| Author | Message | ||
     Darthane |
I change the oil in my Uly on Saturday (also finally got a dealership to confirm the flash in my bike), and gave it its first bath in a couple months and noticed something: Gas was steadily dripping out of the fuel vent hose that's behind the left-side peg bracket. I know what you're thinking - he overfilled the tank. Not even close...this tank had about 80 miles on it, which, given my average fuel economy, is nearly 2 gallons less than maximum capacity. It wasn't too warm on Saturday at the time - not even 70F. It was sunny. I couldn't believe how steadily this occurred. One drip every 3-4s and it continued through the entire oil change process - at least 20m. Could this actually be a contributor to my poor gas mileage? Why on earth would this be happening when the fuel level is obviously nowhere near the top of the tank? Is that much of the gasoline actually vaporizing and then recondensing in the lines? Obviously gas evaporates very quickly, so short of pouring out of that tube you'll never find a puddle, but my swingarm and the bracket were coated in what I now know was not simply acquired grime, but a buildup of gasoline MIXED with the grime. Thoughts? | ||
| Werewulf |
i have had a similar experience on my uly... it has quit on its own... at least i hope it has.. | ||
| Ulyscol |
Happened to me when my bike was new. Took out the paint on the swing arm too. I did not overfill the tank. It just went away on its own. | ||
| Stevem123 |
Well what I have noticed is a little annoyance that is attributed to heat causing the fuel in the tank/frame to expand a lot more than expected. When running hard on the slab and stopping to fill up I found that I either have to wait till the bike cools down before gassing up and even then I have to under-fill below the inner lip. A perfect example the other day I filled up to just below the inner lip right after comming off the freeway then parked it off the side for a smoke break. Within a few minutes the gas had expanded to the point of overflowing beyond the top of the tank! Usually I just do my smoke break first then gas and go but this showed me that a significant loss of fuel can occur due to expansion. I'll have to do more testing to see how low I have to fill to eliminate the overflowing due to heat expansion issue. I'm thinking along the lines of adding some kind of expansion tank to catch the overflow but I haven't figured a good place to mount it or if it would even work that well given the cap could leak it out anyway. The problem has been so bad on mine that I had to eliminate the charcoal canister because it would fill up with gas and the bike would bareley run till it cleared out. I never imagined the fuel would expand that much but it definitely will. I can't see where Darthane is having his issue but I suspect he had more fuel in there than he thought he had. I've only seen this happen right after a fill-up but who knows how much could be lost while tooling down the road until the level is far enough below the vent till it stops. BC Steve | ||
| Etennuly |
I don't recommend using the helmet lock on the Uly with a full tank of gas DAMHIK!  I wonder if when the tank was full it pushed some into the hose and it dripped out later. Maybe not, the vent lets air in the whole time the engine is pulling fuel out. | ||
| Darthane |
For those of you that say this went away on it's own, did it seem to correspond, perhaps, to an overall lowering of the engine temp? Like, the engine broke in, you switched to synthetic, fan started running less - and you noticed a corresponding drop in this gas-shedding behavior? I find it very hard to believe that it's expanding enough to take up 2 gallons worth of room in the frame, but if so, that's simply frightening...because anytime I fill up I'm just pissing money away as my bike pisses gas. | ||
| Panhead_dan |
Others have noticed the gas actually boiling while in the tank. This could explain the gas coming out the hose. It was "distilled".  it could happen. | ||
| Ft_bstrd |
And here I thought it was the big goofy galoot on top. Who'da thought? | ||
| Darthane |
Hmm...well, I guess a winter project will be to line the inside of the frame with heat-reflective tape and see if that helps any. | ||
| Sparky |
Run the tank vent into a catch can and reuse the effluent! | ||
| Darthane |
...the thought has crossed my mind; if not to reuse it, to at least get an idea of just how much I'm puking out. >.< | ||
| Dio |
These things will boil gas plenty when parked hot. If its quiet where parked, it is very audible until everything cools down some. You can even feel it if you put your hand on the frame. I like to fuel up when the bike is cool, (gas available 1 block from my house) and have a full tank ready for departure. Always expect some liquid fuel loss or vaporized fuel smell, when fueling in warmer temps or with a hot engine! | ||
| Ft_bstrd |
I fill it to the top every time. Then I put the cap on, fire it up, and ride like a friggin lunatic for 10 minutes. It burns that top part of the tank down pretty quickly that way. It's the gas that would have leaked out any way, so it's like getting free crazy rider gas. | ||
| Bertotti |
I fill to the till the fuel just breaks the top of the lower inner ring, whatever it is called. Haven't noticed any problems with it yet. | ||
| Blko8uly |
Mine boils and vents regularly. I was wondering if it may have to do with our High Altitudes here in Colorado. | ||
| Bertotti |
Didn't I read here some where of some one who installed one of the aux fuel tanks and ran the overfill line to it to vent through? | ||
| Unibear12r |
The new heat/low speed/mileage issues seems like a 08 Buell wide fuel mapping issue. From switching to the DDFI 3 maybe? On the bright side Buell just seemed to hit a home run on the 2ed remap for the 1125 for these issues so maybe a new map will soon fix the aircooled bikes. My 06 Uly fried me when I first got it but it was due to engine heat being blown on me from under the seat and not "excessive" heat in general. The air deflectors that now come on the Ulys (and a couple of sheets of tin foil) solved those issues. I never noticed that my Uly boiled fuel until my 1125 made me sensitive to it but it is such a small amount that it's a non issue. Out here in Cali the carbon evap cannister holds all the fumes and fuel droplets from the vent/over flow to be used by the engine later. (As long as the boiling is not too excessive!) No stinky garage either!  |
