Triumphrat

eric nyc · 12-03-2012, 04:29 PM

Three weeks ago I had my carbs cleaned and rejetted and had larger pilot jets installed. Since then I've ridden about 300+ miles with no problems whatsoever. Yesterday I was riding back from the city and after about 5 miles the engine started sputtering. By the time I got to the next light it had died. I managed to start it again, but when I gave it any throttle it immediately sputtered and died. If I didn't know better, it sounded like it was out of gas. Aside from the fact that there was still more than a half tank left, I tried switching to reserve. No difference. After a few starts and stalls, it finally wouldn't start at all, even with full choke. Worried about draining my battery, I tried calling the garage that did the carb work since I assumed it had something to do with them, but they were closed. Ended up spending a couple hours watching a football game in a bar next door. When I came out I decided to give it one more try for the hell of it. Engine started right up with no choke and I was able to give it some throttle for about 30 seconds before it sputtered and died again. Called a cab and went home.

Garage still closed today (open tomorrow) but I had to at least move the bike to avoid a ticket so I took a cab back this afternoon. Bike started right up with normal choke, throttled fine. I wasn't that far from home and I had to move it anyway so I decided to try and make it. First thing I did was stop at a gas station a block away and top off the tank, just in case. Sure enough, more than half a tank left. A few blocks from the gas station she started sputtering again and died once at a red light. Was able to get her started and byt the time I got home she was running like nothing was wrong. I checked the petcock and the fuel line, everything seemed fine. wrapped the carb floats a few times with a screw driver to make sure they weren't stuck. Took it out around the neighborhood for about 30 minutes with no problems.

So any theories? I still want to take it back to the garage since they have a 30 day warranty on their work and I have to believe it had SOMETHING to do with them disassembling the carbs, but I'm worried they'll say it's something with the fuel system and they hadn't touched that so now I have to pay for the diagnostic.

norton74 · 12-03-2012, 04:47 PM

Maybe your fuel tank cap vent is not working properly.

Maybe it got fouled while you helping all those people right after Sandy.

BTW, thanks for your good deeds.

Sheepdog · 12-03-2012, 05:02 PM

Could be your fuel tank vent; if blocked they will stop the flow of fuel. Check out your vent line and rollover valve (the vent line is visible just above the intake rocker cover on the bike's right side). If the vent line is pinched or if the rollover valve is malfunctoning, your fuel flow will stop.

Von Dutch · 12-03-2012, 05:15 PM

I agree with the above suggestions about fuel...also
It might also be a clogged in tank fuel filter (above the petcock)
gummed up with a varnish type crap caused rapidly by ethanol
laced fuel. One thing I always do and recommend to you is get
some clear fuel line so you can see when fuel is flowing to carbs.

eric nyc · 12-03-2012, 06:29 PM

Please forgive my ignorance. Looked under the fuel tank and found a black hose not attached to anything that runs back into the air filter box with an L curve in it. Directly above that is a small spigot protruding from the underside of the fuel tank. To my untrained eye it sure looks like that hose is positioned to be attached to that spigot, but there is no fastening hardware or sign that there ever was one. Looked through the Haynes manual and couldn't find any reference. Is this the tank vent you guys are talking about? Seems clear now which could explain why the bike SEEMS to be running fine now. But I'm nervous about getting it to far from home/garage in case it happens again.

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Sal Paradise · 12-03-2012, 07:08 PM

That's the vent Eric. Its just slips on. If and when the problem reoccurs you can try taking off the fuel cap to manually vent the tank, just as a test.

Bron-Yr-Aur · 12-03-2012, 07:09 PM

Yes that is the vent. It just slides on, no clamps necessary. At least, since that wasn't connected, you know the venting wasn't the problem.

Regarding your OP, no worries about a 'fuel system' that they can blame. There is none, unless you consider the fuel line and filter to be that system. Have you checked/cleaned the tiny inline filter at the carbs? I seriously doubt the shop did, especially considering they forgot to hook up the vent tube.

eric nyc · 12-03-2012, 07:15 PM

Quote:

Originally Posted by kreemsicleT100

Yes that is the vent. It just slides on, no clamps necessary. At least, since that wasn't connected, you know the venting wasn't the problem.

Regarding your OP, no worries about a 'fuel system' that they can blame. There is none, unless you consider the fuel line and filter to be that system. Have you checked/cleaned the tiny inline filter at the carbs? I seriously doubt the shop did, especially considering they forgot to hook up the vent tube.

Is that the small filter inside the clear portion of tubing below the petcock? I compressed the hoses on either side and fuel seemed to be flowing freely there but I don't think it's been cleaned. As far as the shop reattaching the vent hose, I can't say they DIDN'T as I could just as easily imagine it came loose on its own with no clamp. This was the first time I noticed it. What function does reattaching it serve? If its as vital as assuring fuel supply to the carbs why is it just a slip on fit?

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Sheepdog · 12-03-2012, 07:52 PM

It both vents the fuel tank and prevents spilling in the event that the bike is laying on its side. In days gone by, the tank was vented by a hole in the gas cap. However, these days the EPA frowns on the atmospheric release of gasoline fumes, so the vent is connected to the airbox to facilitate the burning of those evil vapors...

Bron-Yr-Aur · 12-03-2012, 11:54 PM

Quote:

Originally Posted by eric nyc

Is that the small filter inside the clear portion of tubing below the petcock? I compressed the hoses on either side and fuel seemed to be flowing freely there but I don't think it's been cleaned. As far as the shop reattaching the vent hose, I can't say they DIDN'T as I could just as easily imagine it came loose on its own with no clamp. This was the first time I noticed it. What function does reattaching it serve? If its as vital as assuring fuel supply to the carbs why is it just a slip on fit?

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It would never just work loose, since its not pressurized. As fuel empties from the tank through the petcock, it creates a vacuum in the tank. Something needs to fill that space, so the vent tube allows air into the tank. If it's blocked, it's like sucking water through a straw, the fuel will never reach the carbs. But it's just at atmospheric pressure, so no problem with it falling off.

The filter I was referring to is in the fuel supply line. Follow the fuel line from the petcock to the carb. The filter is in the black T-junction where the fuel line attaches. Just pull the line (carefully) and the filter will either be in the black plastic or still stuck in the line. Needle nose pliers to perform that surgery. It probably will be fairly clean, but at least you'll be able to eliminate that possible gremlin.