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Discussion Starter #1
I have an '07 T100. When I bought it i had the dealer do the pipes/airbox/ai/k&ns before i ever rode it. It has only had one problem. Sometimes when I "exercise" it, the engine quits dead when I let off of the gas. It acts more like the ignition quit than running out of fuel. No coughing or sputtering or anything. This has happened 4 times, each time with a full tank. The first time I got to the side of the road and tried to get it started, let it set for a while and tried again. Nothing. Then on a whim I turned the petcock to reserve and it started right up. The next 3 times I turned to reserve while the bike was still rolling and it started right up each time. I cannot think what could cause this except a faulty petcock. Has anyone else expereanced this, and if so, what was your solution.
 

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I happen to have the petcock off my tank and sitting in front of me. What you have is a 2.5" tube with a fine mesh screen (filter) on the tube. This is the normal position. For the reserve position, all you see is another fine mesh screen beside the first tube--this allows one to get all or almost all of the fuel out of that which is on the left side of the tank--there will still be fuel on the right side of the tank.:(

The only thing I can think of that would cause your problem would be a stopped up screen on the 2.5" tube. I would, however, think that it is more likely that the reserve screen would be more likely to stop up from crud in the fuel tank because it sits at the bottom of the tank.

Just for kicks, the next time it happens, unscrew the fuel cap and see if you hear any air rushing into the tank. Try to start it with the fuel cap loose and see if that works. If it does, take the fuel cap off when you get home and take it apart using snap ring pliers and free the vent in the cap. The cap should vent into the tank but not the oposite direction. OR...if your bike is still under warranty, take it to the dealer for a replacement fuel cap--dealers have replaced many due to faulty venting.
 

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What's she idling at?

Hey rvance,
After shes warmed up, whats the idle? Quick stopping with too low of an idle and my bike dies too. My idle sounds great at about 700-800 but thats seems too low. Right around 1000 is good to stop the phantom dying problem for me. Use the idle adjustment knob. Can't live without it.
 

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Idle speed, petcock, etc.

+1 for both the bad petcock causing the bike to run in reserve, but not on the main fuel setting, and the idle speed possibly being too low.
I don't have enough time on the T100 yet to know if this condition will persist, but it seems that it takes quite a while for the engine to warm to the point where the idle is high enough to avoid stalling at stoplights.
Currently, I have the warm engine idle sitting around 11-1200 rpms.
Even at that speed, if idled long enough I will hear an occasional sudden, sharp misfire, then a return to normal running.
This is at about 1500 total miles on the bike, and I haven't yet checked the crank position sensor air gap, or the carb balance.
Bob
Hey rvance,
After shes warmed up, whats the idle? Quick stopping with too low of an idle and my bike dies too. My idle sounds great at about 700-800 but thats seems too low. Right around 1000 is good to stop the phantom dying problem for me. Use the idle adjustment knob. Can't live without it.
 

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Discussion Starter #5
Thanks for the Ideas

Thanks for your thoughts guys.
Redbird: Your description of the petcock is as I imagined it. It is counter intuitive (sp?) that the problem is reversed from what you would expect. My next thing obviously needs to remove and inspect the petcock. I'll just have to tough it out and burn up that full tank as fast as I can.;)

Surfdogx: The warm idle is around 1050. I like the sound at 750-800, but Bonnie doesn't. The engine was only cold one time when this happened. It warms up fine usually in the first mile.

BMWBOB: Odd handle for a Triumph site. I admit if I could afford another bike without giving up the Bonnie I would like a R90s. Then a HD. After that a Guzzi or Duc. Anyway, when the engine quits, it is not at low RPM. Sunday I had just come down from about 8000 to around 5000 when it shut off. I don't know where the rev limit is supposed to be, but the tach goes by 8100 in a blur. The bike never seems to run out of breath. The guys at the dealer (British-USA in Houston) seem to know what their doing. All my experiance tells me this is an electrical problem from the way it acts, except there is no electrical connection to the petcock. It doesn't do this very often. Most of the time I can run it up to 8k in the first 4 gears and just keep flying.

I saw something on another thread about a check valve on a hose under the tank, so I guess the procedure is
1. Burn up the gas as fast as I can.
2. Remove and inspect the petcock.
3. Check the gas cap valve. (Does this require disassembling the cap?)
4. Look for some kind of check valve under the tank.

I wish the pingel petcocks weren't $100, but then i shouldn't need one.
 

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Thanks for your thoughts guys.
Redbird: Your description of the petcock is as I imagined it. It is counter intuitive (sp?) that the problem is reversed from what you would expect.
Actually, it makes sense. If you have contaminents in the fuel, it makes sense that it would plug up the screen that's being used. If it settles to the bottom, then it would only plug up the reserve side if you switched it to reserve. No flow - no clogged screen.
 

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The diagnostic for the gas cap valve doesn't require disassembling it. If the problem goes away when you loosen the cap to allow some air in, you'll know the cap's the problem. If it doesn't go away, the cap's not the problem.
 

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Possibilities

[Q Then on a whim I turned the petcock to reserve and it started right up. The next 3 times I turned to reserve while the bike was still rolling and it started right up each time. I cannot think what could cause this except a faulty petcock. Has anyone else expereanced this, and if so, what was your solution.[/QUOTE]

Just off the top of my head, and regarding your post above, are you looking closely at the position of the petcock?
What you describe sounds like you have switched to reserve instead of run to start the bike. If it quits when you start out and runs with what you consider reserve it might just be that you have the positions wrong. That is to say you are starting off on reserve to begin with, when it clogs up and stops, you turn the petcock and it runs okay.
 

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Discussion Starter #9
Even better

Thanks guys
Pokeyjoe: Excellent point. Makes sense.

