84 vf700 starts, runs, then immediatly won't start.

So, I picked this bike up a few months ago, and just got to it. 84 vf700, 50kish miles, always garaged, great looking bike. So, charged battery, starts right up with the choke, warms up and runs well, if I blip it while warming up and it stalls, it'll start right back up. If i hit the kill switch or turn off the key, then back on, it will not start again, untill it has sat for well, over night.....

After kill switch, go to start, the tach doesn't move at all, like when initially trying to start. Am i looking at an ignitor box or what now? I'd like to start riding this bike soon, as i'm selling another bike and a car, downsizing the fleet.

what should I check/ replace first (this is the newest motorcycle I have owned, prior to this nothing newer than 76)

 

Electronics boxes don't heal themselves, if the CD igniters were bad then the bike would not start.

So i would guess it's dirty electrical contacts in the key switch and/or the kill switch creating an open circuit.

Do you get voltage to the fuse panel main bus when the key is turned on? If not the key contacts are suspect, if so then the kill switch contacts are suspect. Do you get voltage on the black/white wire going to the coils or igniters?

 

When it quits running, i'd suggest checking the ohmage of the pulse generator coils at the multi-pin plug.


Failing pickup coils can be fine on a cold start, then crap out after engine reaches operationg temp, so no sparks. Occasionally, ignition coils can do the same. My clue is the cool-down interval you mentioned.

 

to be more specific

I go downstairs right now, turn on the key, choke on, starter, starts up! good! if i jam the throttle and it stalls, it will start right back up no problem.

before reaching operating temp, if I hit the kill switch (without ever turning the key) and then go to start again, it'll crank and crank, but no start. wait a few hours, and it will start.

every time i turn the key, everything powers up.

I kinda wish someone had the, "Oh that happened to me and I changed the ------, and it fixed it" guess i'll have to start checking a lot of wiring.

 

Then it sounds like it's bad contacts inside the Kill switch. If you were to take it apart the contacts are likely black from arcing. The voltage to the coils and igniters comes thru the kill switch. If you wanted to troubleshoot it to be certain you could make some measurements such as previously mentioned, but you could just replace the 25+ year old switch and ride on...