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By Adam
#7502
Amal carb, 12k miles, NGK Iridium plug. Running fine of late, got about a mile from home, accelerated out of tightish bend, popped and farted a bit (the bike) then cleared up. about another quarter mile started popping again, got worse, cut out, started and ran at tick over, wouldn't pull at all, did that a few times then refused to start. Plenty of spark. Plenty of fuel at the tickler. Filter at tap had crap in it. Tank off, plenty of crap in there. Cleaned tank and filters. carb off, cleaned and blown through. Fresh petrol, new plug, still wont start. Grrrrr. When it was refusing to start I noticed that as the motor engaged it stalled before swinging over compression, didn't use to do that (don't know if that's relevant or not). Any clues, please, chaps? Adam
By Alan R
#69071
Hi ADAM---bummer, ain't it ??.......Crap in fuel tank?? What sort of crap?? Water---sand / rust---- other ??....Your carb starting jet/s holes are very minute in diameter and are thus VERY PRONE to these small particulates blocking them.....Is it old fuel that's been standing unused for some time ??........Is the fuel tank clean on the inside ??......You might want to consider giving the carb a full Ultrasonic clean...........Been there, done that, know what you're going through
By Adam
#69076
Hi Presto, yep tried both methods, same result. Thanks.
Hi Alan, very fine particles, no big flakes. My immediate thought when I drained the sludge from the tank was that someone might have dissolved a couple of dollops of copper grease in the fuel. Orange-ish sludge and tint to the petrol. Fuel was fresh, bike gets used all year. Cleaned and flushed the tank and introduced clean petrol. I’ll give the carb another blow through with a more powerful airline then try the ultrasonic clean if the problem remains. Thanks. Adam

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