Semi-retired Posted November 13, 2015 #1 Posted November 13, 2015 Am I the only dufus on the continent who has ever turned off his gas tap....for the first time of the season, cause now it's ALMOST WINTER....then had an "Indian Summer Opportunity", only to find the damn bike won't start? Cranked that sucker over about 100 times (using good, non-starter-motor-burning bursts of no more than 15 seconds cranking at a time, mind you)....only to find that, holy crap....not only is there no gas coming from the tank (Doh....forgot about shutting the tap off)......the fuel that WAS in the float bowls must have prit-neer evaporated, cause I think it turned over about 4 times under its own power, then proceeded to drain my battery down to AA voltage doing the OTHER 96 revolutions!! If the gas in the float bowls ISN'T enough to keep her running for a minute or so, where DID/DOES all that gas go? Up in vapour? Or down into the cylinders? Turning the tap on was obviously all it needed, cause after I did, the fuel pump clicked away for about another 5 seconds, THEN she fired up like a nuclear reactor. What gives?
Flyinfool Posted November 14, 2015 #2 Posted November 14, 2015 Yes you need to turn on the gas to go for a ride......... If the engine was good and hot when it was last shut off the engine heat can evaporate most or all of the gas from the float bowls.
skydoc_17 Posted November 14, 2015 #3 Posted November 14, 2015 Hey mike, Don't feel bad, been there, done that myself! But to answer your question, inside the float bowl area of the carbs. is of course, THE FLOAT! So there really isn't much gas in the Carb. The best my bike will do with the tank turned off is to stumble one time during start up. After that, it's a dry crank from that point on. Consider yourself lucky, I have seen owners turn their gas off, and had the shaft on the gas valve wring off when they went to turn the gas back on again! I personally leave the petcock on "reserve" and use the gas gage to refill the tank. The choice is yours. Earl
Semi-retired Posted November 14, 2015 Author #4 Posted November 14, 2015 I have seen owners turn their gas off, and had the shaft on the gas valve wring off when they went to turn the gas back on again! Thanks for your kind.......but scary words of advice. And I must add, the only thing scarier than having your tap twist off in your hands is looking inside your tank in the spring (after sitting for four months) and seeing nothing.......then looking in your oil level viewing window and realizing that all your gas has drained into your crankcase BECAUSE you didn't turn the tap off for the winter. DOH. That's what happened on my old 82 GS1100 one time.......and I've been nervous about "which way to go" ever since! Like everything in life.....there's pros and cons to every approach!
garyS-NJ Posted November 14, 2015 #5 Posted November 14, 2015 I ran out of gas last week in jersey city on my way to jury duty. Found my petcock on reserve. I vaguely remember trying get to turn it by hand (just after I bought the bike this summer) and it wouldn't budge and I couldn't see it and left it alone... thought I had plenty of gas. Lucky a construction crew parted with a gallon or so to send me on
alwrmcusn Posted November 14, 2015 #6 Posted November 14, 2015 My Doofus moment(s) When I'm wearing heavier cold weather gloves, accidentally brushing the kill switch to the off position. It's especially fun when you're in the middle of a tight low speed turn like at a stop sign/red light! Having the Venture "triked" helped but it's still embarrassing and I usually have no idea that's what happened for about 10-15 seconds while my itty bitty mind races thru possible causes.
tlm Posted November 14, 2015 #7 Posted November 14, 2015 Thanks for your kind.......but scary words of advice. And I must add, the only thing scarier than having your tap twist off in your hands is looking inside your tank in the spring (after sitting for four months) and seeing nothing.......then looking in your oil level viewing window and realizing that all your gas has drained into your crankcase BECAUSE you didn't turn the tap off for the winter. DOH. That's what happened on my old 82 GS1100 one time.......and I've been nervous about "which way to go" ever since! Like everything in life.....there's pros and cons to every approach! How can the gas drain from the tank, through the carbs and into the crankcase? The fuel pump is lower than the carbs.
Flyinfool Posted November 14, 2015 #8 Posted November 14, 2015 On a 2nd gen or any other bike with the tank above the carbs, If your float valves are leaking all the gas will drain down into the crankcase. The height of the pump does not matter. All that matters is the height of the surface of the fuel in the tank and the height of the surface of the fuel in the float bowel, The higher level will drain to the lower level regardless of the heights of what is in between them. The only thing that will stop the flow is to block it off with a closed valve somewhere in the system. The valves in the float bowels are plenty to do the job IF they are in working condition. The 2 valves in the fuel pump are check valves that only allow flow from the tank to the carbs, so the pump will not help stop the leak down.
Condor Posted November 14, 2015 #9 Posted November 14, 2015 I left my '83 on reserve permanently. Didn't worry about fuel draining into the crank, however on my '99, '04, and '07 the petcock is turned to off every time since the tank is on top of the carbs. I guess I'm paranoid.....??
