Having endured this intermittent misfire I tried another 3 things but all at the same time so stupidly don't now know which one it was!
Replaced the rotor arm for the new red one supplied with the Powerspark replacement kit I bought, this was in place of one of the green ones I originally bought from LD
Swapped the magnetic trigger unit back for the old one (having already checked the magnets in both and they are of identical hold)
Weakend the mixture on the carbs by one flat each, even though I tried this before and it/made no difference to the miss fire either weaker or richer.
I think it must be the rotor arm as it's the only thing I'd not changed before but I'm reluctant to put back the green one and adjust the mixture again in case I get back to where I was but the engine is running much smoother now and not missing at all, pulls as it used to in O/d top from 700rpm without a problem.
Happy Days!
Replaced the rotor arm for the new red one supplied with the Powerspark replacement kit I bought, this was in place of one of the green ones I originally bought from LD
Swapped the magnetic trigger unit back for the old one (having already checked the magnets in both and they are of identical hold)
Weakend the mixture on the carbs by one flat each, even though I tried this before and it/made no difference to the miss fire either weaker or richer.
I think it must be the rotor arm as it's the only thing I'd not changed before but I'm reluctant to put back the green one and adjust the mixture again in case I get back to where I was but the engine is running much smoother now and not missing at all, pulls as it used to in O/d top from 700rpm without a problem.
Happy Days!
Comment