Newbie;Jet and Pinasco 177 setup for PX 150

I riding two years on a stock 2005 PX 150 with a Sito plus that is mint and has about 20k km. I did the unthinkable and ran out of two stroke oil. Now I have an excuse to install a bolt on kit, I have decided on a Pinasco 177 Au cylinder kit. I chose this kit because of its reputable high quality, reliability and longevity for every day riding. I am interested in optimizing the mostly used low-mid power range band for city traffic and steep hills. Also, I want a bit more on top end and to be able to cruise at 100km/hr with no issues in overheating. Previously, I have installed a Sito plus and install a 102 in the stock SI 20/20. I am a big boy at 155kg so cruising at 100km/hr was not feasible, however I was satisfied with it mid range torque and power for city riding.

My set up to be for now?  Pinasco 177 Au cylinder kit on a stock motor, 20/20 SI carburetor and a Sito plus exhaust. At this point I have no interest in machining, and modifying other than bolt on. I look every where on the net and I can't get info on proper jet size. Also, I am new to Vespa so any information and advice on a better and balance set up will be greatly appreciated; just remember my criteria, I am only interested in the best bolt on only, for every day riding.

Than you and Best regards

Thanks LaRocca for your reply


I get an impression that no one uses or retains the stock SI 20/20 oil injector, even for the mild basic bolt on only cylinder kit and Sito Plus exhaust. I believe with the right jet size, it can be safely used. Also, I like to take the step by step process and experience, gain and learn from each stage. I will eventually install a 24/24 on my motor and possibly, if I can find one, a better exhaust than a Sito plus that is design for greater torque and a wide power band , not just for top speed only.  From the Official Pinasco site shows a 2% mixture, 20 degree advance, NKG B9 plugs; So many internet posting contradiction compare to the manufactor. However the official site data does not state what carb was used nor the jet size or exhaust. Hmmm, I will be recieving my shipment next week and hopefully there is some recommended factory information for my setup. Otherwise a long distance call to Pinasco. This uncertainally is getting frustrating and I am not into buying another replacement kit.


Best regards

Thanks mchabot for your input. How in theory and in practise does a 24/24 run cooler than a 20/20? Is running cooler is the real benifit with a larger carb setup for my application? How much performance am I to expect?


Best regards

hi dude ...

the engine with the 24 carb runs cooler because you got more fuel oil mix, its essential for a 2 stroke engine because the oil fuel mix is also your engine cooling in association with your air cooling from the flywheel ...


PS: another solution for more tourqe regarding the exhaust is the SIP T5 Pipe




Hello, running the 20 mm si causes the pinasco 177 to get a whole lot hotter then with the 24 mm si.

I have a 177 alu. pinasco with a 24 mm si with standard jetting, and opened both holes in the airfilter underside (above the two jets) sparkplug ngk  b9hs, also a pep exhaust. and motul synthetic 2 stroke oil pre-mixed.





  I have recieved an email from Pinasco regarding my SI 20/20 carb set up for the Pinasco 177 Au kit, stock 2005 PX 150 and uprade Sito plus exhaust. This is what they advised.


   Regarding the setting, we suggest using an atomizer BE3-160 and a main jet 108-110-112-114; the carburation depends on altitude. if you don’t find these components, you can buy our carburation kit 10293000 from your supplier or internet.[Y]


  Matching and Balance is an Engineering Art, Best regards, rudy812

hi ...

the Pinasco 177 is a good idea , but also the dr 177 is good

a very important thing is to use the 24 carb. SI from the PX200 otherwise you risk a damage !

is your px auto oil mix? if yes please think about to mix by your self because with increasing torque you risk that in hi refs your oilpump dont mix the oil and gas in the right way!

if you use the auto oil mix fill some oil in the gas tank to !


with the right setup 177 dr or pinasco right carburetor and jets your ride will run a long time !



Hey LaRocca

    OK, I get it now. SI 20/20 will work but will run the risk of overheating, siezure and buying another kit. So after the upjet, the solution, with running a SI 20/20, is to add more oil in the tank for better engine cooling and lube; or the best solution, as you recomended, is to upgrade to a SI 24/24.


    Brain Storming: Just on cooling effect factor, if I understand this correctly, an oversize carb for my basic setup, for example a 26/26 or more, there will be no greater effect on cooling because the engine does not create enough heat; and more smoke and unburnt fumes will come out of the exhaust.


SIP T5 exhaust, I need more info before I purchase and install one.


Matching and Balance is an Engineering Art


Best Regards