compression

[talbotti]

i have gx200 clone with 14cc head that suppose to raise the compression to 10.5 with stock piston, i have a flat top piston in shelf so what would the compression rate then be?

 

[roccosbike]

https://www.dropbox.com/s/xjbj3h393u2wy3m/GX200 Compression.pdf

Here you go.There's more to it than people think, you also have to know your engines piston pop up Or deck height and they all vary from one motor to another.

 

[talbotti]

thanks very useful, next summer when i install the piston i have to measure the deck height.

 

[roccosbike]

thanks very useful, next summer when i install the piston i have to measure the deck height.

Once you know how many thousands your piston is in the hole @TDC you can look at the chart and figure out your CR. If you didnt buy a rod yet,check your in the hole depth first before you take it apart so you can buy a rod that gets the piston as flush to the top as you can first.

 

[talbotti]

i already have stock length rod from arc, alu flywheel, cam, 18lbs springs, 1.3 rockers, push rods, billet intake, mikuni vm22 and obviously the 14cc head.

 

[roccosbike]

i already have stock length rod from arc, alu flywheel, cam, 18lbs springs, 1.3 rockers, push rods, billet intake, mikuni vm22 and obviously the 14cc head.

OK, now you'll know what your CR is then.:thumbsup:

 

[talbotti]

OK, now you'll know what your CR is then.:thumbsup:

ööh what how i suppose to know thatut:

 

[roccosbike]

ööh what how i suppose to know thatut:

After you put your piston in your motor, check to see how many thousands it is in the hole @TDC then look at the chart.You already know what head your using.:drinkup:

 

[youngengines]

Check close for coil bind with those 1.3 rockers and 18lb springs.

 

[Newoldstock]

In the range of 11 to 11.5 to 1, depending on quench.

 

[rmm727]

Check close for coil bind with those 1.3 rockers and 18lb springs.

YES. Missed this. Surprised the engine will even turn completely over.

 

[talbotti]

YES. Missed this. Surprised the engine will even turn completely over.

i have tested it when the cam is at highest lift point the springs will have another 1-2mm room to compress