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Hello,
I want to do the right port matching on the original piaggio crankases that will fit the ports and boost on DR EVO 43 cylinder. I’m still not sure about using the liquid metal-epoxy for proper form (filling) of ports on the original crankases that fits excatly to DR EVO cylinder.
Is filling the ports with epoxy on the original crankases required (necessary)if I want to get the max efficiency from DR EVO cylinder?
What about the sufficient sealing between the cylinder and crankases in case that I do not do the job with liquid metal and just widened the ports that will fit the DR cylinder. I will use the original alu base gasket from polini 43 which is almost the same shape than DR EVO just adapted for two additional booster ports.
I’m opened for your’s advice
Greetings
Hey,
You don’t need epoxy for your engine.
You can grind the booster ports into your engine without the use of epoxy.
If you grind to far and cause a hole in your engine you’re able to use epoxy to close it (or mouldable aluminium)
If the porst in your crankcases are a bit to big you can widen them on your cilinder.
But normaly you don’t need any of those.
And the polini gasket may work if its 100%flat aluminium gasket are bitchy about “editing” them.Friendly regards
Hello,
I’m questioning this because the ports on original crankases are different shape (triangular) then the D shape ports on DR EVO. The DR cylinder has a different base – bottom sealing area then original piaggio cylinder.
If I leave this original triangular ports on crankases and just widen them to DR EVO I’m afraid that the sealing between DR EVO and crank wouldn’t be sufficient. Just thinking..:con
About the alu gasket, do you prefer that I make the one by myself with some gasket paper?
Thank you for your answers
Hey Ruby,
First of let me advice you to use paper gaskets instead of aluminium ones since the paper type forms better to prevent any leaking.
You could leave the original ports if you don’t have to maximize your output regarding the cilinder. However if you want to use the maximum power that it could bring it would be wise to adjust ports accordingly to the ports in the cylinder meaning you have to mill them into the carter. Best way to do this is to make a gasket from the ports of the cylinder and lay it onto the carter. This way you will have the best ports for your cylinder (since you copied the cylinder ports).
Yesterday Waarom? posted this picture:
Here you can see there is plenty of room to adjust your carter for porting to the cylinder ;)!
If you really want a tight fit then you have to adjust the carter and cilinder ports with the new home made bottum cilinder gasket to have the perfect tight and smooth tranfers.
As you see the black painted parts are from the DR cilinder, sow the main tranfers from the carter are a bit to large at some parts, those triangular remained parts have to be adjusted to the cilinder.
The use of liquid/paste metal inside a 2-stroke engine is a bad idea, because many time’s it came loose before the engine was running, not to mansion wath will happen with a running engine.
Succes 8)
TICKLING BARNThank you guys for your advices.
I will do the job like you tell me to do. No epoxy/liquid metal, home made base gasket and widened the existing original ports and two boost extra on the original crankases according DR EVO cylinder.
best regards
Any differences between the port size in the cylinder and the port size in the carter will led to air turbulence and less efficient flow.
When using the DR cylinder the cylinder port will be smaller at the middle of the large transfer ports so the air going up to the cylinder will hit “a wall” and cause turbulence.The best solution is to fill out the transfer port in the carter (alu welding or chemical metal) so that the port sizes match exactly.
/Dea
Hello Dea944t,
I agree with you about port matching between DR 43 cylinder and original piaggio crankases.
At the end I change my mind and made main and boost ports from DR43 to ori crankases and fill the differences with chemical metal – liquid alu.
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