maggasp

***Update*** I checked the petcock and sure enough a wire was completely broken off. I ordered a manual one from MPH ($45 now, btw) and he explained to me that even with a broken electric petcock, the fuel pump can still suck some fuel through. What I can't understand is why, since the petcock is not working at all, does the bike sometimes run great, and sometimes not??? I would think that a broken (closed) petcock would cause it to always run crappy. Maybe the thermal expansion causes a tighter seal in the petcock, finally blocking off the fuel flow? Maybe the heat btwn the cylinders + sucking hard causes the fuel pump to overheat?

Thanks for the info on the petcock, that seems like a reasonable (i.e. economical) fix. I'll call MPH in Houston this afternoon. Any other thoughts while I have the tank off again?? Should I replace the fuel pump while I'm at it?

It does have the original electric petcock, but would that failure cause the sputtering, backfiring, slow coughing symptoms? The fuel pump does start up when the key turns on, but i did notice that it sounded pretty weak and squeaky when I took the bike off the trailer 1 hour after the breakdown. But the next day it was strong and worked. As for a TPS failure and throttle body balance, to be honest that procedure sounds a bit like witchcraft to me. 2 years ago I increased the idle a couple hundred RPM by turning the idle screw, but that is all that I've messed with on the throttle bodies. Could a TPS failure, or unbalanced TBs cause a breakdown like this? I would think that it would just cause poor running, not stopping. (p.s. my tach broke again 10 miles into that same ride, so i can only guess what the idle revs are) But I'm willing to try anything. What has me most irritated about this is that even if I replace the petcock, balance the TBs, fiddle w/ the relays, etc... I still wont be confident that I've fixed the problem, and wont want to go more than a mile from home, uphill only.

Thanks for the quick response...I opened the fuel cap on the side of the road, and there was no "gasp". Once i made it home, and took it off the trailer, I started it up and it was still sputtering. I then started it with the fuel cap open, and it still sputtered. Only the next day did it seem to be fine. Also, I eliminated the tipover valve last year. Does 93 octane feel anything like Gold Bond?

It happened again, and I'm about to give up on this bike. This past friday, on my birthday, I went for a ride in the beautiful rolling country side, 75 degrees, cool breeze, perfect. Then it happened again, I dont know if it's Vapor Lock, or Tank suck, or ECU heat sink, or Fuel Pump, or relays, or just bad karma .... 30 miles from home, I was riding down the road at 45 mph, she started backfiring, then slowly coughed and sputtered to a stop. 1 hour later, started up, ran for 1/4 mile, did the same thing. Some cyclists rode by and commented on what a cool bike I had, as they cheerfully peddled off. I had to call a buddy to come pick me up in the middle of nowhere, on his day off. (Last year when this happened, I paid $40 to a 15 year old kid, and we put it in the back of his Ford Ranger with a huge sticker across the back window that read "Coon Hunters do it all night". There's a lot more to that hilarious story that involves under age cigarettes, catching a t-shirt in the cab on fire, and his buddies worried that I was going to rape him. Some info: '00 V11 sport 7k miles. All relays replaced 1k ago Adjusted Valves wrapped fuel line and fuel pump in racing heat shield new plugs yesterday, bike started perfectly in the garage, ran for 15 minutes, seemingly no problems. I have read everything I can on this gremlin. Last year the problem was more typical. 85 degree day, I stopped to make a call, problem occured when I started back up. That is what prompted the valve adjust, heat shielding and plugs. I've probably ridden 300 miles this season, without problems until last weekend. I'm stumped, any and all advice is appreciated. Thanks, Steve

Thanks for the replies. A few more bits of info... the rubber boots which connect the throttle bodies to the cylinders are slightly cracked. I never thought much of it, but it would make sense that this could be a source for the too lean mixture as air may be sucked in after the air flow meter. (does this theory seem sound?) Does anyone have a source for these boots and guidance on how to replace them? the removal and instillation does not seem very easy, would I need to remove the throttle bodies? I tried to put the idle screw back to where I thought it was before, but this didn't seem to help. Relays are an interesting topic. I never had issues with the Seimens relays, but from advice on this board, I replaced all of them two weeks ago with MGR-C20 relays. Could the new relay for the fuel pump be sticking and causing a fuel flood? If this is the case, the spark plugs may be fouled. The power commander is something that I've been considering, not for performance benefits, but for smoothness.

I just got back from a really nice ride this afternoon, and after I pulled into the garage, I thought I would increase the idle a bit by turning the idle screw on the left throttle body. (The reason I did this is that when the bike is hot, and I pull in the clutch, the revs would dip just low enough to cause a sputter, or sometime a stall) So I turned the idle screw 1/2 turn one way, and the revs went down, then tured back the other way 1 full turn and the revs went up. Great...not exactly. The bike idled at about 1200 revs for a couple minutes, then started to sputter like crazy. Now when I try to start it, it coughs, sputters, then dies. Next a really wierd thing, with the key off there is a small whirring motor that every 30 seconds or so, turns on and runs for a few seconds. Back behind the right hand throttle body somewhere. I assume it will run down my battery. If anyone has any ideas as to what I have done, please help. I just put new tires on for spring and am really bummed at the thought of it sitting in a shop till hot August. Thanks in advance.