P50 motor tuning (English)

    Hallo


    At first, I am sorry for writing in English, but I am hopeless in German. Some of you might recognise my text because I have been asking the following in the other German Tradi forums as well.


    I have an extra P50 motor, which I am planing to use in a late 50s style classic TT racebike frame. I have been looking for knowledge to tune the engine for road racing. However, the knowledge for this engine is naturally all or mostly in German language. I am lookin for tuning tips to original engine. I want to keep it 500cc ad use original parts. This means I am not looking for modern aftermarket parts. P50 was used in rally right when it was introduced and my engine is actually possibly from the rally car, because it has filed pistons in it. Basically I am not looking for extreme power and limits for the engine, just some extra power for fun.


    I have found a couple of German pdf files, that have some information about making third by-pass port and cylinder port diameters. I need to start translating those. While doing this I have a couple of detail questions already.


    How do you think the engine would work without external flywheel in a motorcycle frame? This is what my plans are now. Light frame does not need that much momentum than a car body.


    As I need to buy a set of bearings for the engine, what kind of main and conrod bearings would you recommend?


    Engine obviously needs a new carburetor. Any good (preferably period, 1950s to 1970s) carburetor options in mind?


    I could use two-stroke tuning handbooks also, but for that I need to know what is the best rev. range for Trabant engine from your experience? How high it is save to go and how wide is the torque range?


    All good tips for power and reliability in tuning this wonderful disc valve unit are more than welcome. I would rather not "learn from mistakes" with this a bit rare engine.


    Regards Risto Nurmi (Oulu, Finland)

    Why what?


    Yes, that is my text in the other forum. As I said, I have asked the same from other forums that I have foun from internet. By this I am trying to reach wider group of people. I am not expecting that all Trabant enthusiasts follow all available discussion forums.


    If the "why" is for why am I doing this. Well, I have an extra engine and empty frame. And then I got this weird idea... Just for fun basically.


    Risto

    Hi


    I have been trying to dismantle the engine now, but man the pistons are stuck. I need to built some sort of frame so I can use more force and heat. I'va also found the gearbox solution.


    I have been wondering the production year of the engine. Wonder, if you could help. The engine number is 51-068950* and the cast number is 4160 015 80. Can anybody read these?

    2/1961

    Wenn ich einen See seh, brauch ich kein Meer mehr. :winker:

    vielen Dank!


    So the frame and engine are from the same year.


    What size carburetors have you been succesfully using in tuning Trabants? I mean the throthle diameter. I could get a decently priced 32mm Mikuni snowmobile carburetor, but I wonder if that is too big. There is not much material for enlarging the intake canal in the Trabi block.

    The size of the carburetor depends on the desired Leistung.Bis 45 ps should be enough a 30mm carburetor.


    thats my English with Google :grinser:

    Biete Serienmotoren, Sportmotoren, Rennmotoren, Sport-VSD, Vergaserumbauten, Regenerierung Drehschieberflächen, Gehäusereparaturen, Aluschweißen, Sandstrahlen mit verschied.Material auf Anfrage

    That is good to know. This makes 32mm carburetor way too big, because I am not necessarily looking for even that 45ps. I have to ask my friend whether he has some smaller leftover carbs.


    p.s. google English works fine. I'll translate the rest with the German-Finnish dictionary. :thumbup:

    If you want to stay with 30mm diameter, then you can use a satellite carburetor bohren.Du can also mount the 32mm carb to a 30mm intake, does auch.Der flange is thick enough to create a transition there.
    Translated the 36 Ps instructions by editing the engine can still danach.Du indeed a larger carburetor montieren.Ich think that your ideas should genügen.Kurbelwellen You can not make yourself, which you must kaufen.Ein lightened flywheel would still remain mounted.



    Was man nicht alles macht um die Trabantfreunde zu helfen. :thumbup:

    Biete Serienmotoren, Sportmotoren, Rennmotoren, Sport-VSD, Vergaserumbauten, Regenerierung Drehschieberflächen, Gehäusereparaturen, Aluschweißen, Sandstrahlen mit verschied.Material auf Anfrage

    Einmal editiert, zuletzt von Fg601 ()

    Thanks for info


    Did I understood correctly, do you have a 36ps instructions? I would like to read that.


