WTF?

[Don G]

Every one has heard that Motorcycling is dangerous right? OK, how is this for dangerous, I was in the shop last night building a coil bracket for my Ambovert, I noticed that I could hear fluid running, I scoped it out and found one of my V700's pissing gasoline at an alarming rate, this is what I found:




This petcock was installed late last year, apparently you should not use Teflon tape on the threads, as you know that Guzzi took a short cut in the design of this cock, rather than using a jam nut they figured that you should piss around with shims and gaskets to get the orientation correct, so what happens? Give it that little bit extra to make it line up, well with the Teflon being there, that little bit of a tweak may unwittingly produce the effect of tons pressure. Looks to me that is the end result in this case, I recall installing the cocks , I was mindful of the fact that the tank is over 50 years old and did not exert the amount of force required to bring forth a fart, all the same there was enough strain on the fitting to pop the end off.
I can only imagine the carnage if this had happened at speed on the open road, its a good thing it did it at rest,also a good thing it is monsoon season here at the moment, as it may have proven to be my undoing as I was planning on taking a tour on the old girl.  DonG

[canuck750]

WTF Indeed!!

imagine if it was winter, the shop heater running and Kaboom!

[Don G]

Yeah, its a little unsettling to say the least, so many bad scenarios ....  DonG

[RinkRat II]

       Glad you caught it when you did. It wasn't the teflons fault. Looks to be a bad casting and the vibrations from use finished it off. After almost 40 years of installing fittings, valves and tubing , the only thing you don't want to use teflon tape on is cast iron. Paste teflon or laco slic tite is the best.

       Paul B

[Don G]

I don't think vibration had a hand in this failure, that cock was installed last winter and has had maybe 50 miles use since then. It just popped apart due to strain I would imagine.  DonG

[normzone]

That's a great story and picture, nonetheless.

Thank you very much.

[Antietam Classic Cycle]

Never seen one fracture like that, threads strip well in advance of that happening. Not a casting - completely machined part. Not a "short cut" in the design either - yes, it's fiddly to get them pointed the desired direction, but it good solid engineering IMO.

[sign216]

I use teflon tape on these threads, but perhaps teflon paste is just as slick.  Perhaps a less slippery sealer, like Hylomar or gasket sealant.

Open to ideas. 

Joe

[Antietam Classic Cycle]

I use teflon tape on these threads, but perhaps teflon paste is just as slick.  Perhaps a less slippery sealer, like Hylomar or gasket sealant.

Open to ideas. 

Joe

I've always used a light application of Permatex 300/Aviation on the threads.

[TimmyTheHog]

geez...glad you caught it in time or the next post would be something really different...

[sign216]

I've always used a light application of Permatex 300/Aviation on the threads.

Known to smallblock owners.  It is The Sealer that Richardson in Guzziology says works best in cyl base oil leaks.

Joe

[guzzisteve]

I have some flipper ones, 3 sets, but I wouldn't use them. They leak. The newer models are put in as designed w/red crush washers and work perfect as designed.   It all works if you do it their way.
I have seen what you have before. That was from age and rust though. Got a whole bag of different sized red fibers.
Hell of a catch. Surprized you didn't smell the fuel.

[Chuck in Indiana]

If I was home, I'd show you a picture of what happens when something fuel related breaks on the road..

[John A]

If I was home, I'd show you a picture of what happens when something fuel related breaks on the road..

Get out your "ball of flames" checklist

[Don G]

It wasn't a catch, and there was nothing to smell. I was in the garage working on another and this just occurred, there it was pissing high test with wild abandon. lucky it wasn't on the road at speed, that is what make it frightening.  DonG

[80CX100]

 Had a recent conversation with my brother (mechanic) about similar issues with many different items, parts & fastenings and the high rate of failure due to poor quality of material, steel, aluminum etc since they introduced recycled metals into the manufacturing process in mid 2000's?

 He theorizes that many of the deadly accidents involving wheels coming off of transport trucks are crappy wheel studs breaking; he might have a point, I've never come closes to breaking a wheel stud in 40 yrs, broke one last fall, snapped like it was made of chalk, when I changed winter tires on my 2010 Rav4, wtf.

 I know the base metal quality, finish and apparent strength on my 2 vintage guzzis appears much higher to me than the 2 more modern bikes, and new replacement parts imho, fwiw.

 Very lucky that your petcock failed where and when it did; for future leaking, I've used yellow sealing teflon tape that is supposed to be fuel resistant as well as "seal all"

  Kelly

 

[Dave Swanson]

FYI, John Chicoine does a great job of restoring the OEM cubes.  I just had him do a pair.  Great work. 

[Kiwi_Roy]

FYI, John Chicoine does a great job of restoring the OEM cubes.  I just had him do a pair.  Great work.

He will sell you a kit with a range of different thickness washers.
I believe Teflon tape is for tapered threads, not the parallel variety.

[sign216]

I had something similar happen when I was a student.  I bought my first motorcycle, an non-running Honda 175 twin.  I and my roommates pushed it up the stairs to my 2nd floor bedroom, where I worked on it.  One night the tank crossover line broke, dumping gallons of old gas all over my bedroom rug.  I woke up that morning to the stench of gasoline.

To this day I'm thankful I didn't die from it, or in a blaze.