Modern Vespa

That's a very helpful tidbit. Thanks, Mesmer.

Yeah, me either.

Yes. Mine Were OEM bolts with an OEM exhaust.

Except yours was welded as a one-piece...

That is only the header piper where it feeds into the sleeve clamp. The bolts at the back have nothing to do with the fact that it was welded further up the line.

Without the graphite collar to allow the header pipe to move in relation to the exhaust itself, there must have been extra stresses and therefore strains - whether these are enough to help dislodge the bolts who knows.

Except I had one bolt back out on me BEFORE I welded my pipe, and one after.

And yes... Who knows...

Now you guys made me go out and check my muffler!! It is OEM, has just over 16,000 miles, the Moto Amore "muffler bearing", a touch of antiseize on each OEM bolt and all 3 were tight as can be. The muffler has been removed and refitted probably 6 times so far, the last 5 times split at the muffler bearing location leaving the header pipe alone. That is a really strange phenomina. Does anyone know if the GT250 uses the same OEM bolt with a torque head as the GT200 OEM hex head bolt? Possibly a slight difference in the stainless steel thread? The mystery continues.

You all have come up with a variety of esoteric possibilities, but usually the simplest one is the right one:

Somebody took the bolts out ("screwing with him"?)

GT and GTS do not use the same bolts, at least in the US. The heads on the GTS bolts are torx, on the GT they're just hex.

TheOZ: I know that one is a hex head and the other is a torx head but what I was asking is are the bolts the same other than the heads or are they a different size or length or different threads? It sort of makes one wonder why they changed to a torx head on the GT250. Just curious.

O.K...thru all of these posts...I'm going to check out my exhaust and make sure it's secure...thanks!

But just one minute..the theft thing still sticks in my mind...two reasons:

1. Son had the lugs from his mags on his former car loosen when he got back to drive home...yes it was that noticeable! We called the police just to file a report and they told us the MO would be for one member of the theft team would walk by or just drive by and pick his target. Would then loosen the lugs...this was followed by someone coming by in a truck and quick as possible get it up on cinder blocks and load and drive off.

2. Related to #1...I've read that catalytic convertors are being ripped off and sold to scrap yards for the platinum found in the cc's.

Per #1 and #2...that exhaust could have been destined to a scrap dealer per a theft ring that knows there's some value to either the exhaust or material therein. Then again...there are those darn exterrestrial types running around with nothing better to do...

Mig...to you I give a lot of credit in keeping a postive attitude and yes, the worst part was getting inconvenience...however, you had a good buddy to help you out...I am fortunate to have the same. O.K. now with that being said...tell me is the noise level LOUD?...I mean can you go around and cozy up to those HD guys and join in?

ah, oops. Sorry.

I think it's just the heads, if I recall correctly. And ironically, I believe the reason for it was to deter theft, or so goes the old wive's tale.

I had the same problem last year. In my case, the upper rear bolt was gone and the lower bolt was loose. Only the front
upper bolt was snug. I had been hearing a rattling noise and (fortunately) found the cause before the muffler fell off.

-David

The only one I have ever seen out of 1000's was one 07 GT200 that a client of ours whomped a pothole at 80 on the freeway, it sheared the bolts on the swingarm and exhaust. Pretty violent situation obviously however he kept it upright (brilliant) and to a stop. I have never seen or heard of them just "backing out" which leads me to agree with those suspicious of either tampering or theory B which was walking away from a task unfinished, which certainly can happen, we are all human you know.

Nobody got hurt, bike can be fixed, I say we are all good on this one.

SDG

Once I had the steering wheel come off in my hands while traveling merrily along @ 70mph. This was on a Volvo 122 (pre-ol Yeller). Someone had forgotten to replace the locking washer. Thank goddess the wheels were in good alignment.

But that wasn't nearly as exciting as the time a Saab 96 V-4 engine burst into flames while, again, traveling merrily along @ 70 mph.

Good times.

\\osc

Oh, right -- the exhaust fell off the Rally once. Does that count?

Why did half a Mod Rondel suddenly appear under my avatar? Sorry, didn't get the memo.

Do I have half good or bad karma? Only half 'cause I ride motos & scooters? Cause I mentioned a cage above???

Normally I am a Rondel-half-full kinda guy, but feel something is missing.

Okay, just to clarify some things further:

--I didn't ride over or hit anything like a pothole.
--I noticed no noise before it happened, e.g. "something seems to be coming loose and rattling" type of noise.
--The play-by-play, as best I can recall (it happened in a matter of a few seconds, and the adrenaline kicked in immediately):
I was riding normally (probably about 70-75mph) at the end of the day. Had been riding all day and it was bliss. Suddenly I *felt* it... it wasn't like a loud "bang" but I suddenly *felt* something, as if something had just suddenly come off. I looked down and saw Some Big Black Chunk (later identified as the entire exhaust assembly) come off, and everything was suddenly rickety and LOUD.
My immediate thought was actually that I'd blown the front tire, and so the high school driver's ed instinct kicked in: "try to let the car (scooter) come to a stop on its own while you gently steer it to the shoulder, applying the brake verrrrry gently." So that's what I did.

I'm still baffled even after reading all the thoughts on this thread. I don't suspect foul play, but if it was, then HA HA, CHUMPS, I LIVE ON!

Just the entire muffler, not the whole system. Damn thing went bouncing down Highway 75 a few miles north of Pipestone, Minnesota.

