This is another test to see how much power
could be made without the use of expensive exhaust systems and throttle
bodies. This bike received some Pistol high compression pistons and a
37/31 valve conversion developed using the flow bench, velocity and
previous dyno data. The ports were not carelessly hacked to
a large size. They have been reshaped to direct the flow where we
want it with a good airspeed to match the engines camshafts and
intended RPM range.
After the heads were finished with new
colsibro valve guides and the new valves, they were fitted and the cams
were degree'd 5 degrees advanced only. Click
on images to enlarge
The result was huge seeing as this bike
still had stock air box and filters, stock 50mm throttle bodies and a
stock 996sps exhaust system with open cans.
The lower dyno graphs are of a 996sps with
air filters and open pipes before and after mapping. The top line is the
same but with Pistol pistons and a proper cylinder head re-work.
Why waste money on big expensive exhaust
systems and throttle bodies when the truth is 150hp can be had with near
stock components. All the power is in the head!