04-01-2020, 09:56 PM
Hi Chris,
You still need the same amount of oil to flow in both systems given the same bearing clearances.
The two bearing pressure fed engine has further for the oil to travel to get to No 4 big end and if things are a bit worn then No 4 will be the first to suffer. (oil loss from the camshaft bearings has a huge effect on pressure and flow )
With modern cranks and shell bearings we are in a better place.
I would not use an original pressure fed crank with the way I drive the Type 65.
I run at 60 psi with my Allen Crank I only change gear when I run out of revs but have to use at least 2500 rpm as a minimum due to silly camshaft and can run up to 6500 rpm with a standard manual dizzy. ( at 30mph I have to be in third gear or it bogs )
I have changed the big end shells four times since 1995 with no regrinds.
You still need the same amount of oil to flow in both systems given the same bearing clearances.
The two bearing pressure fed engine has further for the oil to travel to get to No 4 big end and if things are a bit worn then No 4 will be the first to suffer. (oil loss from the camshaft bearings has a huge effect on pressure and flow )
With modern cranks and shell bearings we are in a better place.
I would not use an original pressure fed crank with the way I drive the Type 65.
I run at 60 psi with my Allen Crank I only change gear when I run out of revs but have to use at least 2500 rpm as a minimum due to silly camshaft and can run up to 6500 rpm with a standard manual dizzy. ( at 30mph I have to be in third gear or it bogs )
I have changed the big end shells four times since 1995 with no regrinds.