Fuel problem

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yukonerdave

Well-Known Member
Joined
Jun 28, 2009
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Location
Lafayette IN
Hello all

I didn't see an intro page, but this is my first post as a new member. I am a VERY proud owner of a new (to me) '85 max. Been looking at these bikes for 4/5 years now and I finally found one I could afford! Couldn't be happier with it.

Anyway, thanks a lot for the explanation of the reserve system. I have a somewhat odd issue that I'd like to ask about. I scanned through the posts and I don't believe this one has been addressed, but please forgive me if I've missed it.

I picked up the bike about 100 miles from my home. The charging system was failing, and the battery was almost drained, but it would just manage to start still. I filled the tank and rode it home, then charged the battery. I then rode around a little more and the low fuel light came on at about 110 miles. I switched to RES and filled up after another 5 miles or so (I now gather that the tank must have been pretty damn empty at that point!). Anyway, the bike didn't sputter or hesitate at any point so I guess I lucked out. After filling the tank, I switched back to ON. Next day I ride the bike out to my mechanic to have the charging system looked at (turns out that it was simply some poor connections and has since been fixed). About 10 miles in, the bike dies on the highway. It sits for 3 or 4 minutes, I try to restart, and eventually switch back to RES. This seems to work, and I ride with no problems another 10 miles to the mechanic. During the ride I switch it back to ON. Mechanic says that he has it die on him as well, and that switching back to RES seemed to solve the issue. He assumes that the tank is nearly empty, but recall that it is only down a gallon or so at this point. Anyway, the charging system is fixed and I ride 5 miles to a gas station and top it up (takes less than a gallon). Another 5 miles down the highway and it dies on me. I fiddle with the switch, start and go 4 or 5 times and eventually it starts running strong again. I now have the switch in the ON position and I've put 40 miles on it with no more problems. One more thing: when I start the bike the fuel light does NOT come on. The manual says that this suggests an electrical problem of some sort.

At first I thought that with the charging system failing the fuel pump was not getting enough power, but now it looks more like a problem with the fuel switch. Should I still be worrying about the fuel pump itself? Any suggestions on how to troubleshoot the issue? Should I just make sure to fill up before 90 miles and hope that I don't have the issue anymore? I'd like to be able to take off down some back country roads without worrying about it dying out unexpectedly again.

Thanks a lot
 
Re: The V-max fuel reserve (guage) explained.

others would know if that points to an electrical problem (not having a fuel light go on when starting) i dont' remember off hand esp for an 85, but u may want to also just clean out the switch a bit. take it apart and clean out the contacts n such (the handlebar switch) Its possible it was shutting off the fuel pump when u kept flipping it back n forth and now it finally ground out the filth and is making connections?
 
Re: The V-max fuel reserve (guage) explained.

That makes sense and cleaning it out sounds like the right place to start anyway. Thanks for your thoughts
 
Re: The V-max fuel reserve (guage) explained.

So I took the switch apart and cleaned it. I've put well over 100 miles on it in various conditions (some putzing around town, some almost-shit-my-pants open throttle rides on some back country roads) with no problems. I rode to about 90 miles, filled up the tank before the light came on, and then put another 50 miles on with no prob. Just today it sputters and dies while I ride casually to work (trip is at 54). I switch to RES and start/stop for about 5 minutes before it starts running clean again. Weird. Any other ideas?

But connection? or faulty relay? dirty switch contacts? bad ground contact to fuel guage?
 
Re: The V-max fuel reserve (guage) explained.

I posted you prob. on the vmoa web site and this is what I got so far


Sounds like the fuel pump is ok if when you swtch to RES-ON the bike runs again. (RES-ON use the same fuel pump just a bypass circuit dor low fuel sensor)Is the red fuel light comming on early and/or when you have to switch over? if not maybe the fuel pump relay /circuit is failing.

If I get any more I'll post them
 
Re: The V-max fuel reserve (guage) explained.

Thanks Bones

The red light does not come before it sputters, and I know there is plenty of fuel left. The only time I've seen it come on is when I had well over 100 miles on it and it was supposed to come on. It does not flash on when I start the bike (like the oil light), and I gather that it is supposed to.

Do you have to be a member of VMOA to use the forum there? Are most people here members?

Thanks again
 
HaHa

So I'm a retard. Figured that there were too many possible problems that fit my symptoms so I brought it in to my mechanic today. He tested everything and couldn't find anything wrong, and then realized that the venting hose was pinched off in the battery case. I guess when I removed the battery to have it tested I pinched the venting hose off when I put it back in. He thought that this could explain the issue I've been having with it. Ah well - he also tuned the VBoost system and only charged me 20 bucks.
 
I filled the tank and rode it home, then charged the battery. I then rode around a little more and the low fuel light came on at about 110 miles. I switched to RES and filled up after another 5 miles or so (I now gather that the tank must have been pretty damn empty at that point!). Anyway, the bike didn't sputter or hesitate at any point so I guess I lucked out. After filling the tank, I switched back to ON.

The reserve switch is kinda labeled funny. "RES" is actually the normal running position and "ON" means your in reserve.
 
The reserve switch is kinda labeled funny. "RES" is actually the normal running position and "ON" means your in reserve.


i disagree
 

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LOL I was just about to tell you to check your vent tube and then I read down...

Damn... I wanted to be the hero here...

It happens more than you think...

Chris
 
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