Rode 40 miles then it quit...

Could be one of the coils. They heat up during running and short out internally. After coling off a while they’ll work and short again. Thats exactly what happened to my brothers KZ1000. Good luck.

so...life is always the most interesting when you have things you want/need to troubleshoot. it always prevents this..lol
fired the bike today, started right up. checked the voltage at the battery, no real changes beyond about 12.64 at any rpm or with lights, blinkers etc. checked the vacuum line at the petcock, seemed not snug enough,so I redid it with fresh line. went for a small neighborhood ride. ran strong and no hesitations or stutters. got one section of road about 1.5 miles with no houses(so no kids, pets etc) ran it up to about 65 and turned around. shortly thereafter it died. lights all on still. I turned and removed key, opened gas cap(listening for any inrush of air, didnt hear any) coasted to bottom of the hill that I was at the top of(about 300yds) and tried to restart with starter...boom, started right up and I made it home(another 3-400 yds or so) without any further issue. seems like a fuel issue to me. it all started after I filled the tank after having ridden to the low fuel light on the way to get inspected. is there a way to check and/or clean the gas cap? why did it run fine with only about 1/2 gallon in it and then quits when its full?

F64 wrote: I helped someone years ago that had the charging system issue. It would die then he could restart it after the battery recovered, but it would run for less and less each time.
Anyway, find your meter.
Set your meter for DC V.
Black meter probe on the neg battery post(the metal part of the battery not the connector for the battery cable)
Red meter probe on the positive battery post
Note voltage

Fire up the bike
Note voltage
Raise to 3000rpm
Note voltage
Raise to 5000rpm
Note voltage

Let idle
Turn on high beam and one turn signal
Note voltage
Raise to 3000 rpm
Note voltage
Raise to 5000rpm
Note voltage

Turn off bike

Your readings should stay above 12.6.
At idle the bikes usually don't charge. You have to bring the rpm up a bit to get the charging hence the 3000,5000rpm. If the battery is overcharging, the voltage will climb well above 14 with the higher rpms.

You turn on the high beam and turn signal to see if the charging system can handle a bigger load and maintain the 12.6v to 14.4v.
Ok, let us know what you find.

There are 2 bowl vents on your carb rack. Should be on carb 2 & 4. They need to be open to atmosphere. Either no hose or a hose that is open on the end. #3 carb should be your vacuum to the petcock. If bowl vents ar capped you build pressure in the bowl and fuel can’t easily flow into the bowl. Speediders like small holes to build homes. Check them to rule that out.

Your voltage should have gone up with the higher rpm. Battery is not charging.

2 and 4 are short hosed, but open. I have the vac on #1going to petcock. I will switch and cap #1. Maybe just running out of fuel...that would be kinda murphys law..lol..thx

Mikaw wrote: There are 2 bowl vents on your carb rack. Should be on carb 2 & 4. They need to be open to atmosphere. Either no hose or a hose that is open on the end. #3 carb should be your vacuum to the petcock. If bowl vents ar capped you build pressure in the bowl and fuel can’t easily flow into the bowl. Speediders like small holes to build homes. Check them to rule that out.

So if not charging, would that be stator or something else?

F64 wrote: Your voltage should have gone up with the higher rpm. Battery is not charging.

rebreath wrote: So if not charging, would that be stator or something else?

F64 wrote: Your voltage should have gone up with the higher rpm. Battery is not charging.

I’d think reg/rec first. Hopefully F64 can let us know how to test that. If not I’ll look up the factory test procedures.

Something is note adding up. The vacuum to petcock should be on #2. Can you post a pic of your carbs. Your bike should have VM24 with accelerator pump.

Are you running pods or a stock air box? If it's an air box, is the breather hose connected? Is it getting plugged at all?
Check your sight glass. Ard oil levels correct?
Sounds similar to when my crankcase filled with fuel. It would still run okay until it would start filling the breather hose, and immediately choke itself out. I could let it sit, oil/gas would flow back into the case clearing the breather, and it would start again.

Suspect electrics.

Whenever I've had a similar problem, it's been after I'd had the tank off the bike and disconnected the battery, and hadn't tightened up the battery terminals.
The bike will run when the leads are touching the terminals, but when running it will bounce around and stop touching.

Make sure battery terminals and connections are tight.

Guys at z1 showed me via parts pic that 2 and 4 are open to the world. They do not have any vacuum pull . I left these open with lines curved down. 2 also has a vac nipple they said should be for petcock and yes it has an accelerator pump on the bottom of #2.

Mikaw wrote: Something is note adding up. The vacuum to petcock should be on #2. Can you post a pic of your carbs. Your bike should have VM24 with accelerator pump.

Stock box, breather connected. Changed oil and filter yesterday in fact. No gas smell and oil looked pretty clean. I will get a sight glass pic for you later today

Kaylinator wrote: Are you running pods or a stock air box? If it's an air box, is the breather hose connected? Is it getting plugged at all?
Check your sight glass. Ard oil levels correct?
Sounds similar to when my crankcase filled with fuel. It would still run okay until it would start filling the breather hose, and immediately choke itself out. I could let it sit, oil/gas would flow back into the case clearing the breather, and it would start again.