It was 1966....and the bike was a 1955 Zundapp 250, a two stroke single. My dad bought it for me for $50 or $75, don't remember which. Sometimes it ran.

A highway patrolman stopped on the shoulder behind me as I was trying to 'jerry-rig' the exhaust can back on the bike.

Got my first ticket that day. I only had a 'learner's permit' and wasn't supposed to be driving or riding anything without a parent or licensed, adult driver along in the vehicle.

Sorry for the long story, but you asked.

mig...someone is watching over you...I mean this sincerely...for our Family...it's my late Mom... Thanks for answering my question...LOUD...be safe!

What direction did you park it in, in relation to the rotation of the planet?

Park it the wrong way for too long and the nuts will rotate themselves right off.

It's a good plan to park it facing uphill so all the starts don't fall out too.

/nods

I've had mine welded (header to exhaust) for over 30k now and the bolts are always tight. Did replace the stock star bolts (or whatever you call them) with real bolts that have 13mm heads.

The same thing just happened to me not 20 minutes ago. Newish 2012 300 Super Sport with a bolt-on Leo Vince exhaust that was installed by the dealer. It had the run-in and one regular service under it's belt. Everything looked solid on the exhaust assembly the last time I washed it (a little over a week ago) and while I didn't check the bolts with a torque meter, I did make sure they weren't backing out or had any visual signs of stress. Nothing looked out of place when I gave the bike a walk-around pre-ride, either.

I was on Houston's 610 loop, doing a hair under 80, on a newly repaired piece of freeway (smooth - no bumps), when I started to change lanes to my right. I had passed an 18 wheeler and had just pulled into his lane about 20 meters in front of him when I thought he laid into his air horn. It was super loud and it sounded like he was 2 feet in back of me, not 20 meters. Either that or the Miata to my right had some sort of train horn installed and had decided to give me a sustained warning blast to make sure I didn't come into his lane. Either option was unnecessary and extremely annoying. A half second later, I realized what had actually happened.

I got off the freeway at the next exit to verify and the entire pipe was gone. Two top bolts are completely missing and two bottom bolts are still holding the remaining tabs of the exhaust mounts. Not quite the same scenario, but still more than a little mysterious.

I circled back to try to find my exhaust and clear it from the road, but it had already been pummeled and pushed over against the barrier on the inside lane. I'll try to go back for it tonight, when I just have to contend with sport bikes coming around the bend at 120 instead of a thick stream of traffic at 70.

My Super now sounds like a combination MotoGP/trials bike. If loud pipes really do save lives, then I was the most saved individual on all of MV for the five minutes it took to complete my ride home.

That's rad! Well, I mean, that's really a bummer, but kind of cool in its unusualness.

Could be road gremlins. Nasty little devils. They do have a wicked twisted sense of humor. Do have a gremlin (rider) bell attached to the undercarriage of your scooter?

No bell on this one, which could be half of the problem. The other part of the equation was me thinking, "I don't usually push 80 wearing jeans. I hope nothing bad happens..."

I knew there was a perfectly valid scientific explanation buried in there somewhere.

So you definitely haven't just dumped your girlfriend or pissed off a mate?

Food for thought we are not allowed to use lock washers at my workplace and they define the purpose of lock washers as "assists the technician to remove hardware." We have to use lock nuts or thread-locker.

Sounds completely wrong, but all of our hardware comes with certifications of quality so I go with it. Plus if you think about it, a lock washer is only effective for the first couple turns anyway.

I don't work for a hole in the wall shop either... 20 million people ride our roller coasters each year.

That's a bit of a distortion of what a lock washer does. The goal of a lock washer is to maintain tension on the threads, and prevent it from turning at all. If it performs its intended task, then it never gets past a couple of turns to begin with, rendering that potential outcome moot. If it does allow the fastener to turn, then it didn't perform its duty.

Nylocks and thread lock are great, and I use them liberally. That said, I don't think we can reasonably disparage lock washers based on the idea that they fail to hold the fastener after they've already failed. The logic of that statement doesn't really pass muster.

I've had 3 screws that were holding my airbox disappear on a ride and it was dangling when i got to where i was going. Bad roads tho. Your roads seem better than ours. Where's Rod Sterling when you need him, besides dead. Hope you find the cause

Those three screws are notorious for disappearing. The kind of lock washer used by the factory for those doesn't work well, but a standard split-ring lock washer is very effective.

A friend had a Scorpion pipe fall off his GTS250.

Broke away from the rear mounting and fell away from the header.

Nice.

Bill x

This literally just happened to my 2016 Vespa sprint 150 abs that I keep in the driveway in front of my house. Except my exhaust didn't completely fall off but it was dragging on the ground and the 2 bolts are missing. I was hearing a vibration noise for a few weeks of riding it which were probably the loose bolts but my dumbass didn't even look or check down there. Lesson learned. Also is it bad to ride without the exhaust completely on? I still have 750 miles left to reach 30K miles and want to get as close to 30K as possible for my next service but for now my exhaust is held on by some rubber thingy ma jigs (I forgot what the technical term for them is) here are the pics for proof!!!

That downpipe is completely cracked open - so there's no point hanging the disconnected exhaust at the side.

It'll be extremely loud - probably illegally so.

achievement unlocked 🏆

It's dead, Jim.

Time for a new exhaust.