Intermittent spark and backfire 78 gs750 stock

[Guest]

Hey everyone.
I bought this bike just over a month ago. Ive completly cleaned and rebuilt the carbs, stock needles and jets, new orings and intake orings. Did a valve shim adjustment "thanks shim club!" went through and adjusted the timing staticly and with a light. I have the guage set to sync the carbs but havnt done it yet because of below issues.

The problem or problems im having are...

1. I pulled each plug wire and checked for spark. Seams really weak to me. And when I use my timing light to check timing, the spark "flash of light" isnt consistent. Seams to be not fireing every time it should. Plugs are gapped to .28"

2. Its backfireing quite a bit mostly through the exhaust and sometimes through the airbox.

3. I think I might have an exhaust leak at the header flange. New seals on order.

4. Seems to be running rich, I can start it without the choke.

5. Rough idol and lacks power and hesitates low end. One I rev up, it gets better, but I can still feel backfire.

Ive adjusted my fuel pilot screw to only 3/4 out which seemed to help some.
I was thinking I might need new points and condensors, but I was thinking of doing the dyna s instead?

Any help would be greatly apreciated.

[MisterCinders]

I assume the plugs are not fouled, etc.

You might just need to clean up and check the points gaps. If your points are beyond that or otherwise in bad shape, change over to Dyna. I like mine.

Another (much cheaper) modification to consider is the power path to your coils. Check all the connections, battery strength, charging system etc. The stock wiring for the coils runs all the way through the handlebars and switches before reaching the coils. For about $10 in parts and 15 minutes of work, you can install a coil relay that feeds power to the coils more directly.

http://members.dslextreme.com/users/bikecliff/images/coil_relay_mod.html