Re: Simson 50cc high end porting

Kilian Münscher /

I have changed my mind again.

I am going with rotary intake.

I have started to make the first plate on which the rotary valve will sit.

And I have been gifted a 21mm carb by a friend. Not sure if I am gonna start with this on because on the intake ther should fit a 26mm or 28mm pwk carb.

I have made some images of the work so far.the duration of the rotary disc isn't the final one and I've made a custom rotor for the ignition that is smaller.

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Re: Simson 50cc high end porting

Kilian Münscher /

So I have finished the intake of the engine.

Even though I was going to weld on the intake to the engine I used jb weld stick high heat as I didn’t want to heat the engine up so much that the Aluminium would warp.

If the stick doesn’t work right I am going o weld it but it is worth a try.

I have also ordered a 28mm pwk carb.

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Re: Simson 50cc high end porting

Kilian Münscher /

Little update.

I am going to use to old kreidler 50cc scavenging system. That was employed on their rotary valve 50cc racers it produced between 14.5 and 15.5 hp.

There was also a piston ported version.

That produced a whopping 12 hp.

Re: Simson 50cc high end porting

Kilian Münscher /

Started with the resonance exaust.

I also am almost finished with the rotary intake.

And the cylinder arrived now i need to get a new liner for it. Does anyone has a idea where to get one.

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Re: Simson 50cc high end porting

Maybe LA Sleeve ?

https://www.lasleeve.com

Re: Simson 50cc high end porting

Maybe get in contact with Sander Mulder on here. He knows his stuff and also where to get stuff to do custom stuff. That's a lot of stuffs, but you get the drift.

Re: Simson 50cc high end porting

Sander Mulder /

On one of my builds i used a kawasaki cylinder sleeve from la sleeve

The other one, i bought a sleeve with no ports, made for simson;

https://kultmopeds.de/Simson-Laufbuchse-fuer-Zylinder-50ccm-ohne-Kolben-S51-KR51-Schwalbe-SR50-S53-Duo-4-Almot

Re: Simson 50cc high end porting

Kilian Münscher /

I have contacted someone that makes sleeves in Germany.

I have seen the simson sleeves that are being sold. The problem with the is that they are made for the "newer" kind of engine, that hase a other stroke and bore so the sleeve doesn't fit into my cylinder. And as far as i am concerned there are no new sleeves produced for that cylinder I have.

I am also almost finished with the exaust.

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Re: Simson 50cc high end porting

Such a cool thread. That rotary intake is way cool.

Re: Simson 50cc high end porting

Kilian Münscher /

Thanks.

Today I pressed out the line of the cylinder and started to cut the new ports in the cylinder.

I needed to weld on material to the cylinder.

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Re: Simson 50cc high end porting

Kilian Münscher /

Finished the 2 ports.

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Re: Simson 50cc high end porting

Kilian Münscher /

The company I contacted came back to me they wanted to have 250€ for the sleeve only.

I thought that that would be much cheaper more like 100€.

So thats a bit frustrating as I am not gonna spend that much money on a sleeve. Now I thought about maybe buying a completely new cylinder proberbly a doppler which are aprilia clones that produce hell of a lot of power as they are cheaper than the sleeve and maybe even going watercooled.

When I would buy a sleeve frome la sleeves how much would that be. I would need a custom sleeve as the they don't have any fitting ones for my engine.

Are they also so expensive or are the cheaper.

I am not going to spend more than 150€ for a engine.

Re: Simson 50cc high end porting

Dirty30 Dillon /

Why don't you reach out to them and ask?

Re: Simson 50cc high end porting

Kilian Münscher /

I have contacted la sleeves but they didn't respond now for nearly 2 days.

I am now thinking about casting and machining a zylinder myself with a thiner sleeve that is easier to get.

I was going to use the aprilia rsa port designe. There a a hole lot of people making great power with that port design like alex degenes with his old rotary valve spx producing 23hp at the crank and even his new engine with his home cast zylinder is using the rsa port designe.

The problem is that the stud pattern is way to tight on the engime to fit a rsa port designe (45mm square) i could widen it to 50 mm like the miniarelli am6 for which there a great zylinder like the bidalot rf50 wr. But I have done some work in fusion 360 and tge traditional rsa port design doesn't fit in the 50 by 50mm.

So the bidalot rf50 wr for the am6 must have a somewhat changed port layout. But i haven't found specific port angel and position numbers if anyone knows them please tell me.

Re: Simson 50cc high end porting

Kilian Münscher /

Sorry.

Of corse he is called alex degnes

Re: Simson 50cc high end porting

Kilian Münscher /

I started a new thread were i am going through the casting of the cylinder.

https://www.mopedarmy.com/forums/read.php?7,4411825

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