1st Dyno is the Hornet.
Green line: Only reprogram ecu 92,34 hp (Unmodified oem was 90,6hp)
Blue line: (95,90 hp) intake cam cbr600rr with advance angle setting (3,05mm at TDC), CB1000R intake funnells, modified headers to 2ndary collectors from cbr600rr, decat, 50mm exhaust pipe (from 42mm), (i kept the oem resonator) and oem rear muffler.
Red line: (96,70hp) All the above plus a aftermarket rear muffler
Stock cbr600rr 2008 model european spec v my hornet 600 with the above mods.
ps. The dyno guy said the cbr600rr was measured with an older version dynojet and was a bit more optimistic. He told me with the new dynojet the performance would be near 107-108hp.
Even with that parameter still my bike have12hp less !!!
Sorry for the late response.
I have the hornet as a project and trying to make it fast as a stock cbr600rr.
As for cbr600rr pc40 i think doesnt not need a porting modification if the setup is mild. the head is enough good and big.
i would suggest (even with the stock camshafts setup) only the hrc guideline steps.
Port matching, smoothing the head near to the valve seats, 0,15mm skimmed head for 12,6:1 CR, and reprogram the fueling (maybe also the ignition timing) with testing on the dyno.
Thats mods are easy an safe to not hurt performance. A full port head job would be suggested for more wild setups (bigger pistons, bigger camshafts) as for example.
This is lots of work to get factory 600RR specs. Might as well do little more. For better gains, I recommend:
- variable-radius valve-seats. Makes bigger difference than anything else
- reshape ports for higher velocity. When upgrading my '05, flow-bench testing showed ports weren't flowing as fast as possible for maximum cylinder filling. Solution was to weld up ports and re-shape. Came out like this for much better flow across all lift amounts and flow-rates used by engine. Note parabolic shape rather than linear cone.
Similar to what's done with R1M
- cams will need adjustable gears and dyno-tuning. Hornet will probably need wider lobe-centres. Start with 1-2 degrees more than stock with 2-3 degrees later intake-closing
Thanks for your photos and advices.
The hornet cylinder head is very similar to the CB 1000 r head. It has 36 mm throttle body size so a lot smaller than CBR 600 RR. Also the cylinder port of the hornet head shape is more parabolic than CBR heads. The real problem of course is that the chamber and the valves are the same as CBR but the inlet ports are a lot more narrower. This restricts the power in the high end range. The CBR 600 RR PC40 inlet ports are smaller and better shape than previous generations of CBR, but in comparison with the hornet inlet ports are still huge.
I am re-shaping the hornet inlet ports to a dimension between the OEM hornet ports and CBR 600 RR pc 40.
As for the camshafts the CBR uses a inlet cam off 245° at 1 mm with 8.3 millimeter of valve lift and and exhaust camshaft of 225° at 1 mm with 7.2 mm of Max valve lift.
The hornet uses a inlet cam off 230° at 1 mm with 8.2 Max valve lift and the same dimension exhaust camshaft with CBR.
My final setup of camshafts are the inlet camshaft of CBR and a re-shaped inlet camshaft of hornet to the exhaust side.
So basically my final setup will be with bigger camshafts in comparison of a CBR.
My logic for valve timing of the camshafts is to advanced them because I will never run the engine in the RPM range of a CBR.
OEM real rev limiter of the hornet is 13.500rpm.
CBR pc40 rev limiter is 15.500rpm.
My goal is to have a rev limiter of 14.500 up to 14.750rpm.
After all even with some advanced cam timing into the hornet set up with a use of an inlet CBR camshaft still the valves will close later than a setup with OEM 230° of camshaft.
Also my theory the inlet hornet camshaft to the exhaust side, with 5° more duration and 0.9 mm more valve lift from the OEM exhaust camshafts will flow better at higher RPM range.
I think the CBR OEM exhaust camsfaft is not very big and with not so aggressive timing for better emissions.
Hear some photos of my cylinder head that I prepare
I've never been involved in flow testing of heads but the equipment used is talking my language. I was wondering how you measured/calculated the airflow. But now I know. Selectable orifices and oil manometers. Old school tech. 👍
Full disclosure, I've been doing commercial test and balance and building commissioning for over 20 years. So anything to do with air or water balancing peeks my interest.
Some proggress. All cylinder head ports are ready, I need finishing also the chambers and I am waiting also the new throttle bodies insulators for port matching. Next step skimming the surface clean and assembly. I am also waiting for a new head gasket. I hope to have it ready at middle of April..
Just skimmed the head 0,3mm, and cleaned the head to washing machine (for cylinder heads). Saturday I will lap the valves to the valve seats, I ll start the assembly with the cbr600rr spring valve seats, double valve springs and retainers with new valve seals on inlet side, and for the exhaust side I will use the inlet parts from the hornet.