Help Fuel Issue

[Ost85vmax]

So I am lost. Hope someone has some ideas. Here is what I have done and what is going on. Started about a year ago when the fuel pump was clicking every single time I turn it on. Never ever will it stop as it should. I tore the pump apart and found the diaphram out of place. I replaced it and seemed to help but not totolly as it should. I have done this 3 times now. Finally I broke down and bought a pump from Sean and installed it yesterday and it worked perfectly. It would fill the bowls as it should and then it would stop as it should. I road it to work today (20 miles) and at lunch again it was fine. Just got home and now once again its back clicking everytime again. I would assume a diaphram is out once again but havent tore into it. Its doing the same as before with another pump. I know there has been mention of pinhle leaks in the line but it worked just fine for about a day.

The ride home was much quicker as I was getting on it a bit more and much hotter of a ride if that may make any difference.

Anyone have any ideas why this keeps happening. My next quest is to tear the carbs apart but not sure what to look for.

 

[dannymax]

Maybe drain the float bowls into a glass jar....see if there's any particles drifting around in there.

Also, there could be something screwy with the floats/needles....not exactly sure what, but think it'd be worth checking them out....could start by doing a wet level check, might give an indication.

 

[Ost85vmax]

Update. Symptoms above where when bike was hot. Bike has now cooled down to about 170 and things work as normal again.

 

[Ost85vmax]

Tried again. Warmed bike up to 210 deg. Shut it off and problem is there cools down and everything is fine.

 

[SpecOps13]

Check this thread, it may help.? :confused2:
http://www.vmaxforum.net/showthread.php?t=17117&highlight=fuel+pump+running

 

[Ost85vmax]

Wow those symptoms are exactly what it seems mine doing. I can't say I have ever felt it running on less than 4 cylinders though. Also not sure what you ment by inlet, would appreciate if you could let me know what your referring to as I think I would have to give that a try.

 

[bazwell]

SpecOps13's link covers it pretty good.

My thoughts are, check the float bowls for debris as mentioned above.
Maybe change fuel filter. See how much rubbish is caught up in the old filter.
The reason is, I'm guessing that something has got stuck onto one of the little valves in the pump causing it to not seal properly when it gets hot. In that case, the pump keeps pumping because it's too inefficient to get the 3psi or so that it needs.

Or, still guessing, there is a little bit of crud stuck onto a needle/seat in one carby, which causes pressure to overflow that carby. If the carby overflows you will see fuel come out of one of the 4 hoses that is fastened to the airbox lid (2 on each side of airbox). They are breathers for the carby float bowls, but when the carby overflows, thats where it usually comes out of.

Hope that helps!

 

[tugla]

Along with looking for crud in bowls and filters,takin a peak in the tank might reveal issues adding to the problem from rust....

 

[Ost85vmax]

It's going to be a few days but I will look into all of these and report the results.

 

[SpecOps13]

Wow those symptoms are exactly what it seems mine doing. I can't say I have ever felt it running on less than 4 cylinders though. Also not sure what you ment by inlet, would appreciate if you could let me know what your referring to as I think I would have to give that a try.

This:
I was out riding tonight and after the bike was warmed up, it started to run on 3 cylinders.
Had some trash in carb 2, holding the inlet open and overflowing that carb. Cleared that, tested
the Plugs, Fired right up on 4 cylinders... Pump was then acting like it's supposed to, again...

I meant that the carb had trash (Rust Particles) holding the Needle and Seat open at the inlet of the #2 carb. Once I flushed that out by opening the carb drain screw and letting the pump run to force gas through, it cleared up the problem. These carbs can be a RPITA if they are not clean and kept that way.

As far as gas overflowing, it's happened to me several times and could have been very dangerous as it ends up running down onto a hot engine and pipes. Now that I've gotten the carbs and fuel system to a state that it stays clean they work well. I still drain the carbs about once a month into a white paper cup just to insure that all is well. The rust particles are easily seen in a white cup. I flush any affected carb several times if I see any garbage in it. Also, I don't run Ethanol, Ever. Real gas doesn't cost that much more when you consider the better gas mileage.

Good Luck.....

 

[SpecOps13]

Oops, Double Tap Obviously.:bang head:

 

[m-cman]

This:
I was out riding tonight and after the bike was warmed up, it started to run on 3 cylinders.
Had some trash in carb 2, holding the inlet open and overflowing that carb. Cleared that, tested
the Plugs, Fired right up on 4 cylinders... Pump was then acting like it's supposed to, again...

I meant that the carb had trash (Rust Particles) holding the Needle and Seat open at the inlet of the #2 carb. Once I flushed that out by opening the carb drain screw and letting the pump run to force gas through, it cleared up the problem. These carbs can be a RPITA if they are not clean and kept that way.

As far as gas overflowing, it's happened to me several times and could have been very dangerous as it ends up running down onto a hot engine and pipes. Now that I've gotten the carbs and fuel system to a state that it stays clean they work well. I still drain the carbs about once a month into a white paper cup just to insure that all is well. The rust particles are easily seen in a white cup. I flush any affected carb several times if I see any garbage in it. Also, I don't run Ethanol, Ever. Real gas doesn't cost that much more when you consider the better gas mileage.

Good Luck.....

+1 It seems that 90% of the problems this bike has are carb related. Ethanol has just made them much worse. Unfortunately, ethanol-free gas in not available anywhere near where I live. The only thing I have found that helps, especially if the bike sits a lot, is StarTron. I use that and SeaFoam all the time unless on a trip where fresh gas is constantly being run thru the carbs. The StarTron especially helps when sitting for long periods of time. SeaFoam just helps keep the carbs clean. There are 7 gen 1 Maxes in my riding group and I have completely gone thru the carbs on 5 of them. Some of them more than once. Could do it in my sleep almost now. :biglaugh:

 

[naughtyG]

It's going to be a few days but I will look into all of these and report the results.

Just so you know my 2000 bike has a similar problem - the pump always clicks a lot (20+ times) when I switch on, even if I've only just ridden it a little earlier. I also get exhaust popping at times, and I've found that one of my lower rubber boots (between carbs and vboost assembly) is broken so is prolly letting air through. I think that's my problem.

So going to yours - could it be that you have a similar thing, and that when it's hot and the rubber softens the leak appears?

 

[Ost85vmax]

All brand new rubber a year ago. New pump. Strange things is I just ran some seafoam through it and tonight after getting home and the bike is hot all is good. Next time it happens I am going to tear into it and clamp the fuel line where it attaches to the carbs and see if it builds pressure. That will determine if indeed its the carbs or something prior.

 

[Ost85vmax]

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