What causes an engine to backfire through the carbs? Would mixture alone do this? I'm certain the timings right on the engine 'cos everything is pretty much standard... I'm certain its running rich- would this allow backfiring through the carb??? I've done a compression test in case it was a carboned inlet valve but the test came back absolutely fine....
I'm pretty sure its backfiring because a bit of my airbox keeps on blowing off. I've replaced it three times(!), each time making it increasingly more securely attached to the rest of the airbox but low-and-behold after this weeks blat, took off the bonnet to find (yet again) I didn't have a top to the airbox!!!! Not the best situation (running without a sealed airbox)....

hmm...

I had a similar issue with carb backfire....even had some impressive flames...

It was caused by the simple fact that the camshaft was 180 degrees out...

You would also get similar symptoms if your HT leads were in the wrong place...

hmmmmmm....

seems to drive okay- but I might just recheck that the right coils are going to the right plugs....

I had backfing.
Turned out the inlet cams were in the wrong posistion, things to be careful when buying a secondhand engine!

My firestorm does it every so often when I blip the throttle whilst stationary.

From my understanding, having the fuel too rich can cause this as well as cam problems.

Air leek on inlet manifold ?

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Originally posted by jacko
Air leek on inlet manifold ?

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inlet valve sticking open, exhaust valve opening too soon, ignition curve sticking firing with a valve open, cam timing......

just a few.

If it is carbs, then balance could be out.