77 pops a little at idle

[leggman]

I finally got my 77 out yesterday and rode it up to the store (about 3 miles) to fill it up with fuel. I t seems to run fine except for an occasional pop at idle. It does have aftermarket mufflers so I am wondering if a exhaust gasket could be leaking?
The carbs before you ask are fresh rebuilds.
Thanks in advance.

[redglbx]

Legg, If it was me I would be checking the resistance across the spark plug caps, they should be less than 5k ohms. What Do you have for ignition, points, Dyna, stock coils, Dyna coils ? Do you still have the resistor at the coils ?

I would also ask what you set your idle mixture screws to, oe carbs or something else ? Have you checked your valve clearances ? Oe spec is .004in but if the bike has been sitting for any length of time I set them at .006in.

That’s a lot but all things that can possibly cause what you’re seeing. Let us know !

[CYBORG]

I would look for air leaks in the exhaust system