Well I would not have believed many people regarding the effect of a balance shaft being that great, but Mr Thiel I bow to any day of the week.
My comments were based around " needing " a balance shaft , and yes it is a fact that a well balanced 125 , up to 14500 rpm , you cant tell ( feel ) the difference.
But I think I have mentioned before - Dr Fleck at QUB discovered very early in his distinguished time there that the same engine made more power on a dyno with more inertia.
He instrumented the thing and discovered what was then a completely new phenomenon.
More inertia , be it the dyno flywheel or tunsten in the crank wheels , reduces the in cycle speed variation of the crank assembly.
Thus at BDC the crank has not accelerated as much from gas pressure on the piston , and in effect gave the transfers more time ie the all important STA number.
This is a Catch 22 scenario . Up to a certain point the increased inertia adds more power , but then it soon becomes offset by the increased power needed to accelerate the greater mass.
Its a critical system where a small change can tip the effect in favour of each end result quite dramatically.
This was proven again later in 125 GP racing where Honda offerred an A kit option of removing the flywheel and replacing it with just a timing trigger disc , just running total loss battery.
People tried to do this to a standard RS125 , but sadly without the much higher inertia factory kit crank , big fail - no peak or overev Hp at all.
HRC and VHM then offerred a high inertia crank for total loss , but in reality the total loss system had no advantages as the power lost due to the spinning magnetic field needed for the ignition was minimal.
So - In Jans case with his 125 experement , the addition of the balance shaft put the overall inertia closer to optimum . How much power was gained from lower resultant vibration we will never know.
Re greater power loss from CNC cases Vs sand cast . This is easily answered . If you take a lovely looking CNC case and steel shot bead blast it, making the surface look just like a sand cast one - the power is identical.
Speckly surfaces radiate more heat due to more area.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
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