420C backfires through carb?

[CCWKen]

Is it normal to have a slight pop from carb? I've done a complete tune and overhauled the carb. The timing is set right but I still get a slight pop from the carb at all speeds. I'm wondering if someone may have set the valves too tight? Any one else seen this problem?

[JD40c]

My 40C never backfires through the carb, ever. If you're sure the points/condenser and sparkplugs are all good, I'd start looking at the carb.

[Lavoy]

It wouldn't be an all bad idea to check the valves just in case. If one is too tight, you will eventually burn it.
Lavoy

[CCWKen]

Just an update on this condition. I was going to post sooner but got tied up working on other stuf and it slipped my mind.

I adjusted the valves. That helped a little but after running it under working load conditions for a short time, it smothed out. I suspect there may have been some carbon under the exhaust valves. (Rebuilt the carb earlier because of loading up.) After running through a can of top cleaner and re-adjusting the valves, it runs supurb!