1982 Honda express nc50 Iowa version

Ok so I've been searching threads and it all comes down to no one really knows the restrictions for the nc50 Iowa.

I recently purchased one and really love it but the 25mph limitation is starting to kill me inside slowly. I have adjusted pretty much everything possible. Also I want to keep it as stock as possible. I did watch some videos about drilling out stock muffler on YouTube. I too out like 27-28 with doing this.

I did notice that the exhaust outlet port on mine is different from some of the others I've seen. Mine looks like the right one. Picture below. Should I port it out and would it help. Also if any info on the actual restrictions would be great.

IMG_9817.PNG

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

stock express only does 27-28 anyway so your Iowa isn't severely limited but that exhaust port may be the main limitation.

expressor.jpg

I just put an SHA clone carb on my express and gained 2 mph. Not much but 30 is better than 28.

I removed some material from my Iowa Urban's cylinder that looked just like the cylinder on the right. You can make it look like your cylinder on the left but you probably just want to raise the exhaust port 2mm at the cylinder wall. In other words, don't hog out the entire exhaust port where it meets the cylinder wall.

Of course, your stock exhaust is a real handicap as well. You may want to list what you've done to yours so far.(edited)

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

Main jet is also typically way too rich especially with that restricted cylinder.

Re: 1982 Honda express nc50 Iowa version

Honestly all I've done is a carb clean after the purchase of the ped.

Adjusted the needle positions on the throttle pin.

Switched to 92 octane. Lucas 2 stroke oil. Cut the muffler open and drilled holes into the internal pipes just like the few guys in some YouTube videos. Here the video

IMG_9757.JPG

Re: 1982 Honda express nc50 Iowa version

I do feel like I'm running rich. I go through a bit of fuel

Re: 1982 Honda express nc50 Iowa version

Master D. Baiter /

Cut a hole in the top side of the piston to match the boost port window, trim the side transfer skirts on the cylinder.

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

^I've got a feeling you will need to be more specific

Re: 1982 Honda express nc50 Iowa version

You have to be way more specific. Would you have any guides or pictures?

Re: 1982 Honda express nc50 Iowa version

You are correct lol

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

Well here's the windows he was talking about - see the two windows on intake side of piston. This is a different piston but used for illustration.

I assume you cut them to match the boost port when piston is at top dead center.

As far as trimming the side transfer skirts -

hondacylinder.jpg

I'll go with this. Correct me if I'm wrong.(edited)

Re: 1982 Honda express nc50 Iowa version

Ahhh ok I see thanks you for this. Might be a little more than what I want to do but I'm gonna possibly give it a try once it turns to winter here

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

I'll give it a go on an old piston.

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

He must have meant side transfer skirts on the piston and not cylinder.

Re: 1982 Honda express nc50 Iowa version

Ahh ok lmk how it goes.

Re: 1982 Honda express nc50 Iowa version

this page:

https://mopedarmy.com/wiki/PA50I_(PA50M)_and_PA50II_Information

and this page even more details:

https://mopedarmy.com/wiki/Honda_PA_Model_Differences_%26_General_Info

illustrate many of the ways Honda restricted their "slow" version of the hobbits, I imagine many of these restrictions cross over.

Namely carb, reeds, cylinder porting both timing - (like sleeves above covering transfer timing) and exhaust port sizes, also smaller pipe. and variator restrictions too.

Most all of the restrictions can be completely removed with some time and a dremel and maybe a few inexpensive replacement parts.

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

I don't think Honda had same concerns or legal incentives with restricting the nc50 noped as they did the pa50 MOPED so i doubt they went through the same trouble. I still bet only restrictions on nc50 were tiny exhaust port and subsequent over jetting. I bet a 70~ jet would improve things markedly.(edited)

Re: 1982 Honda express nc50 Iowa version

> Michael H Wrote:

> -------------------------------------------------------

> Ok so I've been searching threads..........

> I did notice that the exhaust outlet port on mine is different from some

> of the others I've seen. Mine looks like the right one. Picture below.

LMAO...that's a pic I put up here a couple of years back.

The cylinder on the right was what came on my express. The cylinder on left is one I bought off of eBay that already been over bored and came with oversize piston and rings seen in red boxes. The ped picked up a couple of mph with cylinder and over bore kit.(edited)

Re: 1982 Honda express nc50 Iowa version

> Jack Rutherford Wrote:

> -------------------------------------------------------

> Well here's the windows he was talking about - see the two windows on

> intake side of piston. This is a different piston but used for

> illustration.

>

> I assume you cut them to match the boost port when piston is at top dead

> center.

>

> As far as trimming the side transfer skirts -

>

> I'll go with this. Correct me if I'm wrong.

Also, Knife edge the the transfer port edges on the front of windows on the cylinder like the Polini to the left here.(edited)

20170410_010646.jpg

Re: 1982 Honda express nc50 Iowa version

I have both Iowa and non Iowa urban expesses, the intake manifolds are different, the main jets are different, and I think the port height is different, I haven't measured to be sure. Also the drag coefficient seems a bit higher on the Iowa.

Re: 1982 Honda express nc50 Iowa version

Jack Rutherford /

> live ɘvil Wrote:

> -------------------------------------------------------

> > Michael H Wrote:

>

> > -------------------------------------------------------

>

> > Ok so I've been searching threads..........

>

> > I did notice that the exhaust outlet port on mine is different from

> some

>

> > of the others I've seen. Mine looks like the right one. Picture below.

>

> LMAO...that's a pic I put up here a couple of years back.

>

> The cylinder on the right was what came on my express. The cylinder on

> left is one I bought off of eBay that already been over bored and came

> with oversize piston and rings seen in red boxes. The ped picked up a

> couple of mph with cylinder and over bore kit.

I bought one on eBay with the rounded exhaust port. It had not been over-bored. And I don't think the exhaust port had been touched.

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