Hi All

Thought i would consult the font of knowledge that is LCB with my scooter issue.

Bought a 50cc peugeot speedfight scooter for the stepson last week cheap as chips as it was sold as a non runner. The battery was flat and it wouldnt start with a jump. These bikes have issues with the immobiliser which is built into the CDI so I purchased a bypass CDI without the Immobiliser.

That arrived this morning so fitted it along with a new coil, lead and plug. Bike started first go but was lumpy and (blue) smoky. turned it off and drained the old fuel out, took the carb apart and cleaned it all up. Tried again with fresh fuel and it started but then died and wouldn't start again.

Its getting spark. Its getting fuel as when opening the drain on the bowl there is fresh fuel. I did a compression test and its holding 8.5 bar. Pulled the head off and the piston/rings/barrel all look good (bike only done 5k). The only definitive fault I have managed to find is the oil pump doesnt seem to be pumping oil to the carb. There is oil getting to the pump, ive bled it but there is nothing from the outlet to the carb.

I have a new pump on order but my question is would no oil in the mix stop it starting?

cheers
Steve

Are you 100% it's not pumping? I was testing an old 200c twin Yamaha today and at cranking speeds (with plugs out) it pumped very slowly, took a couple of minutes to fill the pipe from pump to carb, initially I didn't think it was working.

I would have thought it would have seized if it hadn't been pumping and you wouldn't have gotten such a good compression test.

Cheers
Davie

99% certain. There was no oil residue at the carb when I took the tube off after 5 mins running at idle. The pump is a mechanical drive one and I used a cordless drill to drive it at a sensible speed and there was nothing coming out of the outlet at all. I stripped pump down as far as possible but couldnt really see much.

I was wondering if the previous owner knew about this and was premixing the fuel thats why it ran ok ish before I drained it?

Yup I agree, can't really add anything useful sorry.

Cheers
Davie

No it will still start without oil pump working
Try heating a plug, and dropping it back in quick
I wouldn't worry about the smoke yet if its been standing or if its been run on petroil mix because the pumps not working!

I think Id look at the carb again

Clean the primary jet well, it probably ran till the electric choke cut off then stopped.

Well I've had the carb apart again and it's clean as a whistle blew all the jets through again and put it back together. I also tested the auto choke and that is working fine. I am waiting on the new oil pump and head gaskets arriving and will hopefully give it another go midweek.

Cheers
Steve

I presume you mean the two stoke oil pump ?

As if that is not working, as was on an old suzuli year ago, i just added 2 stroke oil in the tank,
cant remember how much, but 10 fuel to one oil would probably be sufficent

Yeah that's the one. If it was me riding it I would just mix it myself but as its for a 16 year-old I would prefer to have the pump working.

just a thought

when our kids 50cc 4 stroke has been standing for a while i have to take the vaccum pipe of the intake and suck it so the fuel valve opens and allows fuel through.

could it be that there is a vaccum leak and so valves are not opening?

ditch

Yes it does have a diaphragm type fuel tap but it is working. I'm convinced it's been running premixed oil/fuel and when I've put in fresh petrol it's flooded it. We will see when my bits arrive. Was quite refreshing to remove a cylinder head in 5 mins flat! Tinkering with this has also help alleviate my post build blues

Well if it runs ok on the mix of petrol and oil you know it's the pump (or associated part)