Soon to be for Sale, '00 V11

[maggasp]

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

[emry]

Tank suck is easy to check, ride around the block until it dies. Open the filler cap. If the tank jumps and the previously mentioned 15 year old is sucked in, in his entirety, then you have a tank venting problem. No jump and inhaled minors then not a tank suck problem, wait and try something else.

 

Vapor locking should only occur after riding and then parking, then restarting; due to heat soak. Eliminate the tank implosion problem first, it is easy solve - just ride with the cap open. But no wheelies, soaks your man berries with fuel. NOT GOOD.

[maggasp]

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?

[docc]

 

 

Does 93 octane feel anything like Gold Bond?

 

Actually, no. It would feel more like an in-cab garment fire . . .

 

This sounds suspiciously like Guzzimeister's TPS failure. Is she due for a full TPS, throttle body balance?

[Kiwi_Roy]

Next time it happens, pull a plug out and check the spark.

Does the fuel pump fire up for a few seconds when you turn the key on?

Try swaping the relays around, see if the symptoms change.

I assume it cranks over OK

 

Roy

[helicopterjim R.I.P.]

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.

 

 

If Tx Redneck was still around he might have had to ask you a few questions about that! Sure do miss a guy I never met ....

[OldButNotDead]

the electric petcocks seem to have a very bad reputation; got one of those?

[maggasp]

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.

[jrt]

I could easily see the petcock as malfunctioning in such a way that it only dribbled fuel through. Not highly likely, but a distinct (paranoid) suspicion.

Also- no one has mentioned the fuel filter. Have you ever changed it?

[Steve G.]

I've experienced ALL the problems you've gone through, and more. Do yourself a favour and replace the electric fuel petcock for a manual one.

My theory, yes, fuel heats up in the line from the petcock to the fuel pump. The heat can be vastly reduced with heat shield, but not eliminated. The problem is, the electric petcock closes shut when you shut the thing off, thereby trapping that pocket of vapourised and pressureized fuel. The manual petcock allows the vapourised fuel to harmlessly vent up into the tank at it's own leisure.

I know you are frustrated, close to getting rid of it. Just one more step is needed to eliminate this problem.

Whomever decided on this electric petcock at Moto Guzzi, needs a kick in the sack!

 

Steve

[antonio carroccio]

With 7.000 miles in ten years, should you maybe make the choise and ask your self:

Should I keep it or modify it?

[maggasp]

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?

[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?

[Steve G.]

***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?

 

 

I'm sure the manual petcock will improve things dramatically.

 

Steve

[luhbo]

The electric petcock opens easily enough as soon as the pump begins spinning. I once had a broken one, too, and the bike run flawlessly with it. So don't expect too much of your new petcock.

If the pump sounds weak and squeaky the problem definitely is a vapor bubble. The solution is easy: switch on and off the kill switch until the bubble has found its way back into the tank and the pump sounds normal again. For me it always works - even if it may take up to 10 on/off cycles. In case it does not (in the US some things work different) you could slightly and carefully loosen the hoseclamp at the pressure regulator in order to let the "gas" out. As fuel spitting over a hot engine may sound weird to the one or other I'd call this an IAEF-measurement.

 

Hubert