Re: Looking for some DOHC horsepower
Posted by shinyribs on Apr 24, 2012; 5:34am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Looking-for-some-DOHC-horsepower-tp3928486p3934433.html
Looking at the valve timing-the open and closing measurements-the 750 has earlier opening valves. That will produce an engine with more bottom end power compared to one with later valve timing. Basically,the 900 should be a little more highstrung than a 750,which should be a little bit more torquey.They oddly close at the same time???
BUT,the 900 has a longer stroke which will always produce more torque since the longer crank throw gives the piston/connecting rod a greater mechanical leverage over the crankshaft.Greater leverage,easier to push hence increased torque.
So the 900 has more stroke to help with torque down low,so it could afford the later opening valve timing without giving up bottom end.But that same valve timing helps with upper rpm breathing.
The reduced compression helps prevents detonation at higher rpms that the 900 should see,but will also give up some bottom end power.Again,it has a stroke to afford it.
The larger bore will bring the cylinder walls away from the valves providing the 900 with better breathing by unshrouding the valves.
Basically,bigger is always better.
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/Looking-for-some-DOHC-horsepower-tp3928486p3934433.html
Looking at the valve timing-the open and closing measurements-the 750 has earlier opening valves. That will produce an engine with more bottom end power compared to one with later valve timing. Basically,the 900 should be a little more highstrung than a 750,which should be a little bit more torquey.They oddly close at the same time???
BUT,the 900 has a longer stroke which will always produce more torque since the longer crank throw gives the piston/connecting rod a greater mechanical leverage over the crankshaft.Greater leverage,easier to push hence increased torque.
So the 900 has more stroke to help with torque down low,so it could afford the later opening valve timing without giving up bottom end.But that same valve timing helps with upper rpm breathing.
The reduced compression helps prevents detonation at higher rpms that the 900 should see,but will also give up some bottom end power.Again,it has a stroke to afford it.
The larger bore will bring the cylinder walls away from the valves providing the 900 with better breathing by unshrouding the valves.
Basically,bigger is always better.
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