The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

I was going to try and get the most power out of a ported 50cc cylinder with a rotary valve and a 28mm pwk nock off carb. Which by the way has got a really high quality for the price of only 18€ including shipping.

The problem why i discontinued the project was that that the new liner fitting inside the old cylinder was way to expensive for me (250€) so now i am going to cast a cylinder in which a cheaper liner fits.

The cylinder is based around the rsa port designe. And is mostly a copy of alex degnes cylinder withe the big radii on the transfers and the ports that bend only in one plane. The post on which I explained how I costructed the rotary valve was called simson 50cc high end tuning.

15999093325379064813955583074215.jpg
15999093734742675968351804197826.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Martin Fotak /

Is that plastic?

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

> Martin Fotak Wrote:

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

> Is that plastic?

3D print mock up I'd imagine. Or super light race technology alien type material.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Yes thats 3d printeg pla.

I am going to lost pla cast it which means i am going to suround the plastic cylinder with plaster thaen burn the plastic ouz and cast mrtall in to the plaster.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Just spray it with Teflon

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Today the space plate for the cylinder arrived. Which will be welded onto the crank case mainly to get the extremly big space between the cylinderstuds.

Of course the plate need to be cut in half on on each half of the case. Now I am only waiting for the new liner to arrive hopefully tomorrow.

Next I am going ro carve the port in the liner and then cast the cylinder around the liner.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

A picture of the space with the cylinder.

1600177905169656874808936955401.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Can't cast the spacing into the bottom of the cylinder ?

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Could do that the problem bit the problem would still exist with the large almost 10cm by 10cm stud spacing on the cylinder

Also the space will not be screwed on but weldet on it is just that I don't need to wep on so much.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Dave Thacker /

I take by your title you are following 2 Stroke Stuffing.

I see no reason not to put some fins on the cly to pick up radiant area. Other than of course making the casting more difficult. Also, why not connect the head stud bosses to the cly sides and fare them in?

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

I am gonnaput fins 9n just that I am gonna weld doese on after casting.

I am still needing to think about the cylinder studs for a bit.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Sander Mulder /

why dont you use auxiliary exhaust ports?

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Sander Mulder /

Cool project, just some tips,

WhatsAppImage2020-09-16at14.21.50.jpeg

if you want a good cylinder, i would cool the exhaust duct more, you have the room for it.

w0DtP5J.png

something like this.

WhatsAppImage2020-09-16at14.21.51.jpeg

and, i wouldn't cast this thin, you can machine it later.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Dave Thacker /

I notice another item. The speed of the flowing coolant in the critical areas will be based on volume it's flowing through. Perhaps the huge area on provided will have it moving very slowly around the bore.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Sander Mulder /

i'll shoot some pics of my 86cc coolant flow at the top of the cylinder

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Sander Mulder /

a few holes in the head for the coolant to get through.

so... i would use your current design for the coolant, but adjust the head to it

WhatsApp Image 2020-09-16 at 16.34.00 (1).jpeg
WhatsApp Image 2020-09-16 at 16.34.00.jpeg
WhatsApp Image 2020-09-16 at 16.34.01.jpeg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

yes i am working on a better version of the cylinder with better cooling and poperbly with aux exaust ports. and i will try to let the water flow around the exaust first similar to to bidalot cylinder.

My original thought with the double ex port was that i would get a higher blow down area as I only have one bridge. (but bigger)

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

I am thinking about the cooling around the exaust to.

I designed it that way it is at the moment manly to make it easier to cast.

On the previous casting attemps of me a was able to get good result even to wall thicknesses as low as 2mm's.

I was thinking about welding on cooling fins to the exaust afterwards.

But I will probably do a re designe.

I am using to 2 exaust port designe for two reasons.

1. Cause its easier to cast and when done correctly I should get more blowdown. But i am not sure about that.

2. Auxiliary exaust ports should have a higher power output potential. Mainly to to faster blowdown flow in the Auxiliary ports thats why I kept the exaust port bottom pretty far up and keep the size of the exaust opening quite small (80% of port area)

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

The liner arrived today.

In the new design I will use a 100% of bor exaust port but with bridges not like 2strokestuffing.

To not have short-circuiting between the transfers and the ex port the cylinder will be turned around 90° and use a closed end piston pin.

I haven't found where to buy one so I was thinking about tig welding it shut but I think it would warp a bit to much.

16003519483065328939227932150599.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

With bridges it shouldn't have a ring issue. I think this is really swell man.

...That captive ring setup he's working in blows my mind. Especially the Piston itself. It's such a novel design but I don't see any reason one couldn't use that Piston design with standard rings...

Certainly would have helped me out when I was starting out. I have a Piston ring graveyard around here from 20 years ago when I diddnt know how to install them correctly.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Yes alex degnes does fucking great shit.

And he is so inspiring or at least for me he is.

I dont think that he could use a normal ring as the ring without the t shape at atleast the exaust the ring would snag instantly. And he needs to have that captured ring to dont need bridges for a better exaust flow and higher blow down specific time area.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Working on the new cylinder designe.

Atm

Almost 100% of bore!!

16004354015511484079995013932290.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

I just hope that you and Sander dont grow out of 2t building. Just keep inventing it like Alex has over his life. I watched some videos on his bikes and it looks amazing, too bad I dont understand the language they were speaking. Ha!

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Hope so to thanks.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Roughly finished the weld on spacer.

Next I am going to weld it on the cases.

I will also start with the liner soon.

16005132279199211031596011670675.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

I started to weld the cases.

Now I just realized that I have a problem. Because the cylinder is 90° turned the skirt of the liner is now in the way of the rotary inlet.

20200919_142847.jpg
20200919_150917.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

Almost finished with the new cylinder.

16005937361811002393791144796738.jpg

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Sander Mulder /

Yess it’s looking better!!

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

This time water comes up from below the exaust port and then goes around it. Pretty much like the bidalot.

Re: The 2nd most powerful 50cc engine. (Casting a cylinder)

Kilian Münscher /

That cylinder looks like it made for scooter engines.

Did you fit it to a puch or was it run on a scooter engine.

I am just curios.

Of it was run on a puch du you have any

I meen the mallossi (edited)

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account