750 misfiring

Previously geoff_gowers wrote:

My 750 Commando has been misfiring and I initially thought the cause was fuel thus the carby was cleaned, checked and float level reset. On checking the plugs I discovered that they spark initially and no spark thereafter. The ignition is a Trispark. Battery has a full charge. Given these symptoms is the problem likely to be the Trispark, the coils, faulty wiring, otheretc. Comments welcomed please before I go to the workshop.

hello did you try the spark plugs in somthing else, to see its not the plugs,

alway start at one end and work inward that how to fault find

yours anna j

Had a very irritating misfire once on my Mk 3 850. Went through a steady process of ignition parts replacement , one at a time- first plugs, then condensors , next coils - nope , misfire still there - finally traced it to a short in the wires from contact breaker to coils where cable had been rubbingagainst frame downtube. Good luck.

A 750 Commando that i had in 1973 onwards developed a misfire that I found hard to trace until I ran it in the dark. I could then see sparks coming from one of the coils. On closer inspection there was a hairline crack in the bakolite end cap causing a short to the casing.

The Trispark has all it electrical gubbins in the heat of the old points chamber as per the Boyer MK1(which failed due to heat issues), for this reason I would not buy one for a non Trident. On the Trident triple version the electrics is outside the engine and it is the best ignition system for the Triples.