Primmy engine

Alright all!
After checking out previous threads, and advice from a mate. I’m in need of a primmy 125 engine to slot into my pk50 s, fat bloke on 50 not go very fast!!! Any clues on where i could get one (the words rockinghorse an shit have been mentioned), an if so what sort of amount should i be looking at. Any other advice would be usefull. Cheers![:drink:]

Hi Vespadoc & Slidy.
Had to change names as at the time i couldn’t remember my password for this name ( novista).
Vespadoc, see the setup you’ve suggested would it be a combination of yours an slidy’s?
Cos when i talked to my local scootershop, they said summat about changing the gearing if i was using a kit (please bear with me as i know fuckall).
:stuck_out_tongue: [:drink:]

I’m not an expert!
But if your going to tune it, just keep the pk50 engine, get a crank with a longer stroke so that you can use the barrel off a 90/100/125 or a kit then you can keep all the electrics and four speed, change carb and the clutch/front gear to up gear.
Did this to my brothers small frame but used the 90 flywheel stator a little while ago so might of forgot somthing obvious!
ask here

they are!!! [:D]

that slidy old dog hit the nail on the head!!.do the fifty an example.50 special,24mm delorto carb,polini110 kit and polini exhaust + 15st of ugly fat = 60mph no probs, i know coz its wot i had.revs like a mo-fugga takes px125’s and cheap as chips.primmy motors are a pain to get hold of in uk that arent shagged

stroud valleys(midnight hour)sc est 1984

i used my setup as quoted(pulls like a 2 bit whore) you can change cranks/gears etc but a good starting point without splashing out shed loads of cash but shite loads of power is what i said can change anything else at a later date to alter gearing/stroke etc but if you just want a nippy litty cow to whip about on and pull 60 no probs this isa good starter and a doddle to do.standard 50 special gearing will enable 70mph and i presume its the same as pk50

stroud valleys(midnight hour)sc est 1984

Cheers vespadoc!
Been searching around on the internet for parts, seems like i’m looking at about £150 (your chippy must be in park lane?). polini 112 kit, dellorto carb & leovinchi exhaust, what sort of carb i know the size (19 or 24) but what type (phbl? wots that mean, i now understand as & bs, thanks to the jb website). Well i’m a third of the way there on the cash front, i’ll be back when it’s sorted! Watch this space. Like the idea of the gearing, (jb site advising on a racing crank?). Have a good weekend. [:drink:]

i do like a very very large portion of chips!! thats why i run a 210 to pull my gut its like carrying two passengers.if you only change barrel,exhaust and carb you wont have to split the casings and still get big revs,fitting a race crank to this setup will increase fuel consumption but not performance,more fuel+standard crank= less room for gasses therefore more crank compression to force gas into cylinder.if you try the cheap setup theres always room for improvement late to split casings and gear up,change crank,fully port etc etc.the carb you want is a phb24 and the polini exhaust.with all the bits being polini and well used by me i can vouch for the success of this setup and you can call me susan if it isnt so

stroud valleys(midnight hour)sc est 1984

I think if you change the crank you can then use the 135 kit,as the only diffrence between 50 and the 90/125 was the stroke of the crank, cases were the same? and the barrel spigot is the same size? worth checking as I might be talking shite![:D]