    I am not giving away that 32mm yet then. The Krbelwellen i.e. crankshaft is going to the cranksaft specialist in our motorcycle club. Is there any particular reason, why the original crankshaft can not be used? Bearings are replaced of course, but are there any particular weak places in it? And As I said I have a good crankshaft from P601 engine. Do you know if it fits into P50 cases (it seems to fit)? The flywheel is another big question. Do you really think that the engine does not work without external flywheel in a motorcycle frame? This example has flywheel removed.


    http://www.flickr.com/photos/d…463913043/in/photostream/


    Maybe I could machine a smaller diameter wheel to replace the fan pulley in the front. The original flywheel can not be used in a motorcycle frame, because it does not simply fit.


    I'll ad the first mock up shots right when I get the engine dismantled.


    Risto

    36PS manual you will find in Web.Du can a crankshaft from 601 verwenden.Das housing must adapt werden.Das flywheel but you need to seal and for the Anlasser.Der engine will not let the cable run.


    to Link,thats a very spezial Project

    Biete Serienmotoren, Sportmotoren, Rennmotoren, Sport-VSD, Vergaserumbauten, Regenerierung Drehschieberflächen, Gehäusereparaturen, Aluschweißen, Sandstrahlen mit verschied.Material auf Anfrage

    Einmal editiert, zuletzt von Fg601 ()

    Yep, I just realised that I have already downloaded that 35ps guide. The lack of idle has been a bit of a worry in this project. I have to work something to solve that.

    Pumping up the old post.


    I was a bit amazed to read the dating of this old thread. Is it really 5 years ago! Well, I have now got some progress with this and some plans have changed. First of all, the bike is not going to track, it is going to street. So It will be a cafe racer. Secondly, I have a 600cc parts as well, I will however, make it first a 500cc, since I have all the parts (well, piston rings for 66mm standard piston still missing), but i will also prepare the tuned 600cc set as well.


    I will be using Pannonia P20 5-speed gearbox and thus I have a primary drive setting to solve. P20 has a gear driven primary drive. making gear driven primary drive would reguire a lot of machining and would be expensive. Setting a chain driven drive, again, would be a lot easier and cheaper, but would give me 5-speeds backwards! The solution would be to change the running direction of the engine. This is not a problem in two stroke engine, but has anybody done this to Trabant motor? The discs need to be reset, but does this have serious effect on intake flow, now that the window would be opening from the other edge than in the original setting?


    About the flywheel. I have been in contact with old racers from netherlands, who used Tarbant engine in a Metisse frame. The bike was very competitive. In the first version they did not have any external flywheel, and the engine worked fine over 2000 rpm. In a later version they made a small additional flywheel to balance the engine. I will be using either Bosch or Suzuki flywheel magneto, which gives me a bit more rotating weight on the crank.


    There is some pictures here.

    Hi


    project continuing slowly but steady. Do you have any tips how to find piston rings for P50 motor? Originals are probably hard to find, but do you know any modern replacements that would fit either straight on or with little bit of filing?


    I got the transmission. Now I need to marry the Trabant cases with P20 transmission.


    [Blockierte Grafik: https://lh3.googleusercontent.com/Wfl50SfTk9bYFOwxr6Xtja5w1-G7_kBsh7jvZOblcL5E9QlYwoWm08kApQTeDq6_sm6LHNKxcYz6mCOtpCPX6AQnfuTlXGS_iis75mkOfEm-MkODok7f0VY6FzScFTDSgPNz2BzWjQUhAyXSDdy2zYZTQx3fBPZ8fbgk-XniO92rSQWdeMYHYNN7jwmH_0eONf_HEdf81zUjn0h2DtOI4KsuCccg6ojaZiek37DjoYTHenb8GY9En6iaeheZiX_Asl1w7KsEkMQt_OrXCVCU8z0onEaLQqjzP_2VqelOaicutX92LbQpVbxSMN2xSvRxeUck4R48dxkSgyJj3V59Wu58Smzze1eWOTff1V4aHVB3gdLUvquWl3BHaT1wSRvfhZYzmwy1C51DEhzZYApmHB-p_M0AfL86NPVIx6F8p-arCL33X6UTMn4Q-ycH4m_O4UkeDNherg2j9AMz5WETNOngy27eYAVSQqaHaUqyHdFNZQhzoRohQV_EjNaJUVEintckuanl37TNYzTGokN9gQTey1NBTwZpmTR_u6l2USbwqvbQVvJrhfEaYtwb7C74mzscqeUcsjPEliAJH-YxEUYM0oyBGRLbSlCxkmAkpUaubyYpw3EM=w293-h220-no]