Breaking in newly rebuilt engine

[top-jelopy]

Hello , I'm looking for opinions/methods on the best way to break in a newly rebuilt rd400 motor. what oils to use? speed/rpms  to reach etc . Thx

[SUPERTUNE]

It can depend on the builder...Who did the cylinder boring? What type of piston/brand was used? What piston clearances were used? What grit honing stones were used for cylinder wall finish? What oil was the engine assembled with?

I have developed my way over the last 30 years to get the results I need with new engines to last.
Look at Guillermos Dyno runs...this was done after he put 7600 miles on it, with nothing but new plugs and fixed a junction throttle cable splitter block, still a strong horse.  Yes I'm tooting my horn, but I earned it...
I use racing synthetic oil right off the bat, I also have re-shimmed up the pumps and use fat break in jetting and I run them in fairly hard, but real brief blasts to seat the rings and use wide open throttle to use fuel from the main jet to cool the engine as well.
I'm pretty much done with breakin after 125 miles on hot rod RD's.

Chuck