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I bought a PX125 on Friday. E reg 8400 ish on the clock. My dad originally bought it in 1994 and then sold it to his best mate in 1997. It's been garaged for about the last three years and not used. The differences in mileage on the MOT certificates are amusingly small!

Anyway, it's not running properly and we're stumped. It only starts and runs on the choke. As soon as we take it off choke and let it idle, it cuts out. Annoyingly, it was left in the garage with fuel in, which I've been told will probably have gone bad and potentially blocked things up. So far, we've removed and cleaned the carb and jets with compressed air but this only made a very slight improvement. We've also tried a few brand new spark plugs but the engine still doesn't tick over with the choke off.

Another problem it has is with the fuel tap, which appears to be ineffective - as in the fuel is always on.

If anyone can point us in the right direction I'd be most happy

Seal?

Which seal? You'll have to be a bit more specific coz I will have to relay any info to my dad who knows infinitely more about this kind of thing than I do

Crayfish,

Have you tried to set the mixture screws back to factory settings (scooterhelp has this info I keep forgetting ), The oil seal may have perished, to check this drop some oil out of the engine and check if it smells of petrol, if so its knackered and will have to be replaced, if the petrol is permanently on this is not good and you will need to fix that too!

let me know how you get on.

Chip

Crayfish wrote:Which seal? You'll have to be a bit more specific coz I will have to relay any info to my dad who knows infinitely more about this kind of thing than I do

Clutch side seal which involves a complete engine strip and rebuild, but saying that it stood for 3 yrs it would have needed it anyway so best too get all the seals n bearings for the job, the old petrol in the carb would have gummed up as well and compressed air is not good enough too shift it I believe ultrasonic cleaning works wonders but don't know if it's cost effective on the price of a new carb

Cool. We know someone who could do the ultrasonic cleaning as a favour, so that's no problem. I caught my dad perusing the Haynes manual this morning and he said he'd probably have to take the engine apart to get to the seals.

Thanks for the replies

Dont think its seals..and 3 years standing in a garage does NOT mean it needs seals and bearings. Clean carb. Blow through all airways in carb, or try a spare carb.
Seal gone symptoms
Clutch side= Bike will usually run with choke on,gearbox oil will be contaminated with petrol, the bike will often rev itself up before dying when you turn choke off.
Flywheel side....high tickover.

A way to prove beyond all doubt if its the clutch side seal or not is to block the clutch breather, or reove it and replace with a bolt. If this cures it, its the seal. If not, it almost certianly isnt.

Cool beans! Thanks for all the info.

Might go quiet for a few days while we work on some stuff.

News!

Since my last post we ordered another carb from ebay 2nd hand but from a running bike and much cleaner than the original And for £12 delivered, if it fixed it then all would've been well. My dad fitted it for me on Friday and the engine ran without choke but it still wasn't right. It still revved on by itself a bit and when we took the engine off, one side of the casing was stained a bit with fuel. Luckily, we've found a Vespa guy nearby and we're sending the engine to him this week for whatever's needed to get it right. While that's away we'll fit the new fuel tap we got from him the other week.

Hopefully I'll be able to update again next weekend.

It's working! IT'S WORKING!!!

The engine has had new seals, cruciform, gaskets and whatever else was deemed needed and my dad's had it running like clockwork today

Thanks to everyone for the advice. Now the real fun begins!

Happy Days