Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphram?

Yesterday I had something occur that I have not experienced before on my 1996 ST110 qith 79,000 miles. I was 230 miles into a ride on the same tank of fuel, gauge showed 1/4 tank left. This was all back roads at various speeds up to ~70. Outside temp was mid 70s, sky was overcast but no rain all day. About 1/2 a mile before a stop sign the bike started acting like it was running low on fuel, then maybe running on two cylinders. As I pulled in clutch to stop it quit running. I tried to restart and it spun over fine and tried to catch but didn't. I loosened the gas cap, put it back on and it started after a couple of tries. I then rode another 30 miles and it happened again. Loosened cap, replaced it and started again. Rode the 20 miles left to home and parked it. I had something similar happen in June coming back from Colorado but I smelled gas that time and I had to bypass the vacuum operated fuel shutoff valve. I rebuilt it when arriving home to Fl and it's been fine. So, is vapor lock a myth or possible? When I removed the cap I don't know if it was under pressure or vacuum. I'm thinking it may just be a faulty gas cap but I'm open to suggestions. Thoughts?

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

sounds like the hot fuel pump syndrome. Has the fuel pump been changed??

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Al st1100 said:

sounds like the hot fuel pump syndrome. Has the fuel pump been changed??

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It has not been changed. I would think if it was hot though it would have taken some time to cool off. It restarted immediately.


Ashley

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Any one have experience with these? http://www.highflowfuel.com/i-13868228-new-intank-fuel-pump-honda-st1100-replaces-honda-16700-mt3-010-1990-2002.html


Ashley

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

??? Glad you got home OK. Maybe we should have done SR13 after all!

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

when my fuel pump went out It acted the same way. I pulled off the fuel line (second time when would not start)and turned key on and no fuel came out. I checked fuses which took another 5min and rechecked key on fuel and suddenly fuel came out. I drove another 1300 miles ( to get home ) with out a problem . Read all the st1100 fuel pump posts and it kinda acts that way. I found when it runs out of fuel the bike tends to slow down. You can do a fuel pump for under $50.

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Has the petcock diaphragm been bypassed or removed? My Black had that happen , and it restarted then ran for some time, but then I flipped things around to remove the fuel stopping portion.
It was tooling along happily and then acted like it ran out of gas, but it had a near full tank.
Upon opening, the diaphragm had a hole in it, at lower loads the motor had enough vacuum to keep it open, so once it restarted I was able to get down the road to a lighted place to remove tupperware and fix the issue (this happened to me at 11pm, between Hope and Benton Ar). I later bought a replacement diaphragm, but they don't fit well, so it just got used to seal things, and is still bypassed ... flipped things to seal the vacuum hole
Both my 91s have well over 90,000 miles and the stock pumps are still going (and now I've jinxed myself, haven't I?)

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

http://www.ebay.com/itm/255LPH-High-Pressure-High-Flow-Fuel-Pump-In-Tank-Install-Kit-Fits-GSS341-/400607093122?fits=Year:1993|Make:Honda|Model:Prelude&hash=item5d460b2182:g:EPkAAOxyOeBR5Dss&vxp=mtr same pump is all over ebay from 20 to 120 dollars There are 15 pages of st pump replacements but find the 2 or 3 posts that use the fuel pressure regulator from the oe pump

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

dduelin said:

??? Glad you got home OK. Maybe we should have done SR13 after all!

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As soon as I left you it started acting up. Almost called you but it started back up.


Ashley

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

JPKalishek said:

Has the petcock diaphragm been bypassed or removed? My Black had that happen , and it restarted then ran for some time, but then I flipped things around to remove the fuel stopping portion.
It was tooling along happily and then acted like it ran out of gas, but it had a near full tank.
Upon opening, the diaphragm had a hole in it, at lower loads the motor had enough vacuum to keep it open, so once it restarted I was able to get down the road to a lighted place to remove tupperware and fix the issue (this happened to me at 11pm, between Hope and Benton Ar). I later bought a replacement diaphragm, but they don't fit well, so it just got used to seal things, and is still bypassed ... flipped things to seal the vacuum hole
Both my 91s have well over 90,000 miles and the stock pumps are still going (and now I've jinxed myself, haven't I?)

Click to expand...

Rebuilt vacuum petcock in June.


Ashley

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

First thing would be to remove the cutoff even though it was just rebuilt to eliminate it as a cause. My hunch is either carb icing or fuel pump failure. Mine exhibited the same symptoms several times before I finally replaced them. They would recover and work fine for a while, then do it again. Low fuel level and temps that are up can really bring it on. I have a little 'backup' pump that I can put in place if need be that I carry with me on long trips.

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Thanks all. Think I will bypass fuel cutoff for next ride and see what happens.


