by Bill Jurgenson » Sat Mar 03, 2007 6:14 am
Coming to Chris' aid:
my first advice in tuning a Skorpion is to replace the wheels with those of the SZR. They are much lighter. Lighter wheels means less mass to accelerate and also less gyroscopic force to have to turn in so better performance all around without as much as touching the motor. The SZR wheels are the same size and so create no problems with vehicle inspection where that is a question. Suzuki RGV wheels also work.
Chris has Tz250R 3ma wheels 3.5/17 front and 5.00/17 rear
here are a few sample weights for comparison, in each case the complete wheel with tire, all spacers and brake disc;
fronts
SZR/TZR 4DL Brembo 3,00-17 = 9,2 kg
FZR Brembo 3,5-17 = 10,6 kg
PVM 3-spoke Alu 3,5-17 = 11,4 kg
Marvic 3-spoke Magnesium = 8,8 kg
Grimeca 3,00-17 = 11,5kg
rears
TZR 4DL Brembo 3,5-17 = 11,8 kg
SZR 4SU Brembo 4,00- 17 = 13,6 kg
TZR 3MA Brembo 4,5-17 = 12,2 kg
PVM 3-spoke Alu 4,5-17 = 15,8 kg
Grimeca 4.0/17 Alu = 17,4 kg
as you can see, the OEM rear wheel in particular is a whopping 13lb heavier than the Brembo from the Yamaha. The two together make for ± 17lbs reduction in weight, that is in rotating mass that has to be accelerated and decelerated.
That ain't peanuts.
add to that the highest quality chain available (DID ERT) and gain another 1-2PS otherwise devoured by the very stiff cheaper chains. Or go for a straightforward racing chain without seals if you only ride in clean conditions. You still haven't touched the engine or compromised its reliability.