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Old and New Head

Old and New Head Combustion Chambers

Close Up of the re-cut Combustion Chamber

Ceramic Coating to be done and some Cylinder/Piston work to finish and then test and run-in.


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do you have a drawing or specs on this modification,is it for the reed motor only?





        I believe this mod is good for both Piston Port and Reed Valve Cylinders, I don't have the dimensions as this was done by RKTek in the US and it is supposed to be Patented?. You can check their website out at http://www.2strokeheads.com/VintageMX.htm I hope this is of help Rob.


ok i have sent them a mail,thank you,what sort of jetting were you running on the piston port 490, my bike has gone off just cant get the jetting right,even with new bing carb,just cant put my finger on it,going to pull motor down next.


        I would start with the standard and play from there. I modified my Bing by using dry film on the bore and slide to help stop the wear and insure a closer tolerance. I also put a O ring seal under the needle to stop the vibration wearing the needle and main jet. I have also a couple of other modifications to do, but I have not tried yet. Please click on this link for information on jetting on the Maico 490.   http://storage.ning.com/topology/rest/1.0/file/get/1802225275?profi...


I am sorry the photo's are not that clear, but you get the idea




Kevin....RK Tec said don't coat the head. Email them and.ask. DG

Thanks Doug, I will email Kelsey and ask him what is best. I did ask him to send me Squish values and Deck heights for optimal performance with this head, but I did not get any response from him.




         Spoke to Kelsey and yes the answer is No Ceramic Coating of the head or piston top. I still have to do some port work and fit the larger de-comp valve before I get the head on the bike. Thanks for the heads up Doug.



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