engine cutting out and now it died on hwy???

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Hey all -- still working on getting a new to me bike ride-able -- thought I had it were I could ride to work -- but it died at highway speed and left me stranded. left me stranded. Tow truck to house.

Problem: recent past it rides fine at lower speeds -- at highway speeds it starts to cut out, feels like a surge but more likely the enginer was just cutting out. worked on it over the weekend and thought it was better. rode to work and still felt the cutting out at 65-80MPH and associated RPM. uncomfortable but still functioning. then on ride home, Hot humid day, It started cutting out and then just fully cut out, had to coast off Highway. got it going on service road and tried to ride home slow on back roads since below 45 it has been fine, but then the engine cut out again and left me stranded. Battery fine and it would still crank via starter, but would not start up. let it cool some, but still would not start. tow truck got me home, once in the garage it started up pretty easy, and will start now. Im at a bit of a loss. Hope someone can say, "yep, seen this and your problem is this"

2002 vmax
- battery is charging 13.5 V (not great but the battery is still turning the engine over). Battery never died through the whole stranding -- I kept trying to start for 1.5 hrs while waiting for tow truck. Starter kept turning over engine but no fire, engine just turned but no vroommm, then started the bike once off the tow truck. I did try choke on and off several times as the bike cooled.
- temp was good the whole time
- when by the road, I didn't ever hear the Fan (???) --- but temp was showing moderate, a little above midpoint.
- checked stator and shunt R/R last weekend -- they are fine
- RR run straight to pos terminal. crimp removed, cleaned all contacts and applied elec grease to all connectors between stator and battery and cleaned ground connections.
- new speak plugs. plug wired appear in good shape --- descent spark on the plugs
- good fuel
- synced carbs last weekend -- seemed better but then problem started creeping back in and got progressively worse.
- new fuel filter -- cut old one open and did not find rust.
- compression good -- checked last week before I changed plugs
- Air filter is clean
- RPM does not seem to matter -- can rev up at lower speeds in lower gear and seems to have no issue -- when its not completely cut out.
- thinking back, seems that it cuts out when I release the throttle or slow down if Im going at any kind of speed. i.e., going fast, let off the throttle, and engine seems to cut out, and takes a moment to start pushing again. Perhaps the engine was in fact dying when I let off, but momentum of the bike "push started" it again after 2-3 seconds. dunno.

need 4 things: compression/fuel/spark/air
- compression is good
- I think spark is good -- but could not check when I was by the road.
- leaves me with fuel and Air.

suspicions:
- Fuel -- perhaps the aftermarked fuel pump -- should I get a OEM fuel pump (not cheap if current one is fine)
- Air -- have not rebuilt carbs yet or even dug down into them -- but works at lower speed up to around 55ish in any RPM
- spark- ??? reasoning thats not it, if it was one plug or coil, then other three would have started bike or kept it going -- I would have had the bike at least try to fire -- something killed the whole system -- is there something between all four coils and the battery that could go wrong.
- odd thought -- removed crimp and replaced with butt splice that has the solder in the butt connector -- when I replaced the crimp it didn't look bad. possible the butt splice connection I made was not good and I should solder in wire and shrink wrap. but to me seems unlikely given it runs ok at lower speeds.

goign to start trouble shooting -- will probably replace fuel pump just to rule that out. then open up the carbs and start poking at those. bike had mostly sat for 2 years prior to my purchase a few weeks ago. I drove it home from purchase site (5 hrs highway). was cutting out then as well, but made it all the way home.

Thanks for any solid leads. Brett
 
I bet if you try to read the resistance of the hot 2 wires for the pick-up coil, you get an open (infinite) circuit when the bike quits. Let it cool-down, the circuit becomes continuous once again, and the engine will start. But, once it gets hot, the continuity breaks, and the engine won't start. The bike will turn over, but not start (when hot).

VMax electrical resistance data.png
https://dn790009.ca.archive.org/0/i...ice-manual/yamahavmaxvmx12-service-manual.pdf
Refer to chapter 7, p.29 (Electrical; pick-up coil test) page 332 of 405 pages according to the .pdf page count

1691896664397.png
 
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Sounds like a fuel problem to me. I had similar symptoms on my FJR1300 and turns out there was a filter inside the fuel tank that gets clogged up. Cleaned that and it has been fine ever since. So a new fuel pump may solve your problem, if not just look at every stage of the fuel system from the tank to the carbs to ensure that fuel is getting through. Good luck!
 
If it rides fine at low speeds i.e. you could ride for as long as you want, then I doubt it is a pick-up coil. Worth testing if only to rule it out.
Please, please, please DON'T replace the fuel pump unless you have confirmed that it is faulty...unless you want a spare fuel pump?
 
