mystery condition.

[doorsfan83]

My 80 special runs great around town but on a trip over ten miles she will start cutting out at a sustained rpm and die at a stop sign. I of course started with sea foam. Didnt help. If I turn her off for a minute then start her back up she will run fine for a little while then do it again or she might run fine for 50 miles. It makes no sense. Any help would be great.

[DGXSER]

Does it feel like it is just quitting like an electrical issue or does it sputter in and out like a fuel issue?

[Bigfoot]

Sounds to me like it is running out of fuel. Check your fuel lines for kinks. If not that, the screens on your petcocks could be plugged up.

[skids]

Two things:

The fuel cap vent may not be venting which can cause a vacume in the tank and fuel starvation.

The fuel filter or fuel tower in the petcock(s) is plugged.

One thing to try is to switch over to prime so that you are not dependant on the vacuum line (or lines on the standards). I have two xs11s that act up like that when they are not quite up to running temp and if I switch the left petcock (standards) to prime, it gets its fuel suddenly and runs good again.

My 80 special runs great around town but on a trip over ten miles she will start cutting out at a sustained rpm and die at a stop sign. I of course started with sea foam. Didnt help. If I turn her off for a minute then start her back up she will run fine for a little while then do it again or she might run fine for 50 miles. It makes no sense. Any help would be great.

[doorsfan83]

May have found it.

It seems when we were putting the fairing on and reinstalled the tank we didnt get the lines under the air box bolt both sides were kinked 90 degrees I am assuming that was the problem wont know for sure til I take it for a long ride. I thought it could be the cap tried it with the cap open so that wasnt it petcocks were gonna be my next try but hopefully the problem has been solved. One more question for you guys. when Im riding at night with my brights on they will sometimes brighten and dim back and forth annoying really someone please tell me this has nothing to do with the stator.

[DGXSER]

Unfortunately, this is very normal. The bikes charging system basically is weak from the factory, so when you let off the throttle the light dims down, when you rev up it gets brighter.

[3Phase]

when Im riding at night with my brights on they will sometimes brighten and dim back and forth annoying really someone please tell me this has nothing to do with the stator.

Doors, the lights change while you're riding at speed or when you come to a light and stop?

My lights were pulsing bright/dim/bright while I was out riding last weekend and it was because the cigarette lighter in the fairing was stuck pushed in. The lights would pulse as the lighter element heated and cooled for ~70 miles until we got to Santa Maria.

If you don't have a cigarette lighter or a fairing check:

the headlight bulb. The RLU might be toggling between the bright and dim elements if the bulb is going out. It's supposed to do that.

the Headlight fuse and fuse clips

the main harness grounds and the other connections at the regulator/rectifier

the engine/frame ground at the mid-drive.

the battery connections

the ignition switch and connector in the headlight shell

the headlight connections and switches

the RLU and its connections



Regards,

Scott

[Getty]

I have rebuilt petcocks, eliminated octopuss, replaced gas cap seal, and cleaned out air hole in cap.

Mine still has the gas tank vacuum problem. Once and awhile she looses power. I take a good look around for danger, then pull the clutch in, take key out, open up gas tank with key, close cap, put key back in and everything is fine.

Not sure if thats your problem. I cant figure out how to fix it.

[TopCatGr58]

Hey Getty,

Did you actually take apart the gas cap to get at the little vent disc to clean the hole? The whole disc can get gummed up. IT's been a while since I took mine apart, but I remember there's a path that the air has to take THRU that vent hole inside the cap to be able to vent to air, so make sure that there isn't a bunch of gummed gas and varnish in where the vent disc is, that should allow it to vent properly and not vacuum lock!
T.C.

[Getty]

Yep, took it all apart. Even drilled that hole bigger not much, but enough to ensure that it was a good air hole.

[planedick]

Me too

I have experienced that problem and found that it always happened with a 1/4 tank or less and after stopping for a few minutes and then going again. Seem as the bike sets the hot engine heats the fuel and creats a pressure in the tank that is released through the tank vent. When I go again the air cools the tank and creats a vacuum which causes the bike to stumble and quit at idle. I just open the tank and quickly close it and on our way again...

[TheFrugalTech]

I had the same issue with my 78 Standard randomly dying like it was out of fuel. For a while I thought it was the petcock filters since I would stop and top off the tank then things were fine for 75 miles or so. Also thought it was maybe vapor locked somehow since stopping for 2 minutes fixed it. Got to the point it began to happen more often. Noticed once when I stopped to let it cool, and was in the middle of nowhere, that there was a slight sound like a vacuum seal being broken. Never would have heard it if I was in town. Checked the cap vent when I got back home and it was plugged. Took it apart, cleaned everything, and put it back together. Bike has never run better.
Everything else that I thought was resolving the problem all equated to the vacuum bleeding off. Either by just sitting or by opening the tank to top it off.
Hard to believe one very small hole can cause such headaches.
But then again, I did marry the wife.

[XSokieSPECIAL]

I have rebuilt petcocks, eliminated octopuss, replaced gas cap seal, and cleaned out air hole in cap.

Mine still has the gas tank vacuum problem. Once and awhile she looses power. I take a good look around for danger, then pull the clutch in, take key out, open up gas tank with key, close cap, put key back in and everything is fine.

Not sure if thats your problem. I cant figure out how to fix it.

Partsnmore has new gascaps for XSs for $34. I got one and put the lock from my old one in it so my single key still works for both.

Greg

[CatatonicBug]

I think I have the REVERSE problem. I can tip a mostly-full tank on it's side for a short time (when removing to clean the carbs) without it leaking. However, when I walk up to it after it has sat outside for a while, I smell the strong odor of fuel. That is what made me change my fuel lines this last weekend, but the smell is still there. Is that normal? I can't imagine keeping that smell in a closed garage for any amount of time, so there's got to be something wrong.

[Yahman]

This is why I love this place!

I've encountered this problem 3 times with my XJ in the last 2 days. I thought it might be in the carbs, but it runs great.
I usually keep my tank on the full side, but I let it get down to a quarter full this week.

Thanks for the tip about the vent in the gas cap.

Larry