Stalling/Hesitation During 90+ Temps Fixed

[willms81]

Had the bike for nearly two and a half years now (bought it with a mile on the OD off the showroom floor) and never had an issue. Last June I ride to school, no problems. Leave my morning class, grab lunch and ride across town to the main campus for my afternoon class, again no issues. The bike sits from 12:00pm to 4:45PM in the blaring Texas sun. Air temp is about 105F. The bike is parked on a very slight incline nose first (maybe 5 degree slant, nothing real bad). I get out of class, start the bike, it starts fine, put it in gear, take off, and it starts to sputter and dies out. Try to restart it and it just cranks, won't actually start. I play with it for a while (turn it off, on, off, etc) finally it starts to fire then eventually starts. It idles fine but as soon as I put it in gear and start to let out the clutch it dies. This happens a few more times. Call the wife and tell her to bring the truck so I can load the **** thing in the back and at least get it home (I live 45 min away from my college). While I'm waiting I pull the tank and make sure the injectors are all plugged in, and check any of the other electrical connections. I start it, it does the same sputter/die when I get it in gear. I finally get it to go while in gear by revving the **** outta it because at this point I'm less than happy with the thing. I make it up to second gear (still in the parking lot) and when I let off the throttle it cuts out again. It does this a few more times but seems to be getting better. I finally get it to where I can shift and it won't die. I nurse it back to my house with no more issues. I decide to take it to the local stealership to get the 7500 service done and the recall taken care of. A week later I get it back and ride it home with no problems. I ride to and from school Tues and Wed of this week with no problems (both days it was in the mid 70s or mid 80s). Today it decided to get hot again (around 95F or so). Go to my morning class and afternoon class, no issues. Today after my afternoon class SAME EXACT thing happens, and once again after screwing with it I finally get it home. Except this time when I turn it on (for the first time after class) then turn the kill switch on I here a short hiss coming from under the tank but it stops. I start it, and I hear an odd hissing type noise coming from under the tank. I put it in gear, try to take off and it sputters and dies. As long as the hissing is coming from under the tank it dies out. After some time it stops and will run fine for a few seconds. I also notice the hiss goes away when there is something else that turns on in the front of the motor and everything is fine. It sounds similar to the fan coming on but not nearly as loud. It seems like when I have this noise the bike runs normally.

This was the original issue I had.

Did A LOT of forum and internet searching and noticed there seems to be other Bandits with this issue, 650 and 1250. Some guys swear that opening the tank prior to turning the bike on will keep it from happening. I tried it, never worked for me. Others suggested to make sure it has less than half a tank before parking it in the sun for the day. While it probably would work this is not a fix, only a temporary solution. I want the situation fixed.

Fast forward a year. Getting sick of not riding my bike ~5 months out of the year to to the high temps (plus the AC went out in my car so while I'm waiting to get my new compressor ordered I want to ride the bike) so i start digging around again.

Stumble on a random thread on some random forum where a guy with a 1250 Bandit mentioned having fuel in his EVAP canister when he took it to Suzuki with the same issues I had. Pull out my Haynes Service Manual and start reading about EVAP. Pull the fairing off and sure enough I have the crap on my bike. Kicker is this is only supposed to be on California bikes...NOT one I bought in Texas. Anyway, pull the tank and the EVAP line that runs from under the tank to the hard metal line that runs along the frame rail and the tank actually sits on top of and it has liquid fuel in it. Quite a bit poured out actually.

Theory time:
If the tank vents pressure into the EVAP system (which is nothing more than a charcoal canister) and these line end up with actual fuel in them, not just vapor then the tank can no longer accommodate for the rising pressure when sitting in direct sunlight and over pressurizes the fuel system leading to the issues I described earlier.

The fix:
Pulled the rubber hose that ran from under the tank to the metal line for the EVAP. and replaced it with a new rubber hose and ran it through the frame next to the original vent tube. Removed the charcoal canister and all remaining EVAP hoses.

Testing:
Rode the bike and let it sit in the sun for a few hours at the beginning of the week after doing the above fix. After sitting in the sun and 95+ temps bike started, shifted, and ran great with zero stalling or hesitation. Yesterday did it again except this time after going for about an 80 mile ride and filling the tank at the gas station a couple blocks from my house to make sure the tank was full, it sat from 11am until 4:30pm at 95+ degree temps again.

