Modern Vespa

On my way home tonight I noticed my LX get very loud. I have attached video of my accelerating when I got home to show an example of the sound. The bike rides fine, with no power loss or anything but I have noticed the bikes sound changed over the last few weeks, but the sound changed all of a sudden on the way home. I cannot locate any holes or damage to the exhaust at all. I did fill with fuel this morning and am wondering if this could be a dodgy mix at the fuel station?

The video can be viewed via this dropbox link: -

https://www.dropbox.com/s/kxdsqkluaj55ce3/Video%2029-04-2014%2018%2049%2033.mov

Sounds like a rattle, heat shield all tight?

I'm wondering if the hub oil is low?

Have you checked?

Yes and it's just above the first marker, close to half way between the first and the second. I believe the second is the maximum?

Not 100% sure of the markings for your bike but I reckon you have above the min. Is that shield on tight on the exhaust?

Not seeing the link between low hub oil and your suddenly noisy scoot. Or did you mean in addition to?

Heat shield is fine, it's defo mechanical loudness.

I thought that low hub oil may affect the gears and create a nosier acceleration sound?

TheKarateKid, does it sound like the exhaust note is louder or are you hearing a rattle?

Check the exhaust for cracks, and check it is firmly attached at the head - i.e. no loose or sheared studs. If that all OK then some of the 'convolutions' inside the exhaust may have corroded away, and it's become more of a 'straight pipe' that it was originally designed to be.

It's sound like the exhaust is much louder

I agree - so as above. If it wasn't a one-piece exhaust I'd be saying check the exhaust gasket - but as that's not the case you're left with the innards of the exhaust, its connection to the engine, or a hole in it somewhere that's blowing.

[quote="TheKarateKid"] Going to get this looked at won't happen until the weekend, but I need my vespa for work. Is it likely to cause serious damage?

Would even the tiniest hole cause this ?

Yes, a tiny hole will make it sound a lot louder. No harm should come from a small hole - but if the joint to the engine is awry then nasty things could happen to any lines nearby, or even to the exhaust valves if it gets really loose.

I did check the exhaust and it seems pretty solid and not lose, however I was able to scrape off a lot of surface rust. This is the exhaust it has:-

https://www.google.co.uk/search?q=vespa+lx+exhaust&client=safari&hl=en-gb&source=lnms&tbm=isch&sa=X&ei=_CFgU4idAsrYPZCYgfgG&ved=0CAcQ_AUoAQ&biw=320&bih=460#facrc=_&imgrc=4RZ7qELYPWzkCM%253A%3BaNMuwsT1xTpG3M%3Bhttp%253A%252F%252Fwww.scooterworks.com%252Ffilebin%252Fimages%252Fproducts%252F1000%252F0500-1061_1000.jpg%3Bhttp%253A%252F%252Fwww.scooterworks.com%252Fsito-plus-exhaust--vespa-lx-150-ie-products-12476.php%3B1000%3B1000

Then I'd suspect something come adrift or been holed inside it.

Swap with a friend's known good exhaust to test.

TKK,
Yours sounds just like mine did when the exhaust gasket came loose.

Knowing you don't have one makes it more curious.

As jimc says, most likely something inside the exhaust system itself.

Could it be a lose exhaust emissions adjustment. But as shown in this picture (3) or a lose pipe at the tail end?

Is this the 2-stroke version? If not, I bet there are people that would pay for their exhaust to sound like that

A complete newbie and with little knowledge. But on a Kymco like a similar sound resulted from one of the rubber grommet being lost on one of the kick stand. But again, that was a kymco.

Possible, but it's been my experience that it'll most likely be near where something attaches. There may be a gasket or similar where the pipe attaches to the head. The picture doesn't show one, but I'm assuming there's something there. It could be leaking even though the bolts are tight.

Otherwise, it's what you said or something loose or perforated inside the pipe.