My first Vmax, will not run.

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hairballrm

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I figure this is a fuel issue, so I'll post here.

Bought it a week ago, test ride went fine. 1990 max with 56k (should be Ca but I do not know). Owner told me that the fuel cap must be in the proper orientation or the bike will “vapor lock” and quit.

Topped the fuel off, got on the freeway to bring it home, went a couple miles, stopped running like it ran out of fuel. Ran battery dead trying to restart. Ride of shame back home on the rollback. Charged the battery and started it that night. Did laps around the block till I trusted it again.

Rode it 2 miles to work Mon- Thurs. Friday morning started fine but idle changed and bike died. Drove the car. That afternoon it would not start, popped the gas cap, fired right up. Yesterday I pull the seat and blew out the vent line through the tip-over valve. Went for a freeway test ride. Died the same way again.

I could not bring myself to call a tow truck again, not after all the Harley jokes I have been telling for years. 2.2 miles of penance pushing my Yamaha home.

I have been searching these forums for guidance without success. I downloaded the factory service manual, but am having trouble navigating it. This bike rocks……. When it runs!
 
You actually have a vent coming off of the tank, if that line is plugged, the pump will create a suction, and the carbs cant get fuel. As soon as you pop the cap (and the tell tale sign is the whooosh sound) you let air back into the tank, and gas can get back to the carbs.
 
You actually have a vent coming off of the tank, if that line is plugged, the pump will create a suction, and the carbs cant get fuel. As soon as you pop the cap (and the tell tale sign is the whooosh sound) you let air back into the tank, and gas can get back to the carbs.
That's what I was thinking the problem is too.
 
You can ride the bike with the fuel cap loose to validate the vent is the issue. It's a very small hole in the line tip. You have to pull the hose and run some wire through it to open the passage back up. This is the hose that runs from the right rear area of the tank.
 
Yeah it was a fuel issue. There comes a time when humility is the best path.

The fuel pump seemed to be running longer then it should. I pulled the fuel filter to blow it out backwards, and hmmm, no gas. Flashlight inspection of the tank level revealed a bone dry condition. Insert fuel and behold, bike runs.

Interesting details: I set the odometer when I filled/topped her off. I only went 90 miles on a very full tank. Reserve light never went on, nor did, the reserve switch get me home.

I am off now to a gas station one mile away and slight downhill back.
Thanks for the support

Rick
 
At least it was an easy fix, LOL.
And if you were riding it hard 90 miles to reserve (28 mpg) isn't bad, but 90 miles to completely empty is bad (22.5 mpg).
I get about 25-28 mpg when really cranking on my Stock Vmax and up to 38 mpg when highway riding.
 
Yeah it was a fuel issue. There comes a time when humility is the best path.

The fuel pump seemed to be running longer then it should. I pulled the fuel filter to blow it out backwards, and hmmm, no gas. Flashlight inspection of the tank level revealed a bone dry condition. Insert fuel and behold, bike runs.

Interesting details: I set the odometer when I filled/topped her off. I only went 90 miles on a very full tank. Reserve light never went on, nor did, the reserve switch get me home.

I am off now to a gas station one mile away and slight downhill back.
Thanks for the support

Rick
Was your reserve switch on? If you ran dry I would take that right control off the handlebars and clean it. There is a thread on here about it and only takes a pencil eraser to clean the contacts. Well worth it. Check fuses for reserve light.
I have a fuel pump if you need one.
 
Yep good point blaxmax, make sure the reserve switch is set to ON and not RES. ;)
 

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Yep, I have always had reserve switch set to on and had been waiting to see the reserve light.
I have a fresh can of electro-contact cleaner.
The fuel pump seems to be working fine, created nice vacuum on the supply side.
The filter is ok, but should be cheap, and golly, easy to swap!
 
Yep, I have always had reserve switch set to on and had been waiting to see the reserve light.
I have a fresh can of electro-contact cleaner.
The fuel pump seems to be working fine, created nice vacuum on the supply side.
The filter is ok, but should be cheap, and golly, easy to swap!
I run 3 inline glass filters.
If your reserve light did not light up and you ran dry in the tank then there is a problem. Check the fuse. Or the light in the gauges.
 
