How bad is it when the engine backfires through the carbies? I've only noticed it at idle when the throttle is hit a certain way. Am I right to keep driving it with out worry of a major internal engine failure until I get it tuned?

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Respect mine and I'll respect yours.

I'd be more worried about the engine bay catching fire.
What have you got behind the carbie insulation wise?

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`sneezing' it's called, usually is due to a lean mixture above idle;
accelerator pump not working (Weber etc) or, no or too thin oil in the dashpots on SUs.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I'm only guessing that it's the motor you just put in??? Just a remote possibility, but it could also be sticky inlet valve if engine hasn't run for a while, if so it'll free up.

1310/71 It doesn't have any insulation behind the carbies just the pipercross foam filters.
drmini It's running 1" 1/4 twin SUs, I actually think the oil is to thick.
peterb Your correct about the engine, it came out of a running car then sat in my shed for a few years before getting dropped in and hooked up. So far it's got about 120km on it since installation.

So theirs no real threat of it going bang too soon, I understand super lean engines can burn out pistons and heat the engine up more than normal correct?

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Respect mine and I'll respect yours.

I had the same and it was a blocked jet and fuel line..

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On twins? would that cause one or both to backfire?

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Respect mine and I'll respect yours.

set too lean in mixture

cold start with no choke

sticky/dirty/grotty carby pistons & bells

too light (or low level or no) oil in dash-pots

low float level

do you want more??? or will that lot do for now?



bad condensor

ignition far too retarded

poor ign coil reserve

burnt inlet valves/seats

leaky manifold gasket/carby base gasket

i can go on if you like???



&&& add any of & all of the above in any combination will do it too

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.