crazy ignition problem; misfires - VF1000F


New user here. Hello! Excuse my bad english…

I bought my VF1000F 84´ 8 years ago. Since then it rests in my garage. Has 12k miles on the clock.

I decided to bring the bike back to the road last year (december). Because it´s in good condition, I thought its an easy job; unfortunately not.

Last year I checked everything; changed all wear parts, compression, checked valve timing and lash, the wiring harness for bad connections (alternator plug was lighty grilled), cleaned the carbs and the tank. So, it starts right on first try at the time and runs good. That was five month ago…

So, yesterday I filled the tank, installed the new, fully charged battery and… nothing except a very weak starter turning the engine very slow. WTH?
Ok, I had an RC36 starter siting around, easy enough to change; 15 minutes later a push on the starter turns the engine now fast enough. Jobs done - not.

One ear-shredering BOOM! Massive exhaust misfire.

Roughly 1 sec after releasing the starter-buttom, it misfires in to the exhaust; There is no signs of combustion while cranking. I can smell fuel out of the exhaust. Only misfires as describded after releasing the starter buttom.

I pulled the plugs, checked for spark. There is spark on all cylinders. And it sparks once at the same time on all cylinders short after releasing the starter buttom and the fuel pump turns for one ignition event.

I don´t think thats correct. I pulled the clutch cover and all looks good. Ignition pickups are in place with correct gap and wiring should be ok. Wiring to the ignition-units are fine. Grounds are ok and cleaned.

I have done nothing to the bike in these five month…mysterious.

What can that be?


Hi VF1 kFE,

have you checked the direction of rotation of the RC 36 starter ? It may turn in the wrong direction,just as on the VFS or VF1100S or C…

the slow starter motor on the vf1000 is a common problem, the rc36 starter does turn the correct way for the vf, from memory though the teeth are slightly different so after time it will wear the ring gear and eventually snag and snap teeth from it (been there, done that)…

the ignition system shouldnt spark from all four plugs at the same time, the front 2 cylinders should should fire togerther and the back 2 together… are the plug leads on the correct way, one coil does front, the other coil does rear.

Thank you Pete, I’ll go to bed smarter than when I woke up this morning as I didn’t know the way the RC36 starter turns… :wink:

hi fred,
at times i’m full of usless information…(some say im full of bull sh@t too ;D) i only know as i had one fitted which slowly ate my ring gear :o… :frowning: :frowning: sounds painful