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Classic 50cc racing bikes......homebuild!
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Fri Sep 21, 2012 9:13 pm    Post subject: Classic 50cc racing bikes......homebuild! Reply with quote

If there is any interest i like to post about my 50cc racing addiction.




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Roger-hatchy



Joined: 07 Dec 2007
Posts: 2144
Location: Tiptree, Essex

PostPosted: Fri Sep 21, 2012 10:17 pm    Post subject: Reply with quote

I love em.
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Rick
Site Admin


Joined: 27 Apr 2005
Posts: 19211
Location: Cheshire

PostPosted: Fri Sep 21, 2012 10:18 pm    Post subject: Reply with quote

Tell us more!

RJ
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Rick (OCC Admin)
Various 1920s-1960s - Austin, Morris, Commer, Dodge etc.
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Fri Sep 21, 2012 11:50 pm    Post subject: Reply with quote

The red and white bike is the bike i am racing at this moment,i built it last year using an Sachs engine from 1969.
I built the frame,rebuild the engine with a rotary disc inlet,home made cranck,home made close ratio gearbox,stronger clutch and tuned the cillinder..........almost 20 hp measured on the rear wheel.
These bikes are capable of more than 100 mph.
Here are some pic's of the build........




Some pics of the engine building the rotary valve inlet.....



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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Sat Sep 22, 2012 12:16 am    Post subject: Reply with quote

When the whole bike was mocked up and all parts fitted it was broke down and painted,then began the fun stuff.........








When it was ready the real testing began........

Next weekend we have the last race of the seison,the bike has done well,is fast and reliable,only some minor problems like a broken clutch handle,cracked exhaust and a head gasket what blew out.......nothing worse happened and that is pretty unusual for a new bike so i am happy about that.
Next time i'll show another project what is still going on,building a replica of the 1964 50cc works Suzuki,the bike kiwi Hugh Anderson world champion with.
Because there are no parts from such a bike for sale i had to make every part myself including the engine.........wait and see.......... Rolling Eyes
René
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Roger-hatchy



Joined: 07 Dec 2007
Posts: 2144
Location: Tiptree, Essex

PostPosted: Sat Sep 22, 2012 8:53 am    Post subject: Reply with quote

That is a work of art
Thanks for sharing.

Do you also do all your own castings as well.
Looking forward to more of your fine work.
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D4B



Joined: 28 Dec 2010
Posts: 2048
Location: Hampshire UK

PostPosted: Sat Sep 22, 2012 9:21 am    Post subject: Reply with quote

Simply STUNNING ~ fantastic Cool Cool Cool Cool
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Sat Sep 22, 2012 10:05 am    Post subject: Reply with quote

Roger-hatchy wrote:
That is a work of art
Thanks for sharing.

Do you also do all your own castings as well.
Looking forward to more of your fine work.


Some of the small castings i do,the bigger castings a friend who works at a casting firm will do for me as a favor(cheap)
For an example the casting of a small insert in the enginehalf to make a disc inlet is easy to make,just pore in some melted aluminium into the casing.............

Then remove the casting and put some industrial glue in the casing and screw the casting into the casing........

After the glue is hardend mill the casting flat.

A bigger casting like a complete set of crankcases are more difficult,these are the moulds and castings of my Suzuki rm64 replica engine.



It took almost 6 months to make the moulds from plywood Rolling Eyes
As you can see when the casting is done there is a lot of milling ahead,now it is only a big heavy chunk of aluminium.
René
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Sat Sep 22, 2012 10:19 pm    Post subject: Reply with quote

Some pic's from the millimg process of the Suzuki replica,remember that i only had some pictures from the outside of the engine so i made the outside look-alike and the inside i had to invent myself.....









The last pic shows the sprockets of the ignition drivetrain,the original bike had the same system to drive the magneto.
In fact a stupid system,unreliable,and costing almost 1.5 hp.......
In my replica i am using a battery ingnition,more reliable than a magneto but i use the same stupid drivetrain Embarassed
Next time more,if you have any questions just ask,try to ask in simpel english because i am Dutch and my english is not so very good.
René
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Bitumen Boy



Joined: 26 Jan 2012
Posts: 1183
Location: Above the snow line in old Monmouthshire

PostPosted: Sat Sep 22, 2012 10:32 pm    Post subject: Reply with quote

I'm impressed. Do you make the gears yourself, or salvage / buy them in?
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Sun Sep 23, 2012 7:34 am    Post subject: Reply with quote

I try to use gearsprockets that are already available in several brands of mopeds,easier and cheaper than making it yourself,but when a gear is not available i buy blanks and make those fit to the axle. Wink
The gearbox in the Suzuki is 90% Kawasaki ar50,the cranck own design Sachs,The clutch will be made from parts of:Simson,DKW and home cooked.The cillinder is a russian moped example,the cillinderhead is Zündapp.
René
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Rene



Joined: 06 Jul 2012
Posts: 120

PostPosted: Sun Sep 23, 2012 11:58 pm    Post subject: Reply with quote

When the milling on the crankcases was done it was time to put things together and testfitted the block into the frame






The frame was already built before the engine was done,i had a testdrive with another engine fitted(Sachs)to check out the drivabilaty of the frame.
It has a good roadholding and is very easy to race so that is not something to worry about.
Here some pic's of the Suzuki with Sachs engine leading the pack Laughing



Next time more.........René
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poulmba



Joined: 09 Nov 2012
Posts: 1

PostPosted: Fri Nov 09, 2012 10:43 am    Post subject: Reply with quote

Beautiful, stunning.. and for sure a work of art..

I'm building a 50cc Sachs racer myself at the moment and any inspiration and info is much appreciated..

My hat off to you sir, bloody nice work..

Please keep posting Smile
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