tjurek51
CB750 New member
Bike: 1980 CB750F Supersport.
I'm installing a new camshaft which is much higher lobed than the stock camshafts (Webcam Grind #110, part 55-491). I'm new to this precision measurement stuff, but here's what i have;
Valve lift: .395" (10.03mm) on both Exhaust and Intake.
Starting at 20 degrees BTDC @ 0" lash, using a dial indicator i measure .388" of travel on the exhaust side and at 20 degree ATDC @ 0" lash i measure.326" of travel on the intake side.
Starting at 0 degrees TDC @ 0" lash, i measure .312" of travel on the exhaust side and .245" of travel on the intake side.
here's where i'm stuck. in my head i'm thinking if the valve lift is .395", at all measurements it looks like i could hit the piston. Thus, i know i'm missing something.
Is there some calculation that is used to determine the correct P-V clearance? everything online just tells me the measurement is my clearance and don't actually tell me the calculation (if there is one). if i use the measurements i got, they look very large compared to the recommend .080" on the Exhaust side and .050" on the intake side.
any help is appreciated.
I'm installing a new camshaft which is much higher lobed than the stock camshafts (Webcam Grind #110, part 55-491). I'm new to this precision measurement stuff, but here's what i have;
Valve lift: .395" (10.03mm) on both Exhaust and Intake.
Starting at 20 degrees BTDC @ 0" lash, using a dial indicator i measure .388" of travel on the exhaust side and at 20 degree ATDC @ 0" lash i measure.326" of travel on the intake side.
Starting at 0 degrees TDC @ 0" lash, i measure .312" of travel on the exhaust side and .245" of travel on the intake side.
here's where i'm stuck. in my head i'm thinking if the valve lift is .395", at all measurements it looks like i could hit the piston. Thus, i know i'm missing something.
Is there some calculation that is used to determine the correct P-V clearance? everything online just tells me the measurement is my clearance and don't actually tell me the calculation (if there is one). if i use the measurements i got, they look very large compared to the recommend .080" on the Exhaust side and .050" on the intake side.
any help is appreciated.