What do you think about this port job?

    First of all, I`m sorry but I can`t speak German, so I`m writing in English. I want to ask you what do you think about this port job? http://imageshack.us/g/13/dsc0381dh.jpg/ I did it myself, all I paid for was the piston, everything else I had available at home, so it was a pretty cheap project. Just want your oppinion on the cylinder, if it`s a good port-job, or not.

    Re: What do you think about this port job?

    It looks like you took a lot effort. I like that.

    Question: Did you grind the exhaust bar? Because a problem is that there is no aluminium behind it. Therefore the heat can not channel into the cylinder. As a result the exhaust bar will bow into the piston and this will definetly lead to piston squeezing. So if you did not do this yet be shure you grind it. I would say about a tenth of a mm.

    "Das Denken ist zwar allen Menschen erlaubt, aber vielen bleibt es erspart." - Curt Goetz

    Re: What do you think about this port job?

    Well, I will do it for sure, it makes sense. Although, won`t there be more ring wear in that case? Also, I forgot the exact numbers, but I think the timing was like : 190 degrees exhaust, transfers - 132 degrees. Do you think it`s suitable for a 70cc cylinder?

    Re: What do you think about this port job?

    the transfer and exhaust duration does not depend on the capacity of the engine. 132 and 190 is okay, no matter if the engine has 50 or 500 ccm.

    Re: What do you think about this port job?

    I`m actually thinking of creating another cylinder, probably 60/4 or 50/4 with higher port durations like : Exhaust : 214 Degrees, Transfer : 138 Degrees, Intake : 200 Degrees. I want to get really high RPM - Something like 12000 and up. Do you think these port durations could get me up to these RPM?

    Re: What do you think about this port job?

    I didnt built any pure Race cylinders, but I think that youll have to stay around 200° with the exhaust.

    Achtung auf der A2 Berlin Richtung Dortmund zwischen Hannover Herrenhausen und Raststätte Garbsen
    ......ein perfektes Fahrzeug

    Re: What do you think about this port job?

    Zitat von Excill

    I`m actually thinking of creating another cylinder, probably 60/4 or 50/4 with higher port durations like : Exhaust : 214 Degrees, Transfer : 138 Degrees, Intake : 200 Degrees. I want to get really high RPM - Something like 12000 and up. Do you think these port durations could get me up to these RPM?

    Please dont do that!
    Dont take an exhaustport over 200° if you only will get more RPM.
    For this is the exhaust the most important thing.

    simsonalife
    ______

    Geht steil aufs Vorderrad!

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