PA50 Porting

Alright, i have several pa50 cylinders, all from pa50IIs, and i was wonderring if anybody has done any porting on them. I was thinking to widen the exhaust a little, but it's already really close to the transfers in the cylinder. Is there a way i could shape the transfers at the case so that i wouldn't have any problems with short circuiting if i get the exhaust pretty wide?

Re: PA50 Porting

Raymond Rexroad /

I've opened up the exhaust port to about 0.67 of the bore, and raised the exhaust port 2 or 3 mm. The result, in my opinion, is that the power peak was shifted too high.

Try this:

https://www.mopedarmy.com/forums/discuss/read.php?f=7&i=63960&t=60564

Hope this helps.

Re: PA50 Porting

Yes! Do it. I've thought long and hard about this one but kits are just too damn easy to get.

Start with taking a chunk out of the cylinder skirt. Here's a picture showing how it's just sitting in the way of the gas flow to the cylinder.

If you can get a hold of a kit to look at you will see that the cylinder skirts are much smaller. But so is the skirt on the piston, so be careful, if you take too much off the piston might get wobbly.

Widening the exhaust port should be no problem. And the transfer ports too if you have the right tool. Honestly there's not too much in the case to take off and the hassle of splitting it makes it not really worth it.

Good luck.

Re: PA50 Porting

how the hell did i not find that other thread, i had the same title

Re: PA50 Porting

also, explain to me a little better what you meant about cutting the skirt, i'm not sure i understood. I'm trying this on a PA50 and a NC50(which might mean i just make one cylinder and try it on both)

Re: PA50 Porting

The cylinder sleeve is the part that slips into the case. Your piston is your arm, the sleeve is a sleeve, it goes in it. You can see it in the picture, it's the small arch above the crank. It extends further on either side, you just can't see it 'cause the case is in the way. So, when gas is trying to get to the cylinder it hits that obstruction and therefore does not flow as well. If you took a notch out of the skirt you would have a better flow.

But I've never done this and figured it out when I was high one night. So proceed with caution. I do however have extra cylinders, so if you run into problems, e-mail me and I'll send you one (for a nice price).

Re: PA50 Porting

eh, i'm not scared. but, i figured it out while i wasn't high, so i think, if something sounds good when your high, and when your not, it should be perfect, because it will be super innovative, and it'll be logical.

i just hope i haven't had too much coffee when i attempt it.

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