Vespa non starter


I need some help. My little brother has just bought a non-runner Vespa PK125 Auto. It has been standing for about 4 months. I have tried to start it but have had no luck yet. The sparkplug is sparking and is wet with petrol. I was told that the exhaust was blocked, so i have disconnected the exhaust for the time being, just to try and start it. The engine trys a little to start, but only a couple of fires. I took the head off and gave it a good clean. The plug is new. I think that this model has electronic ignition so I am wondering wether i need to look at this for a fault. what do you think ? Should I whip the carb off and check the jets/float bowl ?

Any help would be very very much appreciated.



Hi peter fly wheel holding tool £6.50 Fly wheel puller £3.99 not going to brake the bank new fly wheel costs a lot more realy the best way to hold and remove the flywheel not very long job can get them from any good uk shop beedspeed tafspeed hope thi helps Gary[:dance1:] [:dance3:]

How is the compression? Another thing to check when a vespa has been sat for a long time is the oil seals. Both mine went after the scoot was in the shed for 6 months.


Thanks for the reply.

If the stator had moved would’nt the bike at least try and fire a little ?

I think you are right, and the carb is the problem here. The bike was standing for about 4 months when we picked it up. So maybe things have got bunged up or something.

I will let you know how i get on.



Watcha everone,

OK may have sorted out the problem !

Took off the flywheel cover and guess what ?..No woodruff key holding the flywheel in place !!!

As you can imagine the flywheel was just spinning around going in and out of the correct timing position.

Got a woodruff key tomoz …will fit it and see what happens.

Thing that should do the trick.

Thanks for all the advice.



[:bounce:] [:bounce:] [:bounce:] [:bounce:]

Right mate then if your head was covered in black oily stuff (quite thick yes?) and the plug was covered in the same then you clutch side oil seal is away. this means a full strip and rebuild job. the clutch side seal is what holds the gearbox oil out of the rotary injection system (the crank and piston) and if it is away it will flood through into the crank case and stop the engine from running cos it will mix with the petrol and make a pretty much in flammable mixture so it might fire now and again but in general it will be a dead duck. Now that you have described the situation i can pretty much put every penny i have on it being a burst clutch side oil seal.
Unlucky mate, hope you get on OK, get in touch and let me know if i’m right.

Email me on [email protected] if you have any other questions cos i have shit loads of experience with the hateful little PK.[:smokin:] [:drink:]

Watcha Screamin_demon,

Will have a look at it tonight mate. Not sure what its set on at the mo. What would be a good starting(no pun intended) point to put in on ?



I would try cleaning the carb. In my experience of CDI’s if you look at the spark plug and its firing consistently the CDI is ok. On the 2 CDI’s that I have had go down, one would not spark at all and the other sparked only ocassionally. You could take off the flywheel to see if the stator has moved.


Compression is fine - I think !

With the plug out, seems to produce quite a good b*** !!! and is quite hard to kick overwhen its in (is it a high compression engine ?

I am going to whip the carb out tomoz and see what is going on there.

Someone was telling me that two strokes need crankcase pressure to suck the petrol from the carb. Is that were you are going with the oil seals ? Being new to scotters myself I havent really much of a clue.



Watcha Guys,

OK, the scoot is not an auto ! After thinking about what you guys all said ,and looking at the bike a bit more closley, it is obvious that it is a manual change. (how stupid do i feel !).

Anyway, I still cant get the bugger to start. I have stripped the carb down and cleaned out all the jets/float etc. I emptied out the petrol and put fresh in. Kicked it over a few times and it fired a bit. Tried to bump start it …no good. After all of this i took the plug out and it was well black. Oily as well ! what does that mean ? I also took the head off and that had loads of this black oily stuff on it a swell ! So i went further and took the barrell off to check out the piston rings etc. Everything looked ok (i think !). There was a lot of this black oily stuff on the outside of the barrell as well, so i assume that the gasket was not a good seal.

Anyone one got any suggestions(keep em clean please ! )

Timing ? I know its electronic, but spose it could be out eh ? Anyone got any tips about getting the cover out without a hub puller or whatever you need ?

Cheers for any help.


i would have to agree with just about everyone that has replied, give the carb a good clean out and try it, if that doesn’t do it then take out the plug and check to see if the spark is regular or irregular, if it is irregular then i would definatley consider changing stator plates, i could aslo be the coil, but then it could also be so many other things. However i would reconnect the exhaust as it could also stop it from running. Have you taken the whole barrel off to check the piston rings or for wear in the barrel. I have just finished rebuilding one of these scooters and they are without doubt the most endless model vespa ever released. but check the rings the barrel the stator and the coil for starters and of course clean out the carb. if none of these things help to sort out the problem then i would look at perhaps the clutch side oil seal being burst or worst case scenario the crank being twisted. oh and reconnect that exhaust as it is very unlikely that that will stop it from running, usually a blocked exhaust only affects a bike whilst it is on the move.

good luck!!![:)]

Wahoo, it works, it works, it works !!!

bunged the new woodruff key in(after digging out the remains of the old one from the groove in the shaft…their was a small bit missing !) put the flywheel back, and bingo, first kick and that puppy started up and sounded so sweet man.

Thanks for all the advice.

Pete[:smile:] [:dance1:] [:bounce:] [:D] ;D [:rotate:] [:look:]