MOPED ARMY

If you don't Radius your Polini, you will not have as much power, and you will also seize your engine sooner. There are transfer ports in the jug that are not in the case, so if you don't create them, you will get a hot spot on your piston. Enjoy it while it lasts!

"radiusing" is port-mapping (matching)

I'll need to do this soon as well. If anyone can post before and after pics of their engine case halves, that would be awesomely helpful to us first time polini folks.

Thanks for the explanation RJ!

I do have more questions, if you don't mind. (I always enjoy learning more about these babies).

1) You mentioned that the Polini jug has ports that are not on the Puch case. so does that mean you have to cut entire new ports in the Puch case for effective use of the Polini?

2) I've also heard of case matching, which is where a kit jug's ports don't align exactly with the ports in the case, no? In this case you dremel to get them lined up - correct?

3) There was another thread on Moby's (and likely the same on other models) where there was discussion about lowering the bottom of the intake port and raising the upper edge of the exhaust port in order to get mor transfer. the mentioned radiusing the edge of your enlargements so you don't catch the rings. If you do this procedure (making the opening in the cylinder wall bigger) how far back into the port do you need to remove metal?

4) I also read comments about working on the ramps. In the second picture in the first post in this thread http://www.mopedarmy.com/forums/discuss/7/50431/50431/ there is a picture of the bottom of the cylinder, and in the transfer ports is a divider (like the webbing between your fingers). Are they talking about dremelling away material here, in order to make the transfer ports larger?

Lots of questions, and I have this Malossi kit to pu ton one Motobecane, and I'm thinking about porting the jug I take off to put on my other Moby, and compare the results.

I can competently answer two of your questions.

1) Yes, there are ports on the Polini for Puch that are not in the case normally. There are two of them, and if you look at the gasket laid out on the case, you can see where they need to be. Color this area in with a permanent marker so you can see what needs to be removed. I use a dremel to outline them, and then I have a hand file that is the exact right size and I use that to take the material down to where I want it. The picture in the other thread shows these transfers, they are on the top in the picture.

2) Case matching is for both stock and kits. I've never done it to a stock engine, but I hear it helps a little. On a kit, it makes a world of difference, when you look at how big the transfer ports are on your new cylinder and how small they are in the stock case, there is no reason not to. The case becomes a bottle neck, and those are not good.