Fuel related questions: 95m900

[erkishhorde]

Boo, I was hoping that the disconnected hose was screwing up the fuel/air mixture and causing the fuel pump to work too hard and thus overheat and stop working.

Also, if you can just bypass the fuel pump and let it gravity feed, why is there a fuel pump there in the first place?

[ducpainter]

Boo, I was hoping that the disconnected hose was screwing up the fuel/air mixture and causing the fuel pump to work too hard and thus overheat and stop working.

Also, if you can just bypass the fuel pump and let it gravity feed, why is there a fuel pump there in the first place?

The outlet is too low to get all the fuel from the tank.

[erkishhorde]

The outlet is too low to get all the fuel from the tank.

Lol, so now I've got the fuel capacity of a new bike. 

Got the bike together sans fuel pump. It SEEMS to run fine. Didn't get to do a thorough run down but it ran very smoothly on the 55mi trip from my parent's place to my apt. Complained ever so slightly when I tried to pass a car on a hill and I quickly gave up since I didn't want to push it at all in the dark. I'll give it a good run tomorrow.

[erkishhorde]

CLOSURE!!!

For make the beast with two backs's sake! I finally got it licked I think!

Bypassing the fuel pump didn't totally solve my problem. I still had problems but they didn't seem as bad. I'll tell you why in a second.

After thinking that it was rust, I had a POR15 treatment done on my tank. My guy said that he didn't find anything unusual. No large scales of rust or anything of the sort. Bugger, oh well, at least now I won't have to deal with that in future.

Then when I got the bike back from the POR15 I got really frustrated because the bike wouldn't start! WTF! Well, when I was doing all my fuel pump fiddling I had replaced half of the fuel lines, all the lines from my petcock to the carbs. I figured now was as good of a time as any to do the rest, everything from the tank to the petcock. Still no joy.  Clean the carbs? make the beast with two backs! 6 O-rings and 2 gaskets for a carb cleaning cost $41!  Still no joy. 

Dad pops in and goes, "Well, get a dropper and put some gas down the carbs and then see if the bike starts. Nick had mentioned something similar but it totally slipped my mind since I was already dead set on cleaning the carbs. Well, it worked. The bike started and then died. Fuel starvation... WTF??? I've already done everything...

Oh wait... When I took off the fuel line going to the carbs a little filter came off the carbs with it... Hmm... that filter didn't look dirty but I hadn't really thought of it and hadn't looked at it closely so I decided to take another look. Oh look, there's a crapload of black stuff! What is it...? Kinda looks like... rubber? Hose? OOOOOHH!!! The original problem may have been fuel pump issues waaaay back at the beginning but because my fuel lines were so old, when I started bending them around to do the fuel pump and the POR15 it caused the brittle lines to flake off on the inside! These flakes then clogged up the little filter at the carbs! I never saw it because the bike always sat before I took it apart so the fuel would drain a bit and take all of the little rubber bits back down the fuel line where I never saw them. Bypassing the fuel pump sort of helped my problem because the gravity feed wasn't strong enough to carry enough of the rubber flakes to totally clog up the filter. Why these problems only seemed to pop up when I was very low on gas, I have no clue.

So, I drained all the lines into a jar with a paper towel over the top to get the rest of the rubber shavings out and try to save the fuel. A quick test ride and the bike runs fine! Well, it's idling a little low and kinda dies but it could just not have warmed up yet. I'll give it a beating tomorrow and try to run it through at least one or two tanks of gas to see if I've got the problem fully licked. I can now pull the airbox off my bike in about 3 minutes and put it back on in about 5.  Funny how the first time took me nearly half an hour to get it back on.

Thank you to all that helped. CASE CLOSED! I hope...    [moto]

[dlearl476]

I also found that my vent hose for the tank got disconnected some how but I don't think that matters. The hose was surprisingly hot though considering that it was just sitting there not attached to anything. Must have been heat transfer from the frame.


It seems to be only occurring when the bike is hot. I think it just seemed to be related to fuel level at first due to the distances that I ride and the spacing of my breaks.

Take something and attach it to the vent hole and blow into it.  If you can't without resisitance, your vent is clogged.  IMO, your bike has the exact symptoms of a clogged fuel vent.

Stangman mentioned carbs and jetting. How would the carbs be causing this issue?

How many miles are on your bike?  Over time, the needle running in the emulsion jet can wear and become oval, which lets in extra air around the needle and messes with the mixture.

[greenmonster]

Congrats on faultfinding!

I can now pull the airbox off my bike in about 3 minutes and put it back on in about 5.

I don`t belive you.
After 50 efforts, my best was 8,20 minutes.

Start: Bike assembled & runnin. All needed tools on bench.
Finish: Airbox on bench.

[dlearl476]

CLOSURE!!!

For make the beast with two backs's sake! I finally got it licked I think!


Thank you to all that helped. CASE CLOSED! I hope...    [moto]

Congratulations. As much trouble as you went through, IMO you found out the "easy way" your fuel lines were crap.  Mine, I split the line that comes out of the tank to the filter and dripped 3 gal of gas in my garage while I was at work.  It's a miracle my water heater pilot light didn't blow up my freakin' garage.   

NOTE TO OLDER MONSTER OWNERS:  Your fuel lines are more than likely crap. Replace them before the screw you over.