5 replies to this topic

[BiBiBiB]

Hi folks,

I have an issue that seems to not be so much of a misfire, but what sounds like gas igniting outside the cilinder. I sounds like ignition of gas in the exhaust manifold and beyond.

What is the correct technical term to describe this?

Secondly: I notice that this happens when accelerating. Happens may e once or twice per ride. First the engine holds back for a second; not producing enough power and shortly thereafter I hear what u can best describe as a tud sounding ignition of gas occurring.

Thanks

Ps: I'm running a Weber carb.

[nicklouse]

Sounds like an ignition issue where a plug is not always firing when it should.

 

so check the plugs. Leads and dizzy for correct function. Not forgetting the coil.

[Ethel]

Bang?

 

 

Isn't it a symptom of a misfire? The fuel can't have burned properly in the cylinder to get in the exhaust (unless you have a enough oil going down your valve stems & a very hot/ restrictive exhaust system.

[Spherix]

So it's backfiring?

[unburntfuelinthemorning]

Back in the day my mates and I with our Minis and Morris Minors used to like to switch the ignition off while driving, coast for a few seconds and then switch it back on, made a lovely bang!  Probably wasn't the best idea but never actually did any harm apart from setting car alarms off in a multi-story car park and making someone I passed on the road think they'd had a blowout.  It only worked with the standard exhaust, once I fitted an RC40 there was no more banging to be had.

[sonscar]

My rule of thumb is pops in inlet is probably too lean,pops in exhaust too rich.As mentioned it could be unburned fuel for many reasons.Air leaks in the exhaust can cause this.Steve..