Scooterotica

Hi guys, just picked up what i believe to be a 1998 PX125, well thats what i was told it was. Im new to the scene but been rebuilding classic jap bikes for many years, although never a rotary valve motor.

Can anyone help me with the following please, how do i identify the engine i have? (i dont believe its original to the bike and the barrel looks new/aftermarket)

Its on premix, can you recommend a correct 2t mix please

What are the common symptoms of crank seal failure with these? (there is lift on flywheel end, so a rebuild is on order, just be nice to be able to ride it a little to assess if anything else needs attention (clutch, gearbox etc)
its not on the road so hard to tell if its using gearbox oil but it arrived with none in it. Starts first kick without choke, smokes quite heavily for a minute or so whilst spitting back through carb and floods up and dies

Currently waiting on a manual and flywheel puller to arrive, in the mean time i thought i would seek some advice here

Any help much appreciated

First thing to do is get the engine prefix to see what you may have.

2% oil ratio is the norm.

It does sound like the seals are iffy, smoke generally isn't a good sign as you no doubt know from working on bikes.

A couple of sites worth checking out are Scooterhelp and Vespa P range maintainance.

Good luck with it.

Between this and a Haynes manual you can't go far wrong.....

http://www.scooterhelp.com/

Enjoy.

That's great thanks guys, really appreciate your help. I will try and get the engine prefix today.

I've seen several motors with lift on the flywheel which run fine. It's usually a sign of worn bearings though. It's also worth checking if the flywheel moves in and out when you pull the clutch this can also be a sign of a worn clutch side bearing.

Thats a great bit of advice thank you, i will be checking it shortly. Any thoughts on the carb spitting back and flooding? Its cleaned and clear, all gaskets replaced and faces checked for true, no air leaks i can find on the induction side

Engine number as follows, E18 43010018, barrels has the following marks, PAB 2011
Carb is a SL24-24E Jets are 55-160 and 160

Seems to be running way too rich and flooding up, mixture screw right in and it will tick over for a while and rev, anywhere near standard and it dies quickly, tickover screw right in also (checked and both are fine, not damaged)

Also, previous owner has bypassed the fuel tap, this shouldn't affect running but why would this be done, are they prone to blockage or something?

Bypassed the tap? How has that been done?

The 24/24 carb is meant for a 200 motor. It probably too big for a standards 125 and if it's over jetted too, that won't help with the spit back and flooding.

Check also that the float needle actually stops the flow of fuel as if it doesn't this can contribute to flooding.

55/160 is your pilot jet

The 'main jet' is a stack of three parts. The top part is the air corrector (numbered) the middle is the emulsion tube ( should be marked BE and a number) and the bottom bit with the chamfered end is the actual main jet (numbered). All three need to be taken in the round to give an idea what the jetting is properly.

Just reading about the jets now thanks to those previous links, so here is what i have

160 BE3 116

Whipped the head off, its marked 150-s

Barrel is 57.7mm, piston marked 25g13 not had chance to look up the cc yet

But it points to over sized carb at present doesnt it