Sudden Poor Running

Well done, Scott. Follow ups are rare. Thank you.

Ugh I'm been stumped twice to get started after a fine ride to work - took a while to trace to shorting coil internal case which earthed to frame killing spark so had to put clear packing tape around a coil with it hung outside of clamp mount to get home and get another on. A number of times me and buddy running along fine then a few seconds misfire then dead that turned out to be bad charger wire connections so voltage when lower and lower till no go but the misfiring intervals as some speed blew out slienter rust crust at following rider. Carb slides can loose a hunk too that both messes with mixture and valve on seat sealing. Once turned out to be a bad tail light earth strap shorting a little intermittently over months and no way to reproduce it-trace it during these months, till just quit one day a 100 yd from shed - so went blank mind irrational-angery and picked easiest place to look with Sherlocks moto ringing in my head. Miracles do happen all the time but helps sharing check lists to stay current.

kernel65 said:

I found the problem. But will answer questions folks mentioned.

The problem were the COILS

Click to expand...

COILS plural ??

Maybe this has more miles to go yet, coils don't usually suddenly go bad in pairs..... ?

[/quote]


COILS plural ??

Maybe this has more miles to go yet, coils don't usually suddenly go bad in pairs..... ?[/quote]


They both tested the same at 1.8. If I had to guess I would say the right coil could possibly be real culprit. When the symptoms first arose in that half mile from my house, it felt like the right cylinder was not firing or was only intermittently firing. I was unable to replicate the same thing again. Both cylinders ran equally poor, but I have noticed the left seems to be more of the dominant one if there is such a thing. It has always required less air screw adjustment than the right to achieve the same results. If comparing the left and right hand plugs, you might say the right was slightly more fouled. But if it was a single coil to blame, why would both plugs load up, or should they?

Time will tell, and if the same problem arises I will report back.

Scott

worntorn said:

Finally a thread where someone reports back on the fix. Scott, as you mentioned, most often the thread is started andpeople respond with all sorts of good ideas. The OP usually keeps reporting while the problem persists, then when finally fixed, rides off into the sunset without ever adding to the data base by telling us what made it go again.

I believe the score for electrical over Carb problems is something like 9,057 to 8 :mrgreen:
Coils can also be OK cold and go bad as things warm up.
Glen

Click to expand...

+1 regarding the feedback ..... when the OP rides off into the sunset, he leaves us all hanging.... thanks Scott.

This makes electrical over carbs 9,058 to 8

Slick

Its pretty much a moto on other vintage forums when it sounds acts smells like fuel issue always suspect electrics first.

Glad you found it Scott. Coils can break down on the HV side without ever being able to measure anything DC wise. It's been my experience that ignition problems are hard to trace with an ohm meter. Lower RPM also would put more of a load on the coil than high RPM, no? I wonder if it's a result of the Pazon working the coils more than the points? Anyhow, something to keep in mind. It's almost like we have to keep spare everything in case something goes wrong. When my coil failed, it just opened up and wouldn't start, that was easy enough to find.

When Coils go bad they sometime fire up when they are cold and as soon as they get hot is when they die, I have been through a few coils over the 40 years of ownership but now have gone the Joe Hunt maggie way, been on my Norton for over 5 years now and haven't even touched it yet, still fires up frist kick every time even when its been sitting for a few weeks, so glad you found the problem and good feed back as well, well done.

Ashley