Ok Long story...
Its a h1D that ive had 35years. Doesnt get ridden much, i just work on it
Lets just say everything has been done at least twice.
About 7 odd years ago it started fouling one plug and i stopped riding it as interests were racing motorbikes so i just put it away.
Then about 4 years ago i removed the crank because it is a rebuilt one. I wanted it for my race bike. The one in the race bike worked fine but it was unknown.
Now ive lost interest in racing bikes (15 broken bones) So 6 months ago decided to reassemble the D with the crank from race bike. Didnt do a leak test but seals are tight on the crank which was good enough for me. Did a oil pump output check and all three are the same. So figured it was jetting.
Ive been pissing around with jetting and been either side of sweet spot on needles and plugs look great.
Its back to totaly stock bar K&N filter and Ivans jet kit. 105 mains
Then a few weeks ago it all of a sudden got really bad and started missing on all cylinders at higher revs, so i suspected ignition problem.
I have been through everything in electrical system, checked connections, tested all components with meter. replaced the coils. Grounds are all good.
I made the CDIs and rectifier about 15 years ago, they test fine and havent done much work. So i put a new regulator in and that fixed THAT problem.
So now i am at described in first post. The bike goes best it ever has, just random cutting out in power band. Not always though.
Its not a blocked tank cap breather. I spend lots on new plugs
I am slightly stumped and can see only two thing left to do...
Check actual fuel level in the carbs. Previously i just set the float height on low side. (least amount of fuel in bowl)
Or do a real time check on the spark, although i am fairly confident spark is good and its not a easy thing to do while riding the dang thing.
Thanks.