If it rides fine at low speeds i.e. you could ride for as long as you want, then I doubt it is a pick-up coil. Worth testing if only to rule it out.
Please, please, please DON'T replace the fuel pump unless you have confirmed that it is faulty...unless you want a spare fuel pump?
thanks Max -- I just got back rebuilt carbs from Danny Unwin (nice work). now the bike will only start briefly with a fully charged battery. I can not rev it or it will die. It dies shortly anyway and the battery is draining. after it runs for a few seconds and dies, It will not restart. the battery voltage drops (last time to 11.7v), engine will turn over but not start. starter will quickly start rattling but not start. so Im back to suspecting the charging system WAS failing but is now completely kaput and the engine is trying to run off of battery alone and can't do it for more than several seconds.

before I check the pickup as fire-medic noted above, can you answer a question on fuel pump. It has an aftermarket fuel pump by Quantum Electric. Fuel line from pump to carbs is clear so I can see in it. After I put the carbs back on I noticed a vibration in the fuel pump after I turned the bike on and as it started I saw some bubbles moving backward into the fuel pump. I don't see them now and am assuming that was just the fuel system getting rid of air since it was just reconnected. I don't figure I have to worry about the pump cavitating or that would make a lot of noise (I assume). I don't want to try to take the fuel line off the pump since it seems to be super adhered, almost like it was glued on. I tried to slide it off and its not budging, would have to cut it and then dig out the carbs again since there is no slack in the line. any reason to suspect the fuel pump in your mind.
 
I bet if you try to read the resistance of the hot 2 wires for the pick-up coil, you get an open (infinite) circuit when the bike quits. Let it cool-down, the circuit becomes continuous once again, and the engine will start. But, once it gets hot, the continuity breaks, and the engine won't start. The bike will turn over, but not start (when hot).

View attachment 90642
https://dn790009.ca.archive.org/0/i...ice-manual/yamahavmaxvmx12-service-manual.pdf
Refer to chapter 7, p.29 (Electrical; pick-up coil test) page 332 of 405 pages according to the .pdf page count

View attachment 90643
Fire-medic -- going to chase your recommendation now. I just got back rebuilt carbs from Danny Unwin (nice work). now the bike will only start briefly with a fully charged battery. I can not rev it or it will die. It dies shortly anyway and the battery is draining. after it runs for a few seconds and dies, It will not restart. the battery voltage drops (last time to 11.7v), engine will turn over but not start. starter will quickly start rattling but not start. so Im back to suspecting the charging system WAS failing but is now completely kaput and the engine is trying to run off of battery alone and can't do it for more than several seconds.
 
Battery fine and it would still crank via starter, but would not start up.
As mentioned in my post, I suspect your pick-up coil is going 'open,' i.e., no continuity from the pick up coil to the ignition box. Let it cool enough, and it will start. Carry a vlotmeter with you, read the ignition pick-up coil according to the service manual, and I expect you will find it's an open circuit: no continuity one hot.

Read the service manual to test your charging circuit, the R/R does go bad from time to time, if you find yours is bad, replace it with one of these from Eastern Beaver. Note it's a Yamaha part.

https://dn790009.ca.archive.org/0/i...ice-manual/yamahavmaxvmx12-service-manual.pdf
https://www.easternbeaver.com/Main/Elec__Products/Connectors/R-R_Connectors/r-r_connectors.html
1696729854018.png
 
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any reason to suspect the fuel pump in your mind.
If there is fuel in the float bowls AFTER it has died then probably not.
However, the only way to confirm this would be to see what is coming out of the pump.

At 11.7 v the battery can be considered dead. What is the starting voltage?
To check the charging system work through the attached.
 

Attachments

  • Charging system fault_finding flow chart.pdf
    4.7 MB
Fire-medic -- going to chase your recommendation now. I just got back rebuilt carbs from Danny Unwin (nice work). now the bike will only start briefly with a fully charged battery. I can not rev it or it will die. It dies shortly anyway and the battery is draining. after it runs for a few seconds and dies, It will not restart. the battery voltage drops (last time to 11.7v), engine will turn over but not start. starter will quickly start rattling but not start. so Im back to suspecting the charging system WAS failing but is now completely kaput and the engine is trying to run off of battery alone and can't do it for more than several seconds.
fire-medic -- Thank you. I checked the pickup when it was cold (room temp) and fully charged batt (showing >13v and just off a noco genius5 charger). showed 101ohms (clymers says anything between 80 and 120 ohms is good). I got one good fire and then just cranking. voltage dropped to 11.7v. resistance on pickup was still 101 ohms. I pulled #1 plug and checked for spark grounding against engine, get consistent blue spark. gonna take a gander and what Max midnight sent.
 
If there is fuel in the float bowls AFTER it has died then probably not.
However, the only way to confirm this would be to see what is coming out of the pump.

At 11.7 v the battery can be considered dead. What is the starting voltage?
To check the charging system work through the attached.
Mr Maxmidnight -- thankyou. Im going to have to dig out the carbs so I can check the fuel flow out of the pump.

