>I just bought a motorcycle on ebay. It paid too much. It was supposed
> to run great. It doesn't. I try to take it to work. But I don't trust it. It just dies after about 15 minutes of driving and doesn't seem to have enough umph to restart. Just before it dies, sometimes it backfires. I replaced the battery and went thru a tank of new gas. the plugs are supposed to be new and all the fluids replaced. Its a vn750 '86 kawasaki vulcan with 10.000 miles on it. A
> dealer said this could cost 600-800 to diagnose/fix because its a
> labor intensive problem.

I have heard that it might be a bad ground. But where to I check this exactly? I have also heard it may be a stator. Someone said you have to pull the engine to get one of those in. Is that true? If I put a voltmeter on my battery terminals I get 12.8 volts at idle. I get 12.9 if I rev the engine. Does this sound right?

I just bought an 86 and have also been having some problems with it not wanting to start. Its really hit and miss. Sometimes it starts right up, other times it just sits there and cranks forever. It seems to have the most problems right as its starting to warm up. When its cold, it starts. When its hot, it starts. Its in that 5-10 minute warm up timeframe that it wants to stall and then won't restart.

Have you checked the charging system?
Sounds like you may have a Stator or Regulator Rectifier going or gone.
Look in the Vulcan Verses for a way to check the Charging system.
The Ground people have talked about is where the battery ground attaches to the fraim, it has been known to crack.
I would recomend putting Sea Foam in the tank to help cleen the fuel system.
You can find it at most auto stores.
hope this helps

>I just bought a motorcycle on ebay. It paid too much. It was supposed
> to run great. It doesn't. I try to take it to work. But I don't trust it. It just dies after about 15 minutes of driving and doesn't seem to have enough umph to restart. Just before it dies, sometimes it backfires. I replaced the battery and went thru a tank of new gas. the plugs are supposed to be new and all the fluids replaced. Its a vn750 '86 kawasaki vulcan with 10.000 miles on it. A
> dealer said this could cost 600-800 to diagnose/fix because its a
> labor intensive problem.

I have heard that it might be a bad ground. But where to I check this exactly? I have also heard it may be a stator. Someone said you have to pull the engine to get one of those in. Is that true? If I put a voltmeter on my battery terminals I get 12.8 volts at idle. I get 12.9 if I rev the engine. Does this sound right?


If you rev the engine, your voltage should go up to 14 or so, but the 12.8 v is a promising reading. What's your reading after you've been riding for a bit (as in, when it dies)? It may well be a bad ground - unhook the negative battery terminal, and then check to see that your engine ground lead is clean, tight, and really making contact with metal on the frame (not paint). It should be located on the left side of your bike (facing forward), on the frame, just above the fuse box.


Don't take it to a dealer until everyone here's walked you through some paces. And if it's a charging problem, you've got plenty of company here - we could maybe do a group engine pull!! :huddle:

I had similar issues with my '00. It didn't backfire, but it died a couple of times on me and once it wouldn't re-start after stopping at a store on the way to work.

I ended up only needing a regulator instead of a r/r and stator. There's some good info about checking the charging system with a multimeter in the verses. If you have problems (like I did) there are a lot of folks here that can walk you through it. Like everyone else already said, definitely check all of your connections and make sure that they're clean. If your bike has a wet cell battery, ckeck the vent tube and all parts below the vent tube and see if something has corroded (you'll want to install a maint. free AGM battery ASAP).

Once you get the charging system working right, you'll love the bike. Mine started acting up right after I bought it and I work with the previous owner. The bike never gave him any problems and he offered to give me my money back but I was already bitten by the vulcan bug. I'm glad now that I stuck it out and I love my ride.

Good luck.

When I bought my 86, she was in about the same shape. A new maintenance free battery fixed alot of the starting problems.

If your battery voltage does not go over 12.9Vdc when you rev it up, there is definitely a charging system problem there. After you have checked all the wiring and its good, start with the r/r then the stator.

As previously suggested, check the versus for the test procedure.

My behaved the same, replace the battery, r/r and stator, works fine now.

Jon