Had a major push on the car this week with the sva approaching.

Got the engine going and trying to get some kind of baseline set up.

The issue is backfire through the carbs. It comes as little pops rather than major bangs. It's a 1600 crossflow with a BCF3 cam, twin 40 dellortos and electronic ignition. The timing is at 8deg btdc at 1000rpm. Running on unleaded. Other wise it sounds pretty good.

Pretty sure everything is tight. The only air leak I'm aware of is the header to silencer joint as I don't want to seal that til it's through the body.

Any thoughts?

Id be inclined to run it at nearer to 10 degrees. Im no expert, but mine seem to get very hot with the timing at 8 degrees.

Slight popping can be due to lean running. Are the carbs jetted for the engine and does it pop on idle or between a higher rev range?

Thanks

Shaun

It's popping whilst at idle. It does improve slightly as it warms up.

The issue is backfire through the carbs. It comes as little pops rather than major bangs. It's a 1600 crossflow with a BCF3 cam, twin 40 dellortos and electronic ignition. The timing is at 8deg btdc at 1000rpm. Running on unleaded. Other wise it sounds pretty good.

this is the same as mine but im useing 1300cc pistons and max side valves ,what justs aer you useing and have you tryed drilling your jets with a micro drill set and have you ever used colortune.