Smallframe Crank

My engine is stamped as a 1975 V90 & I thought the Malossi 136 kit was a straight bolt on kit?

But I've just looked at my original crank and the wristpin in my new Malossi 136 kit. The diameter of the hole in the conrod is to small for the wrist pin???

Will either of these two cranks be ok & whats the difference between a 20/20 cone & a 24/25 cone?

20/20 racing Crankshaft
http://www.sip-scootershop.com/EN/Produc....Vespa+PK80.aspx

24/25 racing Crankshaft
http://www.sip-scootershop.com/EN/Products/45091000/Racing+crankshaft+Vespa.aspx

Also should the ports be chamfered on the cylinder before I install it?

Thanks.