Malossi 166 jetting?


I have fitted a malossi 166 kit on to my PX 125 E (1997) with a Dell’orto SI 24/24 E carb and a Simonini exhaust.
Jetting is currently at:
Main Jet 116
Calibrator BE4
Idle mixture jet 50/120

With this config, i can’t regulate the idle…

Somebody can help me ?

I have just fitted a 166 kit to my PX125 with a scootrs pipe. I’m having problems jetting it. Started off with the 115 jet that came with the kit but this was too large. anything over half throttle and the scoot bogs down. I then tried a 112 and a 109 and the same thing happened. When i put the standard jet back in which is a 96 it runs much better but wont go over about 40mph, im assuming not enough fuel is getting in. Is it just a case of trying every jet until i find the best ?

You don^t specify if you have done the cranckase porting and if you have a race cranck.

Try with :

Main: 120 (bigger if porting done and race cranck)
iddle: 48 160
calibrator BE3
Air corrector 180

It will very probably need to be corrected, but you have to start from somewhere. Then report us what is better or worse and we will try to improve the set up.

…and check if the carb gasket is well on its seat.
Sometimes when fitting the carb the gasket moves, then you push the fitting screw making new holes but the gasket partially block the inlet port giving problems.

Original von trodd: Thanks for your answers...

Indeed, the throttle is completly closed ; so must i tighten the throttlecable to open a little more the throttle ??

no, don’t worry, the idle set screw will adjust it / L

Thanks for your answers…

Indeed, the throttle is completly closed ; so must i tighten the throttlecable to open a little more the throttle ??

I don’t have done the crankase porting and i don’t use a race crankshaft.
After checking, The gasket is well on its seat. So i will try your config.



I too am after some advise on Jetting for  malossi 166 kit, I am currently running on a 24/24 spaco carb, with jetting of 160 air corrector, BE3 Atomizor, and 116 main Jet, my idle Jt is 50-160 and running witha simonini exhuast, I have done the 500 mile bedding in mileage, and now starting to do the 500 mile with a bit more load on the throttle, thing is I notice at a steady 30 mph every so often it seems to jump as though it is a power band, any ideas on the best jetting so that is a smooth all round ride at low and high rev's anyone

don’t know about the jetting, but check if the throttlecable is closing the throttle completly, or if air is leaking between carb & case.


[:dance1:] [:dance1:]

I also have this setup, but the bike splutters when opening past about /8th throttle.

Also is a BE4 richer than a BE3?