stiglarsenDK wroteBuilding 2 more engines with the same recipe .. St4s w 996 sps left side...
I have sourced all the 996 (2000) parts and some RS flywheel, rotor and stators parts as well.
The RS flywheel is not having starter feature ... hmm .
Did some parts weighing and come up with -2.3 KG rotation and - 2.6 KG static, hence we are talking 5kg !
I'm tempted to take out the 5 kg as it's for racing ... I'll need a roller starter ... (if any advice here, please share does and don'ts
Ah Flywheels. Flywheels are an energy storage device that can double as harmonic balance to reduce inherant vibrabration. I've run a 250 with and without, and a 900 bevel with and without. What power you put in due to rotation momentum, you get back. So it's all about acceleration and deceleration time. I would suggest strongly the factory race bikes have a bead on this already and so wouldn't deviate from what they use.
There was a car guy on the net writing about lightening flywheels and his conclusion was as the power used to drive them was relatively small, they were the very last thing he would consider in performance enhancement. Considering how much torque your going to develop I doubt you'll be able to notice the difference. Of coarse a couple of dyno runs will give you the definitive answer.
My conclusion from running without on a 250 was the acceleration gain was relatively small, at the cost of increased vibration. Vibration itself saps power to a degree, and increases the chances of things becoming loose. Not to mention fuzz hands and feet and in the case of the 250 an uncomfortable sphincter (yep at 13000rpm it's nasty). This time on my twin i'm Going half way between zero and full flywheel, to reduce hand fuzz. (I have weighted clipons already)
Seeing how your looking at all of this, consider reading up on ceramic bearing. The good ones are expensive, but there are gains to be made as they can run closer tolerances because heat is not an issue. Smooth is fast.
As for using starter rollers, that depends on how much you value the cash you spend for track time, versus your desire to be Carl Fogarty. 😁 If it snuffs out for some reason like a run off, that's the end of your laps. At least you stand a chance If you can fire it up again out on the circuit. In hysterical racing forgetting to turn on fuel taps is rather expensive!