I appreciate the electrical trouble shoot guide. problem is I can't get the bike to start. so can't use it. tonight the battery was right off a noco genius5 charger. I ran battery repair yesterday. Starting voltage tonight was over 13v. I got one good pop and then just cranking. voltage quickly declined to 11.7v. I checked to resistance on pickup and it is 101ohms (good). I previously checked the R/R and the stator per clymer manual and they checked out good. I have older R/R so I can forward biase all the diodes to check it. after the failure to start tonight I pulled #1 plug and checked spark. I get consistent blue spark as it tries to crank.

so ... I have fire, I have compression (I checked), just had Danny rebuild the carbs and they ran fine on his test rig. so Im thinking fuel. ill pull the airbox and see if Im getting fuel to the carbs. I did note in the past if I cranked and cranked an engine, I usually would smell gas. my nose is not what it used to be, but Im not smelling gas in the garage. I can smell creosote on my pants from working with railroad sleepers today, so I would think I could smell gas in a garage.

open to other thoughts :-(

Update 2 hrs later -- it was the fuel pump (old one was dead dead dead)-- swapped with other bike and all is good -- started right up. now I need to replace the one I scavenged -- any recommendations? OEM from Partszilla looks like $165.
 
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From your symptoms, and since the pick-up resistance was still in-range, I'm suspecting the ignition box. Sean has a traveling kit of electrical components, you replace 1 thing at a time until you find what fixes it. [email protected]
 
From your symptoms, and since the pick-up resistance was still in-range, I'm suspecting the ignition box. Sean has a traveling kit of electrical components, you replace 1 thing at a time until you find what fixes it. [email protected]
Firemedic -- thanks for the help -- milk and cookies kept me up, it was the fuel pump. Old pump was dead dead dead. was probably only trying to start on residual fumes from when Danny had the carbs on his test bench. swapped with pump from another vmax and it started right up and ran fine.

so now I have to replace the fuel pump I scavenged from the other bike -- any recommendations -- OEM mitsubishi looks like it runs abt $165 at partszilla.
 
Hey all -- still working on getting a new to me bike ride-able -- thought I had it were I could ride to work -- but it died at highway speed and left me stranded. left me stranded. Tow truck to house.

Problem: recent past it rides fine at lower speeds -- at highway speeds it starts to cut out, feels like a surge but more likely the enginer was just cutting out. worked on it over the weekend and thought it was better. rode to work and still felt the cutting out at 65-80MPH and associated RPM. uncomfortable but still functioning. then on ride home, Hot humid day, It started cutting out and then just fully cut out, had to coast off Highway. got it going on service road and tried to ride home slow on back roads since below 45 it has been fine, but then the engine cut out again and left me stranded. Battery fine and it would still crank via starter, but would not start up. let it cool some, but still would not start. tow truck got me home, once in the garage it started up pretty easy, and will start now. Im at a bit of a loss. Hope someone can say, "yep, seen this and your problem is this"

2002 vmax
- battery is charging 13.5 V (not great but the battery is still turning the engine over). Battery never died through the whole stranding -- I kept trying to start for 1.5 hrs while waiting for tow truck. Starter kept turning over engine but no fire, engine just turned but no vroommm, then started the bike once off the tow truck. I did try choke on and off several times as the bike cooled.
- temp was good the whole time
- when by the road, I didn't ever hear the Fan (???) --- but temp was showing moderate, a little above midpoint.
- checked stator and shunt R/R last weekend -- they are fine
- RR run straight to pos terminal. crimp removed, cleaned all contacts and applied elec grease to all connectors between stator and battery and cleaned ground connections.
- new speak plugs. plug wired appear in good shape --- descent spark on the plugs
- good fuel
- synced carbs last weekend -- seemed better but then problem started creeping back in and got progressively worse.
- new fuel filter -- cut old one open and did not find rust.
- compression good -- checked last week before I changed plugs
- Air filter is clean
- RPM does not seem to matter -- can rev up at lower speeds in lower gear and seems to have no issue -- when its not completely cut out.
- thinking back, seems that it cuts out when I release the throttle or slow down if Im going at any kind of speed. i.e., going fast, let off the throttle, and engine seems to cut out, and takes a moment to start pushing again. Perhaps the engine was in fact dying when I let off, but momentum of the bike "push started" it again after 2-3 seconds. dunno.

need 4 things: compression/fuel/spark/air
- compression is good
- I think spark is good -- but could not check when I was by the road.
- leaves me with fuel and Air.

suspicions:
- Fuel -- perhaps the aftermarked fuel pump -- should I get a OEM fuel pump (not cheap if current one is fine)
- Air -- have not rebuilt carbs yet or even dug down into them -- but works at lower speed up to around 55ish in any RPM
- spark- ??? reasoning thats not it, if it was one plug or coil, then other three would have started bike or kept it going -- I would have had the bike at least try to fire -- something killed the whole system -- is there something between all four coils and the battery that could go wrong.
- odd thought -- removed crimp and replaced with butt splice that has the solder in the butt connector -- when I replaced the crimp it didn't look bad. possible the butt splice connection I made was not good and I should solder in wire and shrink wrap. but to me seems unlikely given it runs ok at lower speeds.

goign to start trouble shooting -- will probably replace fuel pump just to rule that out. then open up the carbs and start poking at those. bike had mostly sat for 2 years prior to my purchase a few weeks ago. I drove it home from purchase site (5 hrs highway). was cutting out then as well, but made it all the way home.

Thanks for any solid leads. Brett
Have you checked the prop stand switch? The engine will cut if it thinks the stand is down.
 
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