Went out to start the bike and smelled fuel. Looked at the new vent line I installed and saw a small amount of liquid fuel leaking out as well as watching the fuel vapors escape.

This tells me my theory is probably correct. Heating of the fuel in the tank causes expansion of fuel and pushes liquid fuel into the EVAP line ultimately blocking it from venting the vapors like it is supposed to.


I am going to ride it to work this week and see if this is a permanent fix, but so far this is the best idea I have came up with that actually seems to work and make sense.


Maybe others can find this helpful or chime in with personal experiences involving this issue.

Sorry for the book, but I wanted to be as detailed as possible.

[wanabeguru]

Well done

[Stretch30]

I have always assumed it has something to do with the evap canister, just haven't gotten around to removing mine. I only typically have issues when I go into 4th gear at low RPM. If I keep it about 4K RPM in 4th it will continue to run. I don't have any issues in 1st thru 3rd though.

[willms81]

Originally Posted by Stretch30

I have always assumed it has something to do with the evap canister, just haven't gotten around to removing mine. I only typically have issues when I go into 4th gear at low RPM. If I keep it about 4K RPM in 4th it will continue to run. I don't have any issues in 1st thru 3rd though.

I read some threads on different forums that spoke of this issue, but I don't think my issue is the same.

Most of what I read regarding the 4th gear stall isn't temperature related it seems.

[blchandl2]

Mine has this issue also. I bought a half cover to keep the sun off since the windscreen focuses the sunlight on the dash and melts it. No more scorched buns, bird poop, melted dash, or stalling.

[willms81]

Originally Posted by blchandl2

Mine has this issue also. I bought a half cover to keep the sun off since the windscreen focuses the sunlight on the dash and melts it. No more scorched buns, bird poop, melted dash, or stalling.

What windscreen are you running? I have a Puig in dark smoke and I have never had an issue with a melting dash here in Texas.

[blchandl2]

Currently the 22" Vstream. Melted the first dash when using the Madstad. Bought a new dash ($170) and melted the new one within a month with the Vstream.

[willms81]

As long as the cover works, then keep using it.

I could have just made sure I had less than a half tank before I parked it for the day at school (work now) but to me that isn't fixing the underlying issue.

[blchandl2]

Originally Posted by willms81

As long as the cover works, then keep using it.

I could have just made sure I had less than a half tank before I parked it for the day at school (work now) but to me that isn't fixing the underlying issue.

I agree, it is all just a band aid for the real problem. I have not gathered the nerve to rip the canister out yet. I don't mind the cover too much, it provides multiple benefits.

[willms81]

Originally Posted by blchandl2

I agree, it is all just a band aid for the real problem. I have not gathered the nerve to rip the canister out yet. I don't mind the cover too much, it provides multiple benefits.

If it keeps your cluster from melting then I'd say leave it as is.

I'm just offering my experience on how I was able to alleviate the problem and maybe help some other riders out at the same time.

Sent from my Vortex using Tapatalk 2

[achesley]

BMW oilheads had this very same problem as I did with my '95 R11GS. Put the tank vent to ground and lost the canister. Problems solved.

[Tazman2]

Excuse my very paranoid self but won't you have gas coming out randomly and possibly hit the exhaust and then ignite itself!?

[willms81]

Originally Posted by Tazman2

Excuse my very paranoid self but won't you have gas coming out randomly and possibly hit the exhaust and then ignite itself!?

If you look at the original vent tube, it is vented at the bottom of the bike BELOW the exhaust. My second one follows it and stops even with the first.

Trust me, I had that same thought originally.

[DaveC]

does your mileage improve? Had a Yamaha 650 Classic and it refused to start or run when the temps were below 34 F and it was getting a paltry 35 MPG, with the emissions canister removed and the plumbing rerouted it ran when it was 20F out and it got 45+ MPG That emissions junk is a fuel waster. If you have a evap canister you would do well to find a different use for it. It is no wonder the air quality in Los Angeles has not improved, they are dumping raw fuel into the atmosphere.

[willms81]

I haven't had a chance to figure my MPGs yet. Currently the bike is apart awaiting new header gaskets. I found a small crack in my header after the cat and took it to get welded over the weekend when I changed my oil/filter and brake pads.