What does the tech suspect kiwi? Does it have a cooling issue,why is the rad off? Does the motor run smooth? Just a loss of HP...
Same dyno? Same tech?
Rubb.
Radiator is off because the only way to remove the valve cover is thru the front, radiator has gotta be out of the way.
All checks have been performed, all compressions were 135 psi cold.
valve clearances checked (2 of the inlets were just below the min so they were shimmed to correct clearance) and comps rechecked again at normal operating temp, 165psi. Mr Suzuki says the serviceable range is 174psi min to 210psi max.
No trouble codes appearing or logged in memory.
The throttle bodies removed to give full air availability to the cylinders.
The throttle plates primary and secondary were checked for correct operation from idle speed to 13,000rpm. All opening fully so no restriction to air.
The variable valve timing actuation is also working normally, through the full range.
The cam/valve timing checked and all marks correctly lining up at TDC.
Now, on the dyno graph the air fuel ratio graph is around 14 to 15 until it gets to 4000rpm . . . then drops to 11.5 right thru to red line, very rich.
The motor runs smoothly, just lacks power.
We are suspecting the exhaust system's catalyst may be blocked or restricted, the exhaust system is stock all the way to the muffler which is a slip on Yoshi.
This is especially possible if the owner has used leaded high octane aircraft (helicopter) fuel which is available at racetracks here in NZ.
We shall see . . .
It's only a theory we have at this stage, but we intend to test that theory by fitting a full Yoshi system and eliminate the catalyst altogether