Polini 177cc pinking and seize?

Hi !

I have read in this forum that Polini 177cc kit is prone to pinking
and heat seizing. Is it a problem from the manufacture, or is it the users that can not set up the kit right ??
A few have put a gasket at the head to lower compression !!
Isnt that a delicate task that Polinis engineers have taking care of
when they designed the kit, or did the miss something.
What parameters is involved when this problems occur ??
I have build an P150X engine with this kit and a 28mm Dellorto
and a better exhaust than the original.And the jetting is a good setup from Curare [:)] I havent been able to do some extensive testing because of the winter season here. But i have done a few rounds on my parking, and the engine runs and sounds well.
I dont want to ruin my engine if i can, so any input in this matter would be nice.

\Pallla

[:shock1:]

helllo Pallla,

our brain is prone to pinking and heat sizing too!
So if it is running smooth don’t worry and enjoy it! My friend owner of a Piaggio center have done 20000km with is polini 177 and no problem. With my one, wich has the barrel porting altered, longstroke and reed, up to now has done 6000km no prob (3000 of which travelling ). Just avoid in hot summer the HP4 flywheel, don’t push in the overev for too long and yours will last long too.
Polini and DR kit tend to size if not correctly jetted and timed. And as far as the break up period with this kit it works well short, few seconds of high rev in lower gears and then cool down. (Of course my opinion)
When it will come a warmer wheater and you will be using your scooter again check plug and exhaust end to see how your engine is doing.
Or do as Adrian told you: honing. I just find it too expensive, and then what the hell, if it happens what we are afraid we can always buy another kit!
Polini and DR they have too live too and their kit don’t cost a fortune and are excellent!
I can only say that for most professional tuners Polini 177 is the best all round kit for PX 125 - 150. There must be a reason.
[H]

hello Pallla,

I just was thinking about your concern.
I have just posted few picture in my :
http://vesparacingteam.blogspot.com (have a look if you want)
There you have a scooter I have done with polini 177 kit, longstroke, reed, cylinder and piston altered etc.
It doesn’t pink, it din’t size, it is not that well treated, it reaches 125kmh fast (top speed a little more) with 21/65 ratio that it is not that long, up to the 3 if you open the gas fast you can feel the front wheel becoming light and the owner brought it back to me just to modify the exhaust mounting.
It has already done 4000 kmh and he said that he was not that carefull breaking it in, he followed my advice of short high rev burst on lower gears and then cooling down. But I did a dyno carb set up etc…
So problems with this kit must come from :
either the use of too small carb
wrong set up of carb or time
or bad owner karma.

That is just to reassure you again.

[:roll:]

Hello !

Thanks for the input, so it is most up to the user
i understand, and no manufacture probs with the kit.
Thanx !!

[:)]

BASICALLY FROM WHAT I HAVE HEARD ABOUT THE POLINI KIT THE PISTON IS VERY TIGHT IN THE BORE OF THE BARREL, SOME PEOPLE I KNOW HONE THE BARREL TO GIVE IT BETTER TOLERANCE. PROBLEMS OCCUR BECAUSE PEOPLE DON’T RUN THEM IN CAREFULLY ENOUGH. JUST RUN IT IN VERY CAREFULLY, LIKE IT WAS BRAND NEW, FOR 1000 MILES (1500KM) CHECK YOUR JETTING AND TIMING IS CORRECT AND YOU SHOULD BE OK. I HAVE A NEW DR 177 KIT AND THE PISTON SEEMS VERY TIGHT IN THE BARREL AS WELL SO I AM THINKING OF HONING IT BEFORE I FIT IT, JUST TO GIVE IT A HAND AND ENSURE I DON’T HAVE ANY PROBLEMS.