This 60 Mile Range Stuff Sucks!
 

I have a what I think is vent related problem. After a fill-up the fuel runs out the vent hose and drips out under the bike. This does not happen immediately, but after a short while when parked on the sidestand. I have no problem once the fuel reaches the 3/4 point or less.

It would help to know how the vent line is routed within the tank. As near as I can tell, the vent opening in the tank is located on the left (clutch side) about 3/4 of the way up the inside. I'm puzzled how this works as this location is under the fuel level when the tank is full. Seems that the fuel would drain to the point it reaches the top of the internal vent opening. That is unless there is some type of check valve or special routing.


Also, does anyone know if the filler cap is vented?

Re: This 60 Mile Range Stuff Sucks!
 

I have this problem if I go over the bottom of the silver metal overflow cap's bottom edge too. I find that this is 100% full once it reaches the -bottom- of it that extends about 1/4" into the tank.

I tend to get a range of 135 miles plus or minus 5 until the RESERVE indicator comes on. I've been able to travel 151 miles no problem so far.

Re: This 60 Mile Range Stuff Sucks!
 

To answer my own question... The VTR fuel tank is vented to the atmosphere via a labyrinth built into the fuel cap.

Tonight I swapped fuel caps between my two VTRs. I notice what looked like a vent hole next to the hinge. On closer examination, I discovered three screws. Next thing you know I have it apart on my bench. It was a bit dirty. Though not bad enough that I would consider it the cause of my problem.

Maybe this is nothing more than a plugged vent in the fuel cap.
I'll try it out tomorrow and see if this fixes the problem.

If curious, this is VTR #1
https://www.superhawkforum.com/viewtopic.php?t=973
and VTR #2
https://www.superhawkforum.com/viewtopic.php?t=1171

Re: This 60 Mile Range Stuff Sucks!
 

Well finally fixed the problem. Basically, I gave up trying to figure out the Honda vent system. Seams my fix of disassembling and cleaning the fuel cap didn't do any good. On closer inspection, there are some seals that prevent the labyrinth vent from functioning. So I removed the seal at the bottom of the key lock cylinder and drilled a small hole from the labyrinth into the key lock well, effectively breaching the cap seal. The cap now vents directly to the atmosphere. I disabled the under tank vent by plugging the vent tubes. I just got back from a test ride and all appears well. No running problems and more importantly, no fuel leaks or drips.

My bike sputters out if I fill the tank to the metal tabs like micronis said. This just happened to me yesterday in fact. I have to stop and open the tank a couple of times before it's corrected.

On a similar note, I've rerouted the venting tube because when I ride in the rain it gets clogged, leading to the same sputtering/dying.

Well i filled up yesterday and rode until the fuel light when on...i got a whopping 145 miles....then i turned around and ended up back at the gas station at 160 miles. not too bad i guess 47mpg. drastically better than the 100 per tank i get around town!!!

Great job, SillyHawk! What was your average speed/rpms during your run? Just curious. I find runs over 100mph change my mpg quite a bit.

I also find I cannot access the last 0.4 gallons of gas in the tank as it'll be dry at 3.7 gallons and die on me. How can I access the remainder? Why did Honda do this?

well after many miles of lane splitting i started cruising between 70-80 mile an hour. sea level

Whoa - are those stock carbs?? I never have gotten close to that after rejetting .... I'm extremely happy if I get 40mpg.

Yep. I average low 30's without seriously flogging it. I'd be happy with 40.

I get a reliable 43 mpg or so with mostly interstate or open road riding with stock jetting

i have the bike jetted but that 145 was a strictly highway/freeway run (at sea level the whole way)...thats why i did it too see what kind of range i could get!

around town i get the same shitty 30+ mpg you get...

I'm now getting 40 mpg @70-80 mph steady cruise. In town it drops to 32-34 mpg. Not great but OK considering I'm still running #50 pilot jets. My problem now is the dam light comes on at 80 miles. Not going to attempt a fix until the next time I need to remove the tank.

80...wow! mine around town comes on usually after 95 miles. and the tank on these things are so easy to prop up and work on i do it every week just for fun!! ha-ha

I know that to change the point the red light activates, I'll need to remove the sending unit from the bottom of the tank. This is much more effort than just prop-ing up the tank. But if you know a better way... I'm all ears :)

I got 41 mpg once. I also found out last week that the superhawk tank holds 4.127 gallons. Oops. guess I ignored the flashing low fuel indicator too long.

Just went on my first overnighter since putting the S'Chicken back on the road. (Met my brother at the national BMW rally in VT) The VTR did very well. I was paranoid about gas and have been filling up before the RLOD came on, but today I went 131 miles until RLOD. Not bad, not bad at all.

Normal riding..120 till she lights. Fast(er) riding and it goes to about 105 or so. And I have only found the bottom of the tank once,, Xmas day, "Really honey, just a quick ride before dinner"...Who would have thunk, no gas stations open, in the middle of knowhere Tx...