Originally Posted by Cotten Mouth Chris
i was just thinking the the smaller circumstance of the tire might affect it im not to worried about waering them out like i siad their the next thing on my todo list
No, be it full OD new with skinnier centre section or worn out flatter centre with smaller OD, is not going to have any effect at all on the mapping that gets done.
Whatever the tire loss effect is, is more driven by the tires air pressure.
Being a low HP bike, you can run the rear at 40 psi on the dyno and still maintain traction.
At least that way you know your tire losses are minimized.
Pickier still, is making sure your chain has been well cleaned and lubed.
A gummed up chain uses hp.
Check out 919.org (LDH's site, I'm pretty sure he another one, or is tied to another one, but I can't remember the name)
Look for the Dyno basics info.
Ignorance is not bliss, especially if some one gives you curves based on MPH instead of RPM.
Only accept RPM based curves.
You should get both Torque and HP curves, before and after type, all on the same page.
Make sure the peak torque and peak RPMs are noted, do not accept trying to read the curve lines down to the RPM axis.
Being PAIR equipped engines, the 919 is susceptible to spooked A/F readings from improperly blocked off PAIR air, be sure to ask about how they are going to block it off.
919s are large volume X small radiator area type cooling systems, and once the engine is up to temperature, it's very easy to have the coolant temp get out of hand if repeated runs are done with no inter-run cool down.
The needle should not get past half way, and if the fan goes on during a run, that run should be torched, otherwise you will have improper fueling when the coolant is at normal temperatures (the Honda ECU starts enrichening past a certain coolant temp and the PC does not change this).
Don't ask for a full power mapping, they are too rich for normal street use, engine responsiveness will likely suffer also, as full power fueling tends to feel "flat" at smaller throttle X lower RPM combos. If you want a track day map, there are plenty of those kicking around to try for free.