Originally Posted by mrgsr
I just used a carbide grinding tool and cut the scoop out that
im pretty sure this was all due to the tune still
what is cc ? do you mean by creating the scoop i have created more or less compression ?
For aluminium, sometimes is better (and cheaper too) to use an HSS bit (there are plenty of sizes, forms, etc...). Carbide for the aluminium is way overkill. Is good for cutting the steel on the crankshaft and similars.
Creating the scoop, in fact you enlarged the cavity of the Combustion Chamber, so the compression (Cranking pressure) on the engine is lowered, to regain the compresion a check of the Combustion chamber is needed to be done (check the clearance between the piston and the combustion chamber before removing any shim).