Ashley

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

by passing the the fuel petcock is a good starting point. after that, keep track of the fuel levels. when my own f.p. died, it would work when the tank was over half filled and die when it went below half.( my own petcock has been in bypass for over 5 years now- well before my pump died)

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Ashley,

Very glad you made it home okay.
My '01 still has the vacuum petcock still fitted, and the '91 has the bypass done by a PO. The only difference I notice between the two is that if the '91 gets ridden for a while, getting a good heat soak, there will be a moaning sound periodically from the tank, to equalize pressure, for up to 20 mins after stopping.

I'd recommend putting a temporary bypass in place, see if it starts and runs okay, if it does take it for a good run (covering miles, without ever going too far from home, just in case). If there's no issues, chances are it's the petcock. If there is, chances are it's the pump.
If it's the petcock, then it's your choice to repair, replace, or bypass.

Good luck with it.

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Fatjock said:

...if the '91 gets ridden for a while, getting a good heat soak, there will be a moaning sound periodically from the tank, to equalize pressure...

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Both my STs, the '94 and '00 emit the "tank vent moan" when the conditions are accordingly...

I'd recommend putting a temporary bypass in place, see if it starts and runs okay, if it does take it for a good run...

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I check the fuel valve as follows:
- look if dust has accumulated around the breather hole at the bottom of the valve body
- disconnect its vacuum line, attach a piece of hose at the stub instead, put the other end between your lips, draw vacuum and plug the hose with the tip of your tongue; if it holds the diaphragm is OK, if it leaks a rebuild kit is due.

The diaphragm can have a small rupture without causing fuel problems... the carb sync @ #3 would be off though...

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Uncle Phil said:

First thing would be to remove the cutoff even though it was just rebuilt to eliminate it as a cause. My hunch is either carb icing or fuel pump failure. Mine exhibited the same symptoms several times before I finally replaced them. They would recover and work fine for a while, then do it again. Low fuel level and temps that are up can really bring it on. I have a little 'backup' pump that I can put in place if need be that I carry with me on long trips.

Click to expand...

Curious about your backup pump..

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

I picked up a low volume one at a NAPA auto parts in nowhere Idaho when I encountered my first fuel pump problem. It's already got fuel line and clamps on each end and wiring attached so I can connect it to my fuse block which is only on when the key is on. I don't even remember the model number or brand, but it worked. So I keep it in a little 'tote' bag that I throw in my left saddlebag whenever I take non-local trips. To install it, I just disconnect one end of the fuel filter, put the pump in line, tighten the clamps, run the wire to my fuse block in the tailpiece and be good to go in short order. I removed the fuel cutoffs along time ago on all my ST1100s.

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Uncle Phil said:

I picked up a low volume one at a NAPA auto parts in nowhere Idaho when I encountered my first fuel pump problem. It's already got fuel line and clamps on each end and wiring attached so I can connect it to my fuse block which is only on when the key is on. I don't even remember the model number or brand, but it worked. So I keep it in a little 'tote' bag that I throw in my left saddlebag whenever I take non-local trips. To install it, I just disconnect one end of the fuel filter, put the pump in line, tighten the clamps, run the wire to my fuse block in the tailpiece and be good to go in short order. I removed the fuel cutoffs along time ago on all my ST1100s.

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since the fuel tank has pressure in it, What would stop the fuel from coming out if you have a fall or tip over (lets say that the engine is not running) since the floats in the carb would not be working? And how much fuel could come out??

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Al st1100 said:

since the fuel tank has pressure in it, What would stop the fuel from coming out if you have a fall or tip over (lets say that the engine is not running) since the floats in the carb would not be working? And how much fuel could come out??

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I reckon if I have a fall or a tip over, I figure I have more pressing things to worry about than the gas that might end up on the ground. That usually come with at least $600 worth of bodywork - mirror, cover, saddlebag lid and tip over wing ... not to mention the harm to the human bodywork ;-) If I'm stopped on the side of the road in the middle of nowhere or on the side of the interstate because of a fuel pump 'fail' (and I have been), this setup can get me to a safer place that I can better deal with it instead of trying to get a cell signal or abandoning the bike to walk to help. This is for 'temporary' side of the road fix, not a permanent replacement. There are places in BC, the Yukon and Alaska that if you sit too long on the road side, you can become bear bait and it can also be a really long time before anybody comes along.

Re: Bike started running poorly then quit and restarted. Fuel cap? Fuel Pump? Diaphra

Al st1100 said:

since the fuel tank has pressure in it, What would stop the fuel from coming out if you have a fall or tip over (lets say that the engine is not running) since the floats in the carb would not be working? And how much fuel could come out??

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That's the purpose of the vacuum fuel valve. Tip sensor kills the engine which kills the vacuum required to keep the fuel valve open.


-Jeff