The misfire events are very short lived, like 30 seconds or so, so the plugs would be dry after running quickly, the next time it has a fit ill take the plugs out and see if which cylinder its happening on.

 

And the spark plug wires are gripping the threads of plug tops tight, right ?

 

Exactly! Not a true misfire like bad wires or connections. Comes and goes but only at low RPM. After the stumble she runs great to red line. Before I rejetted and did the coil mod, she would stall when turning at low speed in parking lots and I would come close to dumping her due to the abrupt stall.

You could drain the fuel and try a different pump and see it she runs better.

 

OK so stick coil mod done,what a massive difference, started right up from cold and the idle was rock solid!

What wasn't so solid was the newly developed rattle from the top end. Discovered a valve adjuster lock nut loose and awol which is not so fun so waiting on a replacement to arrive at the local dealer before I can see if the new coils have resolved the problem.

 

Good news and bad news at the same time. If the old nut is not up top, it may have dropped down the Cam chain well and is in the sump. You can retrieve it by, pulling the plastic, pull the radiator back (removing bottom bolts), removing head pipes and then you can pull the sump plate off and take a look. Maybe drain the oil and it may come out.

The better running may have been due to old wires (Sprock's recommendation)that get offset by the stick coils. New wires are so much more $$$ than the mod and you get a hotter spark.

 

Yeah my thoughts as well, I'm hoping that the nut is sitting in the sump somwhere as its nowhere to be seen I have bought a replacement and will keep an eye for it on my next oil change.

I had already changed the plug leads and caps for new NGK ones, the only old part of the ignition system were the coils themselves so they must have been old and worn out.

 

New adjuster lock nut fitted yesterday and went for a ride today with the stick coils, problem gone and cold starting is much easier! Thanks all for the advice!

 

a strong earth magnet epoxied to flexible wire might help you fish the nut out
of the oil pan/sump through the drain hole - just saying

 

Im hoping it comes out with the next oil change

Engine is running sweetly now

 

Should do ..... just avoid stunting for a bit