The 71.25mm pistons earlier used on this bike with 1005cc billet block have got additional holes.
Top ring gas ported.
I'm eager to test them. But no plan today when and which engine.
The 970cc it has now work really fine.
Maybe high compression that might be more visible with correct needles (leaner).
Low - middle range is much better, snappier response when running not that rich as before.
I heard a strange sound after 7000rpm something during a snappy handling of the throttle on 3-4 gear unleashing the fun power yesterday.
I have retarded ignition one pen strike, rotated plate 1mm clockwise at the outer edge.
I'll try and hear if I can repeat it.
If not, ignition back as it was and test again.
If sound comes back with ignition as it was, I'll try some chemistry. Add a little toluene, xylene or similar in the fuel, highest tap octane available here, Shell V-Power.
Or, retard ignition a little if not retarding the fun.
I've heard about very small amount toluene in the gasoline to avoid pinging.
Paint dilution stuff
I really do not want to go for thicker head gasket, increasing chamber volumes 0.962cc with +0.25mm MLS removing the fun.
EDIT:
Why not verify the ignition?
I did and found that I could retard it so F is spot on case mark at idle as usual.
Checked both 1:4 and 2:3.
Too easy to only check 1:4.
(The 1:4 sensor might have been changed/moved.)
Both spot on.
EDIT 2024: Returned to almost as it was, advanced a little. The pinging heard was due to main jets. The shorter Hindle muffler need one step up from 142.5 to 145. The correct leaner needles can be involved too.
Last time setup according to earlier settings marks. Blue pen.
Advancer must have been in in its most clockwise position of its play, ignition set against stock case mark, not to the additional later marking for clockwise position when blue marks were done.
The most clockwise position of advancer used when timing cam. An extra case mark 3mm after done at real TDC.
Green mark at setting today.
#
But engine loved the advanced setting before 7000rpm.
Would be nice with an ignition I can set my own adv curve. As my advancer with cut springs worked when advanced, but a little retard after 6000rpm. If that will be correct. Might be.
Buy an Ignitech ignition with new coils might be something.
Or solve it with real fuel, >102 octane instead of 98+ V-Power.
(Maybe V minus power? )
I have to verify when I touched the ignition last time.
I got a stange +3whp on dyno late October. The advanced setting worked with the rich jetted carbs.
It would be better if gas stations have Diesel, low octane gasoline for low tuned/compression engines and >102 for tuned ones.
No fake additives produced instead of making food.
Nitro is a good additive!
Can be added at the pump, just press a button of % mix.