I would incline towards the sensor in the tank as its a low level sensor not a quantity sensor. Either that or the fuel pump relay. All of that is easily tested. Check Haynes
 
I run 3 inline glass filters.
If your reserve light did not light up and you ran dry in the tank then there is a problem. Check the fuse. Or the light in the gauges.

This and some of your previous comments would lead me to believe that the "Reserve" circuit is not functioning.
The "Res." position on the switch is simply another source of supply power to the fuel pump, to be used after the "On" supply power has been cut off, due to the tank sensor doing it's function.
The simple way to check for proper operation of the Res. circuit is to switch to this position, and start the engine, with lots of gas in the tank. If the bike dies after a few minutes, the circuit is not working.
This is why I always start and warm up my bike with the switch in the Res. position, regardless of the amount of fuel available. It serves as a system check, so that there will be no nasty surprises when the reserve is needed while on the road.
Previous threads/posts have determined that the reserve light bulb is critical to proper Res. circuit operation. If the bulb filament is broken, the circuit fails. Seems like a poor design. Maybe a British Electrical Engineer was subbing for a sick Japanese employee, during the fuel system design phase? (sorry, Maxmidnight)
In any case, the proper operation of the Reserve light (as well as the Oil light), can be checked during the pre-start checks. This is covered in the manual that came with the bike. If not the bulb, I'd look at the switch next.
Cheers!
 
This and some of your previous comments would lead me to believe that the "Reserve" circuit is not functioning.
The "Res." position on the switch is simply another source of supply power to the fuel pump, to be used after the "On" supply power has been cut off, due to the tank sensor doing it's function.
The simple way to check for proper operation of the Res. circuit is to switch to this position, and start the engine, with lots of gas in the tank. If the bike dies after a few minutes, the circuit is not working.
This is why I always start and warm up my bike with the switch in the Res. position, regardless of the amount of fuel available. It serves as a system check, so that there will be no nasty surprises when the reserve is needed while on the road.
Previous threads/posts have determined that the reserve light bulb is critical to proper Res. circuit operation. If the bulb filament is broken, the circuit fails. Seems like a poor design. Maybe a British Electrical Engineer was subbing for a sick Japanese employee, during the fuel system design phase? (sorry, Maxmidnight)
In any case, the proper operation of the Reserve light (as well as the Oil light), can be checked during the pre-start checks. This is covered in the manual that came with the bike. If not the bulb, I'd look at the switch next.
Cheers!
Miles, my reserve light works but my when I switch to reserve when it lights I get NO gas.
 
my reserve light works but my when I switch to reserve when it lights I get NO gas.


1) The reserve light comes on when you're low on fuel, so your fuel sender inside the tank is working.
2) When the light comes on, the bike starts to stumble and shuts off?? If so, the circuit is telling the pump to shut down, like it should.
3) When you flip the switch to Res, you still don't get gas. So the flipping of the switch is not over riding the pump cut out circuit and not turning the fuel pump back on.

Sounds like a corroded or faulty res switch to me.
I'm no expert but just thinking about this like a computer flowchart.
 
1) The reserve light comes on when you're low on fuel, so your fuel sender inside the tank is working.
2) When the light comes on, the bike starts to stumble and shuts off?? If so, the circuit is telling the pump to shut down, like it should.
3) When you flip the switch to Res, you still don't get gas. So the flipping of the switch is not over riding the pump cut out circuit and not turning the fuel pump back on.

Sounds like a corroded or faulty res switch to me.
I'm no expert but just thinking about this like a computer flowchart.
I took it apart and cleaned it but it didn't looked like it needed it. It has never worked on reserve.I hope I didn't hijack hairballs thread- I think he resolved his problem didn't he? And I'm trying to stay on subject.
 
'Reserve has never worked?'
That sounds like a wire isn't landed where it should be or is an open circuit of another sort, either way, frustrating. I guess as long as you have access to the gas supply in the 'reserve,' it doesn't really matter, but it's a good feeling to have it his reserve, and to know you have about 25 mies to go onto fumes.


I took it apart and cleaned it but it didn't looked like it needed it. It has never worked on reserve.
 
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