Fuel pump

[yukonerdave]

Hello

So I've posted on this problem in some different treads and I thought I had it figured out, but I have one more question. EVERY time I switch the bike on the fuel pump clicks for at least 5 seconds. I can turn it on, let the fuel pump run, turn it off and immediately turn it on again and the pump will run again for a full five seconds. I understand that the pump should only come on when the bowls are empty, and only enough to fill them. I had some clear tube on the pump and it is not actually pumping fuel into the carbs every time (i.e. it is not overfilling them), but it does click for that long. Also, my fuel light does not come on when I start the bike. The oil light does, and I know the fuel light does work because it came on last night when I hit about 92 miles.

I was having an issue where the bike would sputter out and die when I knew there was plenty of fuel left, but that problem seems to have been a pinch in the vent hose (it has not happened since the pinched hose was fixed). So the fuel delivery system as a whole seems to be functioning fine; I just don't understand why the light doesn't come on when I start it, or why the pump always clicks when I turn the machine on.

I have a VERY basic multimeter, but I can't test ohms or anything like that. Does thins sound like something I need to take in to a shop?

THANKS

 

[naughtyG]

I'm not 100% on this, but I would check out the fuel pump relay.

Have you got a good manual like Haynes, or downloaded the Yamaha service manual from vmaxoutlaw.com?
The Yam one has all the service procedures for things like this, although it does assume some previous mechanical knowledge..

 

[maleko89]

I would remove the fuel pump and make sure there aren't any tears/holes in the rubber diaphragm. If the fuel pump clicks and fuel isn't coming out then the problem is somewhere between the fuel tank and fuel pump. I had the same problem where once in awhile the fuel pump would click like crazy. I had a pin hole in one diaphragm so put some Ultra Black on it and it hasn't done it since.

 

[one2dmax]

The electrical is working fine. It's not building pressure so it can shut off. It can either be the diaphrams as noted eariler or it can even be a hole/sealing problem with the hose/filter prior to the pump. This allows air to be pulled in and not fuel.

I just fixed one doing this last weekend. I took the pump apart and cleaned it all up and put it back together. The area to look at is the 2 small dime sized rubber diaphrams in the pump.

Sean Morley

 

[yukonerdave]

Awesome - thanks for the tips. I will plan to check the pump thoroughly in the next day or two. I'll let you know what I find.

 

[jfeagins]

I've had this on both my Vmax's and it ended up being the tiny rubber seal slipped out of the spring loaded bracket at the inlet side of the pump. There are two of these tiny one-way 'valves' - one each side of the pump. If that little rubber gets out of the bracket, it is letting the pressure return to the fuel tank. I pop it back in with a small screwdriver tip, being careful not to damage it. Don't know how it gets out to begin with.

 

[yukonerdave]

Re: Fuel pump BIG THANK YOU!!!

Ok, BIG kudos to Maleko89 who first suggested the diaphragms and to one2dmax who concurred. And a HUGE thank you to jfeagins who hit the nail on the head with the cause of my problems - a misplaced diaphragm.

Seriously, without your tips I would have just replaced the whole pump - as it is, I eased the diaphragm back into place and the problem is now solved. For the first time I am able to clearly hear the vboost servo whizzing before startup. If I ever meet any of you guys, remind me that I owe you a beer.

I took pics of the whole process and will post a walkthrough in the "How-To" section.

Thanks again

 

[gamorg02]

Re: Fuel pump BIG THANK YOU!!!

Ok, BIG kudos to Maleko89 who first suggested the diaphragms and to one2dmax who concurred. And a HUGE thank you to jfeagins who hit the nail on the head with the cause of my problems - a misplaced diaphragm.

Seriously, without your tips I would have just replaced the whole pump - as it is, I eased the diaphragm back into place and the problem is now solved. For the first time I am able to clearly hear the vboost servo whizzing before startup. If I ever meet any of you guys, remind me that I owe you a beer.

I took pics of the whole process and will post a walkthrough in the "How-To" section.

Thanks again

awesome its solved. i think its great u did that, we need as many walkthrus as possible. it will probably save a few headaches down the road as well. can't wait to see it written up.

 

[cheredstar01]

ok guys. sorry if this one sounds wacked but i had a similar problem on my 85 max. took the pump off and sure enough the diaphragm was out of place. everything back together and now after 5 seconds of running my fuel light comes on and does not go off. also does not seem to get as much fuel. no kinks in the line and no apparent leaks. any ideas?

 

[naughtyG]

I would just take it off again and double-check you got everything back in place properly. It's easy to overlook something the first time..

 

[gamorg02]

not to be the dumbass. but u def have enough gas right?

 

[one2dmax]

it's possible that you distirbed some contaminates on got it into the pump or float bowls. You could be low on fuel. You may have a float hanging up. Try tapping on the bowls or carb bodies and see if it dislodges the dirt and lets you get back to normal.

Sean

 

[Roadracer]

This sounds exactly like the intermittent problem I'm having.

Thanks everyone!

 

[cheredstar01]

thanks naughty. will do. i have no problems with gears and such but aways feel awkward with electronic parts. also tried to find a replacement pump. wow does anyone know where to get a replacement pump and how much it might cost? I can't find one anywhere. yes. i have a full tank and shotgunned the carbs and tapped the bowls. still wacked. maybe need new pump.

 

[naughtyG]

thanks naughty. will do. i have no problems with gears and such but aways feel awkward with electronic parts. also tried to find a replacement pump. wow does anyone know where to get a replacement pump and how much it might cost? I can't find one anywhere.

You can try www.bikebandit.com

For THE best prices ever on Yamaha OEM parts though, ring Gary McCoy @ Mondak Motorsports (406 433 6635) and mention you're a Vmaxforum member, he gives us a hefty discount! :eusa_dance:

Then ring any Yamaha stealers and compare..

 

[Birdoprey]

thanks naughty. will do. i have no problems with gears and such but aways feel awkward with electronic parts. also tried to find a replacement pump. wow does anyone know where to get a replacement pump and how much it might cost? I can't find one anywhere. yes. i have a full tank and shotgunned the carbs and tapped the bowls. still wacked. maybe need new pump.

If it'll help ya any, i've got the stk pump from my 89. You can have it for free, just pay shipping.

 

[one2dmax]

that's a good price! If it doesn't work out I have a few spares I can sell you. I have only ever had to replace 2. Most of the time they need taken apart and cleaned or the diaphrams in them put back into position.

Sean

 

[cheredstar01]

wow. very cool birdoprey. thanks for all the info guys was getting very frustrated.
never had any probs with my 85 till this year. reg/rec went out and now this little problem.
this forum is definatley saving my butt. if you message me birdoprey i will get the shipping cost to you.