My first interceptor project

hey,

just bought my first vf 750, its an 84 and i plan to turn it into a tidy weekender with a bit of streetfighter style,

but unfortunatly it didnt take long for me to have problems with it, it hasnt been registered or had a good ride for some time.

When i got it home i gave the battery a good charge and it fired first go, took it for a test ride and the motor seemed good. I stopped it, ten minutes later i cranked it and it was fine, turned it off, came back about an hour later, and cranked it but it didnt fire.

The starter sounds fine, and i dont think the fuels an issue as the insides of the pump are clean and the fuel doesnt smell off plus i added new fuel, when i was moving the tank around the old fuel line split and i only noticed when it cranked when it shat fuel everywhere so i think the pumps working lol.

i had no spark yesterday, today i had a weak spark coming from the rear plugs and nothing from the front, but that didnt last long as now i have no spark at all.

I dont know how old the batter is but it seems to hold charge okay, im getting 12.31v from it when the bikes off, 11.6 when the keys on, and around 10 while cranking

Where would i go from here? a mate rekons its unlikely that both coils would go at once, and thinks its the module mounted near the fuel pump. How do i check to see if it works and how much volts should i expect it to put out?

sorry if its a lot on my first post, but im jsut really keen to ride it again as youd imagine, thanks

 

Run a check on the ohms reading across both pickups/ pulse generators when the engine is cold and when hot. These components can be OK before the engine is running but fail when engine reaches operating temp and will cut sparks. You'll find the proper specs in the FSM, and if you don't have that, you're in trouble. If your pulse generators test OK, its most likely a problem in the CDI box.

Owning a VF will strain your optimism sooner or later.

 

Welcome to the World.
Sounds like your starting off with a hell of a project.

 

its a bit hard to check the ohms when its hot if i cant start it hehe

and it was cheap and i have time on my hands so i dont mind screwing around with it

 

The hardest part about fixing a bike....waiting for the parts you order.

 

While you're waiting for parts, take apart all of the connections in the harness that might have a role in the starting circuits, clean them thoroughly, and put 'em all back together. And put in a new battery while you're at it (IATB).

 

your ignition boxes are in the tail section. check and clean those connectors to the boxes. They often get corroded and don't make good contact and you lose spark. There is also a diode (clutch) in the wiring harness at the base of the tank on the right frame rail. If that's bad the bike won't start. I've never had one fail so I don't know if there is no spark or it dosn't turn over.