Motorcycle and Scooter appreciation

Why not get a mate to hold the front down then ;)

The only person available would be Mrs Sparky, and her contempt for helping with manual tasks is matched only by her clumsiness in seeing them through.

Milk crate:

+1, every mechanic should have a milk crate.

and dungarees

Was on my way to Gravesend today to see the Vulcan's final flypast when I had some bother.

Was going 50mph down the A2 when suddenly my engine bogged and I started engine-braking quite hard. I popped the clutch in and got over to the hard shoulder and there was a funny burning smell. Started back up but it wouldn't idle, just cut out after a few seconds.

I nearly had a heart attack when it first happened.

Eventually I limped it off the main road and let it cool down. Now, I'd run my tank almost empty just before, and I think some crud may have clogged a jet or something.

Once I got it going again it behaved itself and I felt like I'd dislodged whatever the culprit was. Missed the flypast but had a pootle around for the afternoon anyway.

Anything to worry about, or just a blip?

Stick a fuel filter inline.

Did it do it again? Did it feel like fuel starvation?

In irrelavant news I have been given a px125 wheel with a barely legal pirelli tyre 3mm maybe so if anyone needs a spare...

Not sure what it felt like. Scary. Posted same thing on a Vespa forum and they're telling me to inspect the cylinder walls for scoring before I ride it again. Which is a pain I don't need.

If it was my (elderly) moped it would be sludge or rust particles in the float chamber causing the float to stick with resulting fuel starvation. It does it every now and then because the Amal in-line filter (alloy body, nylon mesh) looks the part but is little more than a strainer: something less period and more effective (with a transparent body and paper element) is needed at some point.
It might be just a blip but it's probably worth looking into - clean the outside of the carb first, have the jets out and remove the top of the float chamber - large particles making their way into the combustion chamber are a bad thing, so if you find anything at all it's definitely time to fit a (better) filter. Hot spots, pre-ignition, holed piston and broken rings are possibilities as well as a scored bore...

I had one of those filters too, has it got a block of metal mesh. If so it is not a good filter.

Excuse to buy an endoscope/boroscope?

I don't think it's actually that hard to get the cylinder head off on a Vespa. Quite what I'm looking for once I'm in there is a bit of a mystery, though.

If I don't see any scoring I guess I'm ok. Otherwise...

some geezer in a white Audi faux by four had a right go at me this morning, all because he flashed me to go across him at a junction, but I gestured for him to go around the back of me, as he should - I couldn't see what might be coming straight across behind him because his ugly shit car was blocking my view - just trying to stay alive pal

Me and Mrs Sparky drove into Brixton last night for a Doug Stanhope gig (lazy, I know, but we're in a public transport black hole and getting 4 miles to Brixton takes an hour and a half, and Mrs Sparky won't ride at night). The standard of driving was staggering. Bonkers. And then a bloke on a scrambler with no lights, number plate or indicators roared past. No helmet, wearing a balaclava. Brixton....

We have that in suburban Birmingham - a guy across the road has a legit ktm motorbike he rides to work (and tunes up everyday for about 4 hours) but at nights there are scramblers and quads hanging out there, then they all dress in black, pop on scarves and hoods up, off over parks down the cyclepaths. three or four bikes, no lights or numberplates, no helmets but go-pros attached to the bikes! Sick wheelies.

It's a piece of piss but make sure you torque down the cylinder head correctly and evenly after, I didn't do that once and it ran like shit until someone who knew what they were talking about sorted it out for me

squish?

What am I looking for while I'm in there? Just scoring on the cylinder walls or any obvious damage? If there isn't any, what's to stop it happening again? Is that where the fuel filter comes in? Does that sound like the likely culprit?

If I do see damage then I may just have a little cry and wheel it out on to the street with a sign saying "Free Vespa (warning, it's a total lemon)."

Oh that's a bit beyond my spanner level, and I only know smallframe engines, but if the worst came to the worst the kit to replace the barrel etc is pretty cheap

Damn it. The temptation to buy a new plastic scooter is strong.

Sorry mate - does sound a lot like it nipped up (seized.) not at all familiar with the engine arrangements on scooters but can you not just drop the exhaust off and stick a flashlight down the exhaust ports?

Top end rebuilds are a doddle on 2 strokes and usually pretty cheap. I wouldn't ride it any more until I'd checked it though....

OK. Thanks all. May pop the top off and take some pics, post them here, see what people think.

I'd still look at the carb first - quicker and easier, fewer gaskets, fewer tools, and if you find sludge or rust particles you've probably nailed the cause. Removing the head would be next (assuming you can't see anything through the plug hole or exhaust port) knowing what you find will be more likely to be symptoms than a cause.
http://www.smellofdeath.com/lloydy/piston_diag_guide.htm and similar (I know, not a Vespa, but similar engineering) might help when peering down dark holes?
You can always blame the ethanol - it used to be quite the thing on NACC runs to blame E5 for all forms of breakdown...

Yeah definitely check the carb - running lean is the number one enemy for 2 strokes. I would still pull the head / exhaust off before you run it again. You mentioned heavy engine braking - that sounds like a partial seize. Often they'll run after that but you're risking dumping bits of piston skirt in the bottom end and trashing the crank / mains and that's full rebuild time.

I used to strip and rebuild my TZR250 by flashlight overnight then off to work the next morning. 2 strokes, you've got to love 'em. Always have a spare barrel and matching piston to hand, or 2 if it's a twin. You shouldn't be shy of whipping the head off anyway, just tighten the bolts diagonally opposite each other when you put it back on, if you've not got a torque wrench just be sensible and use a 6-10inch ratchet. Most 2 strokes you'll get away without a tool for the rings. If you take the piston off, you'll probably want a new gudgeon pin circlips though.