Do not run engine too slow.
There is a small window when bore surface is rough and can grind rings to seal.
Start and ride it carefully up to max 4000 rpm until engine is warm.
Throttle off from 4000 rpm a few times.
After a ca 30 minute ride continue to 6000 rpm bursts followed by throttle offs, engine braking which is said to cause harder ring pressure to bores.
A 50 km ride like that ready to give 6000-7000 rpm burst
This is fun. I could not stop the throttle before 8000rpm after 30-40 minutes!
I have noticed that a modified CB750 always need to be fully warm until full throttle for max acceleration. Clutch need to be warm.
Also double check clutch levers for play, not too tense.
Good idea to handle a stock buke öike that too.
I checked the lever inside clutch cover too at first run after clutch assembly to ensure play.
I have got clutch slips when too tight.
I have old Action Fours 65mm pistons to look at that got an easy break in. Not over 5000rpm the first 1000km. Brown residues under rings.
They do not seal as good as a set of RC 65 mm pistons with harder break in. Bores were not tight for the RC pistons either.
I remember I passed a friends car when getting a wheelie surprise when passing him in 70-120 kmh on a narrow bumpy country road at my first ride.
My first ride on that bike since almost 24 years felt good and happy I had the wheelie reflex to slowly release throttle to get front wheel down followed by full throttle! What a nice kick!!
The 4-1 was the screamier type.
