PA50 Porting

Raymond Rexroad /

I've spent hours over the past two days trying to locate instructions on how to port PA50I and/or PA50II cylinders. I'm looking for specifics - like raise exhaust port 2mm, and the same for the transfer ports. In these hours of searches, the only result was information suggesting that raising the exhaust port on a PA50I 2mm can be done to match a stock PA50II port.

I'm hoping that somebody has experience that they are willing to share. Port maps would be good, too, but basic dimensions would be very helpful.

In order to remain a legal moped in Nebraska, it must be less than 50cc, so I'm looking to get maximum power out of the stock cylinder . . . .

And yes, I've looking for a performance exhaust, too.

Re: PA50 Porting

Raymond Rexroad /

Other information - if anybody has a PA50II cylinder laying around, could you measure the exhaust and transfor port locations (from cylinder top)? I do have a PA50I that I will "convert", and knowing this would help, too.

P.S. Yes, yes I know that I "should" just get a PA50II motor. Got one? I've got more time that $$ to spend, so I'll most likely just do some port work.

Re: PA50 Porting

There are some sites in Belgium and The Netherlands that are big into hopping up Hobbits (or Caminos as they are called over there.)

Get the Proma Circuit pipe. A PA50II with just this pipe modification will go about 38mph with no other mods. Not even any jetting changes.

Re: PA50 Porting

Does this pipe make the bike crazy loud? I would like one..I love the idea that it works with everything else stock, apeals to me a great deal....but if bike is horendously loud I will prob skip it, as is I get 30-33 mph stock with 200 lb me on it...on flats of course...

Re: PA50 Porting

Mine sounds like a dirt bike but not quite as load.

Tim

Re: PA50 Porting

cool, I just can't decide...thanks for input!

Re: PA50 Porting

i am also in your situation raymond, except that i already have a pa50II

here is a picture of the porting reccomended on one of the dutch sites, but this applies to a camino (pa50II)

...i will make a port map of a pa50II cylinder today if you want? as i have an engine apart already

1184744016_portmap.jpg

Re: PA50 Porting

Raymond Rexroad /

I've been looking for a Proma pipe - but no one has it in stock, AND there is NO estimate when parts will be back in stock. It is starting to sound like the Proma pipe may be a thing of the past.

Re: PA50 Porting

Raymond Rexroad /

Yes - a port map would be nice - then everybody could use it.

Otherwise, the picture you attached - just can read the numbers. Can you point me to the link (the source of the picture)?

Re: PA50 Porting

Stephen, the pipe does make the stock hobbit louder, but it becomes MUCH louder with a 70cc kit and a 21mm carb and intake. My hobbit is VERY loud at WOT compared to a stock ped.

Justin

Re: PA50 Porting

The only other thing I can say is I hear they are hard to find now.

Tim

Re: PA50 Porting

You will have to buy the Proma Circuit pipe from Europe.

Try these sites:

www.tuningschmiede.de

www.vdhparts.nl

There are probably more. I found these by doing a Google search.

Good Luck

Re: PA50 Porting

I see them from time to time on Ebay.be

Search for Honda Camino.

Viola.

Justin

Re: PA50 Porting

this is a port map i have just made

one thing, this cylinder has been lightly ported, the exhaust port has been enlarged slightly and the cylinder skirt cut outs have been enlarged slightly

hope it helps someone

ps. it is a big pic file, sorry dial-uppers

1184782825_port_map.jpg

Re: PA50 Porting

you can also get proma pipes here:

http://www.50cc.nl/frameset_eng.htm

Re: PA50 Porting

*measurements in mm

Re: PA50 Porting

Raymond Rexroad /

Thanks for uploading the port map!!!!

This should be of great benefit to at least some!!!!

Re: PA50 Porting

Raymond Rexroad /

I did a port map of my stock PA50I cylinder yesterday. I found that all ports, except for the exhaust are the same.

The PA50I port starts at 32mm from top of the cylinder. The port is 7.7mm tall, and is 18.5mm wide. It is very small!!!!

In this thread is a port map from a "lightly ported" PA50II. I don't know what lightly ported means . . . ? Anyway, to the point:

The PA50II port starts at 27mm from top of the cylinder. The port is 15 mm tall, and is 30mm wide.

This means that to convert a PA50I cylinder to PA50II specs:

Raise the port 5mm.

Lower the port 2.3mm.

Widen the port by 7.3mm, or 3.65mm.

I ported my PA50I yesterday as well. I had limited tools, but got my port opened up to 13.5mm tall by 26mm wide. I could not open it up any further with the tools that I had.

The difference is worth the work. My son has not determined the top speed, as it means exceeding the local speed limits (yes, he's a good kid!). But, he does report that he can now hold 25MPH (the neighborhood speed limit) using part throttle, and hold it up the hills, too.

The only down side is that the moped is now "cold blooded". It takes about a full minute to warm up and allow full throttle operation.

No plug chops yet, but I figure that I am close (running a 78 now).

Re: PA50 Porting

Raymond Rexroad /

I meant:

Widen the port by 7.3mm TOTAL, or 3.65mm PER SIDE.

Re: PA50 Porting

when i lightly ported my cylinder i raised the exhuast port and widened it ever so slighty, probably too much, the low end has suffered a lot...i would reccomend only going to about 28mm wide and 14mm high...even then the low end may suffer a bit

Re: PA50 Porting

What kind of increases could you expect from light porting while still running the stock pipe? And what about with an expansion?

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