Originally posted by Eric2004
The new novarossi long stroke engine having a stroke of 14.25mm and bore of 13.75mm seem to exceed the displacement of the standard (MR.NR. NSR) 13.8x14.0= 2.1cc
So the new long stroke engine creates more power is because it has bigger displacement?
The MT12 having same piston/sleeve set as the NS version but just with a longer conrod still has the same stroke (14mm)? Or does it have different stroke? Longer conrod seem to just effect the timing but didn't change the stroke value.
Help me please?
This engines you are refering to is still 2.11 cc.
The difference in strok that small, so it is not a reason to be more powerfull. Actualy longer strock-is more torq, but less top RPM ( it is in general).
Longer conrod is changing the angle of pressure to cranckpin, but it also required lift up sleeve and it brings crancase volume higher. So everything has t + or -. Conrod elenght has very little impact on timing. 1 mm longer conrod create less then 1 degree exaust and transfer timing ( please don't get mistaken that use of longer conrod in the same case isn't possible, so in aasumtion that longer conrod-longer case).
Just for insatnce 25 mm conrod, with exhaust height 4.5 mm and strok-154.41 degree. 26 mm conrod 4.5 mm exhaust height, 14 mm strock -is 153.74 degree.
In case what we call long strok engines-timing will have following # strock 14.25 mm, exhaust height 4.5 mm, conrdo lenght 25, so timing on exhaust come up to 153.31 degree. It will required to have little bit shorter pipe to have the same top RPM.
Conrod lenght, strock, timing are different things, even they affect each other.