The guy who said he Polini's are fucked if you scratch them is right.
However....it's power output for a 64cc kit is due to the reeds.
I had Andy at 1977 explain it to me. Basically the reed valve ensures that you are getting a clean air-gas mixture into the chamber everytime. The benefit? A 64 Polini acts and has the same power as a 80cc Metrakit. They're simply that good.
At leas this is what he told me. Having seen the Polini's burn by everyone in Sacramento last weekend....it's hard to argue.
Careful what you order from Treats. Don't get me wrong...he has good stuff - like, he cut me a GREAT deal on an Estoril pipe.
DON'T buy his 'no-name' bargain parts. They are shit. You will get exactly what you pay for: chinese rip offs. If you want Bing....buy Bing. Same for Dellorto. I've even seen some of the bargain jets he sell.....some of them won't even thread into the main tube. Others don't even have the driver slot cut into them.
So....I don't want to crap on Treats because he's a great resource, and I'd by from him anyday....just know what you're buying.
The Estoril, by the way RIPS. I have a 78 Magnum 1 speed. And it TEARS. I'm still running stock 12mm carb and intake and filter and run mid thirties. You won't have to do anything to your pedals. I would definitely put it on a kit port though because it's flat, not angled...which the stock E50 port is. Pain to cut and weld and rebolt.