Semi-retired Posted November 14, 2015 Author #10 Posted November 14, 2015 On a 2nd gen or any other bike with the tank above the carbs, If your float valves are leaking all the gas will drain down into the crankcase. The height of the pump does not matter. All that matters is the height of the surface of the fuel in the tank and the height of the surface of the fuel in the float bowel, The higher level will drain to the lower level regardless of the heights of what is in between them. The only thing that will stop the flow is to block it off with a closed valve somewhere in the system. The valves in the float bowels are plenty to do the job IF they are in working condition. The 2 valves in the fuel pump are check valves that only allow flow from the tank to the carbs, so the pump will not help stop the leak down. Thanks for saving me all that ink! That's exactly what I would have said.....with maybe the inclusion of one more: GRAVITY! :-)
Semi-retired Posted November 14, 2015 Author #11 Posted November 14, 2015 My Doofus moment(s) When I'm wearing heavier cold weather gloves, accidentally brushing the kill switch to the off position. It's especially fun when you're in the middle of a tight low speed turn like at a stop sign/red light! Having the Venture "triked" helped but it's still embarrassing and I usually have no idea that's what happened for about 10-15 seconds while my itty bitty mind races thru possible causes. Yup! I'm thinking we've all had ONE version or another. (Thank god they don't come that frequently....or with big audiences most of the time!) My worst one (for viewers/bystanders) happened not long after I acquired Big Bertha and I was starting her up in a crowded coffee-shop parking lot (Timmy's near the Blackberry offices in Waterloo, for all you Canucks reading this....so you KNOW the place was crawling with engineers enjoying their large, double-doubles in the parking lot on this nice sunny afternoon!) Well, my bike was equipped with a Gorilla motion/touch sensitive alarm....and holy crap, there must have been a short somewhere. I couldn't get that sucker turned off for love nor money! Finally just drove away with the alarm screaming and some pretty distraught looking adults showing signs they were uncomfortable as hell about "not doing the right thing"......and CHASING me down in the parking lot or somehow cutting me off at the exit. Talk about "ride it like you stole it!" That's precisely what I did...to the nearest abandoned warehouse I could find where I promptly parked, got out my pocket knife and started cutting through the five-wire harness until peace was finally restored. Gained a whole new level of respect for car thieves AND heart attack victims that day, just from learning the effect of Adrenalin being pumped into a human body in sudden (over)doses. I've never reconnected it.
Beach Bum Posted November 15, 2015 #12 Posted November 15, 2015 Years ago one of the guys I worked with shut off my petcock then stood by "diagnosing" why the damn bike wouldn't start. I was clueless because you never go the KISS method when you're buddy is leading you down the path. Just as I was about to remove the tank to test the coils he came clean.
rougeray Posted November 15, 2015 #13 Posted November 15, 2015 On a 2nd gen or any other bike with the tank above the carbs, If your float valves are leaking all the gas will drain down into the crankcase. The height of the pump does not matter. All that matters is the height of the surface of the fuel in the tank and the height of the surface of the fuel in the float bowel, The higher level will drain to the lower level regardless of the heights of what is in between them. The only thing that will stop the flow is to block it off with a closed valve somewhere in the system. The valves in the float bowels are plenty to do the job IF they are in working condition. The 2 valves in the fuel pump are check valves that only allow flow from the tank to the carbs, so the pump will not help stop the leak down. Why would you have check valves to prevent back flow from the carburetors? I can speak from experience as I own an 07. If you install a fuel pump that is not designed to prevent flow from the tank when the engine is not running and your floats are not shutting off the flow of gas when the bowls are full it will leak down and create a hydro lock period. I had it happen 3 times before I figured out what was happening. Luckily it did not bend a rod or break a piston. I cringe every time some one recommends one of the aftermarket fuel pumps such as the "Mister Gasket". They work fine as long as the floats are sealing. Facet 40171: from Aircraft Spruce & Specialty Co. has a positive shut off when the key is turned off.
Flyinfool Posted November 15, 2015 #14 Posted November 15, 2015 Those 2 check valves are what make the pump pump. As far as I know the factory pump does not have a positive shutoff because the float valves can stop the flow from the tank IF they are working correctly. I agree that having a pump with a positive shutoff will add a layer of safety, but if I have a problem with the floats overflowing, I will use a band-aid approach to get me home, but shutting off a valve, whether the petcock or a valve in the pump, is not a fix for the leaking float valve. The leaking float valve can cause issues even while running.
vzuden Posted November 16, 2015 #15 Posted November 16, 2015 I'm pretty sure the 2nd gens' factory fuel pumps are designed with check valves to prevent fuel draining through them when not in use.
Flyinfool Posted November 16, 2015 #16 Posted November 16, 2015 I'm pretty sure the 2nd gens' factory fuel pumps are designed with check valves to prevent fuel draining through them when not in use. The factory pump does have 2 check valves, but they go the wrong way to prevent flow when off.
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