gas problem.. for sure

[soon2briding]

ok.. so i asked the question a week ago about what to leave the gas setting position on... i said that i found that i left mine on PRI ... but then i foudn out it is supposed to be on ON... so i changed it... and while i was riding this week.. i only had used up about 60 miles of gas... so i still had a good amount of gas left... but then my bike started to sputter... loss of power... and the bike just shut off on me... i try to start it up... and it wont start up... so i put the gas to RES.. still doesnt start up... i put it into PRI wait about a minute and  it starts up with ease... i bet someone already posted this.. but can somebody help me? what problem do i have... what can i do to fix it or find out more specifically what the problem is... any help is appreciated...

[rhenter]

fill it up with gas.  Make sure you fill it up all  the way.  When the gas pump shuts  off the first time, you should be able to get close to another gallon of gas in it.  My guess is that you only got 60 miles till reserve because you didn't  fill the tank all the way.  I fill it up to the neck and shake the bike a little and keep topping it off.

[The Buddha]

OK vacuum line is blocked or has a hole or is missing. Carbs to the back most... closest to the airbox line in the petcock.
Cool.
Srinath.

[Kerry]

what can i do to fix it or find out more specifically what the problem is...

Time to "experiment"!  Or maybe "practice" would be a better word.  "The more you know, the better it gets!", right?  

Here's what I would do.  (This assumes that you haven't refilled your fuel tank since you posted.)

1) Sit on your bike with your left foot on the peg and get a feel for where the ON/RES/PRI petcock is.  I find that putting the back of my hand against the inside top edge of my boot gets me really close.

2) Put the petcock in the PRI position (up on an '89-'00 bike), and go for a several-mile ride.

3) On a long, relatively traffic-free straightaway, switch the petcock to ON (down on an '89-'00 bike).

4) Hopefully the bike will start sputtering, etc.  As soon as it does, reach down and switch the petcock to RES (forward on an '89-'00 bike).

5) The bike should sputter 2-5 more times and then "pick up" again.

-------------------------------------

6) If the bike doesn't "pick up" then either reach down and switch the petcock to PRIme or pull over and do it.

7) Get thee to a gas station!

-------------------------------------

What makes this tricky is not knowing the fuel level in your tank.  I'm assuming that it's between the ON and RES levels, but I could be wrong.  This is how it should work, anyway.  I'm thinking that RES didn't work for you before because you're weren't able to switch to RES fast enough, and the vacuum suction (on RES) doesn't work as quickly as the gravity feed (on PRI) does.

One more observation.  Several times I have been forced to switch from ON to RES (Step 4 above) many miles before I should have needed to.  After the bike smoothed out again, I switched back to ON and went several miles before the sputtering started again.  This has usually happened at freeway speeds, when the engine is "guzzling" the gas.

Moral: Try try again - enough times so that you know what to expect and can react quickly.

[soon2briding]

could it be a gas problem?... before i put the gas setting on ON i had it on PRI and i went at least 100 miles before i needed to fill up.. just for safety reasons.. not because i was sputtering... and i looked at the tank.. it was filled with a good amount of fuel... more suggestions?.. oh yea.. and after that... i put it on PRI and i rode to the beach.. it went fine.. no problems... then i filled up... and still fine... i think maybe its something wrong with the fuel delivery..

[Kerry]

There's nothing inherently wrong with leaving the petcock on PRI.  It's almost exactly as if you didn't have a petcock in the circuit at all, but a hose straight from the fuel tank to the carbs.  The bike will run in the PRI position long after it stops running in the other positions.

I can only come up with 2 possible problems with this approach:

1) You have to watch your odometer to know when to fill up again, because the bike won't give you a "time to switch from ON to RES" warning when the level gets low.  When the fuel runs out on the PRI position - that's IT.  (Well OK, you can nurse a little more fuel through a little bit at a time, but still....)

And if your riding conditions change somehow (uphill, headwind, big change in altitude or temperature or humidity) you may run out of fuel before you normally would.  Moral:  Guess conservatively!

2) The only thing keeping the fuel from flowing in this position are the float needles in the float bowls.  When the engine is not running they plug up the hole in each carb that allows fuel through.  If you ever get sufficient rust (or other gunk) in EITHER carb to prevent the float needle from sealing up that hole, your fuel tank will empty into the airbox and/or the cylinder(s) and probably out onto the ground.


So much for the warnings.  As long as you know what to watch out for, feel free to use the PRI position.  But I still think it would be a good idea to know how far your bike will typically go in the ON position before you need to switch to RES, and then how far before PRI is your last resort.  (And then how far before you've got NOTHING left.)

[soon2briding]

i guess ill give it a try.. but i think i've got it figured out.. because.. after i switched to the ON position i filled my tank.. and i always reset my trip meter after every fill up... so i got about 60 miles... let me try what you suggested... thanks much kerry

[Kerry]

All the more reason to make sure -- 60 miles is WAY low.  On my '99 I usually get about 170-180 miles in the ON position.  When I ran the tank next-to-DRY on my trip last year I had gone only about 130 miles in the ON position, then got about 47 miles on RES, crossing my fingers the whole way!

After switching to PRI I still had to stop on the side of the road 2 or 3 times, leaning the bike to the left for a couple minutes each time, before I made it the last 6 miles to a gas station.

"Thank You ... Belt, Montana!"

[Kerry]

For your viewing pleasure:



1) Filled up the night before, after leaving Yellowstone.
2) Turned off onto a back road to get to...
3) ...the campground we stayed at.

From I-90 to White Sulphur Springs my Dad and I rode into a slanting headwind across the plains.

4) This was the first time my bike sputtered and I switched to RES.  I switched it back to ON a mile or so later, and went uphill for awhile with no problems.
5) Coming back down the hill (70+ mph sweepers - pure joy!) I had to switch to RES for good.
6) The bike finally died and I had to switch to PRI.  After two or three stops I got to the top of the hill on US 87 and...
7) ... coasted down into Belt, where I put almost 4.4 gallons into my 4.5 gallon tank.

Whew!

As for why we didn't stop in Neihart or Monarch - don't ask.

EDIT: Changed link from sisna.com to bbburma.net.

[ejl10]

This was a recurring problem for me for about 2 years.  It was downright scary when the bike suddenly died on the highway while I was trapped between two semis...

Anyhow, I replaced most of the fuel system and rejetted thrice before I was done, and it didn't solve the problem.  However, when I replaced the stock airbox with higher flowing pod filters it seemed to go away, and hasn't happened since.  

Back a few years ago this was a really hot topic on the board... everyone seemed to be having the problem.  It doesn't come up as much anymore.  Other solutions that seemed to work for some people were rejetting, replacing the vaccum line, installing a Pingel petcock, and opening the gas cap (it wasn't venting properly).  Everyone's problem seemed to be a little bit different.

Good luck with yours, and be sure to ride safe until you've got it licked.  Stay away from those semis!
Emmett Lyman