntintruder]

Cleaning up a 1978 GL1000. PO said he checked timing etc.. The bike idles well but crank it up to 3000 rpm and it starts to pop. Exhaust system is after market. I'm going to replace plugs and points and timing belts, etc. but I was wondering if there is anything that would be the likely cause of this on a GL1000?

[Grasshutperformance]

Cleaning up a 1978 GL1000. PO said he checked timing etc.. The bike idles well but crank it up to 3000 rpm and it starts to pop. Exhaust system is after market. I'm going to replace plugs and points and timing belts, etc. but I was wondering if there is anything that would be the likely cause of this on a GL1000?

Not enough data here. Does it always pop? Only on accel? Only on Decel? Just one pop, multiples, steady even or random, etc.
Tom

[ntintruder]

the popping is really a loud crack coming intermittently when you hold the throttle open at around 3000 rpm not on decel.

[Grasshutperformance]

What shape is the ignition in? Does it do it while riding? Or just sitting still? It could be that you get a misfire and the raw gas and air ignites in the exhaust and that could be what you hear. Hard to say for sure without seeing the bike, but that is one possibility.
Tom