Balto: I have a new NewBonneville popup gas cap coming in anyway, but I may leave the stock one on just so I can check that.

Koifarm: I'm an IT director for a payroll co. I give everyone around me a chuckle every day when I ask a client "are you SURE it's plugged in. You make a valid point. For the first few tanks I thought ON was the up position. I finally looked at it with my glasses on. I'll bet when I take the petcock out ONE of the screens will be clogged.
Each time it has happened the tank was almost full because I top it off at the start of each ride, no matter how low on fuel I am.
Thanks:
ronnie
 

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An easy, unsanitary way to check the gas cap vent is to remove the cap, wipe the threads as clean as you can get them and put the threaded end into your mouth and suck on the cap--you should be able to suck air in, and you should not be able to blow air out through the cap. You can actually hear the check valve working when you change from sucking to blowing.:D

The hose under the tank is connected to the "tip-over" valve. That hose is for draining off fuel when you over-fill the tank at fill-up AND for releasing pressure inside the tank--remember, the gas cap vent does not allow air to flow outward, so there has to be a means to vent pressure out. When the bike falls over as in an unscheduled dismount, the "tip over" valve shuts off and fuel cannot escape out the overflow hose (safety device to keep you from becoming a crispy critter).

rvance....the more you have described your problem, it sounds to me to be all electrical with the petcock only being a circumstantial occurance. Your description of your tach is very interesting. Remember this is an electrical tach driven by the igniter (this is your computer ignition brain so to speak). These tachs are not really accurate; however, I doubt if they are off much over 100 rpm. Your rev limiter will be VERY accurate and is set at 8000 rpm. If your tach goes very far above 8100 rpm before the rev limiter kicks in, I think you may have found your problem. I would bet you have a bad igniter if this happens. Otherwise, the pickup coil (also referred to by some as the crank position sensor) is a likely culprit, IMHO.

If the problem is very easily recreated, I would suggest taking it to the dealer if you still have warranty left.

Good luck,
 

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An easy, unsanitary way to check the gas cap vent is...
replace the check with an inline fuel filter.

that tank sucks air when running engine is demanding,
pressurizes when it's shaken, and pressurizes sitting in the sun...let the gas tank breathe.
 

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Discussion Starter #13
Tip over valve

Redbird:
Not having a check valve on the vent tube is useful. I was laying in a ditch with my 99 Magna on top of me. Having gasoline running on my crotch helped me get motivated to pick up a 500Lb motorcycle. If I had a working check valve, I might still be laying there. But, that's another story.
;)
 

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Discussion Starter #14
Inline filter

Modre:
Excellent solution to the check valve issue. Question: no problem as long as I'm not under the bike, right?
 

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Modre:
Excellent solution to the check valve issue. Question: no problem as long as I'm not under the bike, right?
I'm not sure what year the "technically advanced" tip over valve became vogue, but before that stellar achievement we had no use what-so-ever for one...we enjoyed a pin hole in the cap itself to vent the tank for decades, and I can't recall a list of people having problems with tank vacuum and no clue as to why the machine acts contrary...so it's your call.

a lot of this stuff came along after they already had it right when college degrees had too much time on their hands and the service department wanted to improve business on that end. these "retro" bikes are like a kit...once you take off all the fluff improvements, you have a machine...like the old days.

the real danger is siphoning...don't swallow...spit real hard and in ernest...
2-3 days of gasoline burps will weaken anyone's knees.

and don't get under it. keep your monster on the leash.
 

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How many miles are on your bike ?

If its been sitting for a long time, I'd bet that the petcock is plugged up. Clean it and see what happens, also the advice about the fuel cap is also very good and a cheap fix.
 

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Discussion Starter #17
Mispoke on the RPM

I mispoke on the RPM. I guess I was thinking of another bike. I think I shifted my Magna at 8100. I have been shifting the Bonnie at 7600. Today I ran it out it 3rd to check the rev limiter. It cuts out sharply @ 8000. The needle seems to move from 7500 to 8000 faster than from 7000 to 7500, but things are all starting to happen fast then. I have heard that guys with stock bikes feel that their engines are "running out of breath" at 7200. When I bought the bike they were giving away $1000 free accessories, so i just had them put on what sounded good and Jim at British-USA recommended. I waited a month and the NH Togas were back ordered so I told them it was OK to go with Wassels because it was time to ride. I really expected to get it with a half-assed state of tune. I couldn't be happier with how it runs. I rode the sh** out of it today and no quiting problems. I'll clean the petcock and put in fresh gas in morning and then get some sorely needed fresh air. The tank just looks rusty inside, so I ordered a tank lining kit. Not the Kreem, this one is KGR Gold or something like that. It puts in a tougher lining than the Kreem, or so I hear. I'll Let you know how that all goes.
Thanks:
ronnie
 

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Discussion Starter #18
How many miles are on your bike ?

wenzel850:
1375 miles. I didn't pick it up until the end of April 2008. It was a "leftover", hence the promotion. I would have a lot more miles on it, but I spent all summer out of town getting a data center ready for hurricane season. Finished just in time for Ike. I just haven't had that many weekends with decent weather when I was in town. Even with that, it hasn't set up for more than a month without being ridden and then it had Seafoam in the gas. I really don't know why it's so rusty inside.
 

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Discussion Starter #19
No rust, now what?

I took the tank off last weekend and drained all the gas through a white towel. Not a speck of anything. Blew out the petcock with compressed air and again, nothing. There is no screen on the "normal" inlet tube. is this normal? I have already ordered a gas tank lining kit so I guess I'll go ahead and apply it this weekend anyway. Maybe it is an electrical problem and when I shift my weight on the seat to turn the petcock to reserve, it fixes it. I cannot find any evidence to support this, though.
 

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