Break-In Oil

xbacksideslider said:

So . . . . there may be a conflict between what engine speed is optimal for a breaking in a cam versus seating piston rings?

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Not really.
I just stick with
-start it and run it around 2500 until I feel heat in the barrels and then ride it with heavy throttle but short shifts for 1/2 hour before I let it idle. After that the sky is the limit.

It's obviously easier to do on the dyno. Jim

What Jim says.

You can have your cake and eat it too. No reason you cannot take it immediately and keep RPM up while loading and coasting (cooling) then loading again. Keep the rpm up to assure full hydro dynamic on the cam while loading and bedding the rings and letting them cool a bit before doing it again.

I have personally seen new camshafts destroyed in 1500 miles due to improper break in. I have no idea what Norton recommended but if you are replacing the camshaft, I can't imagine that the cam maker won't recommend at least 2500+ rpm for 20+ minutes. Cams are the most critical component in that regard for an engine rebuild. You can't really damage anything else by doing break in "wrong" though it's possible to get less-than-optimum ring seating.

Of course, if the original cam/original lifters (in their original positions!!!!!) are being used, and you just did new bearings/rings,etc. there is no camshaft break in requirement at all.

Heres' a link to comp cams video of the recommended process. It's pretty much the same as any camshaft company's recommendations… https://www.youtube.com/watch?v=re-VqHO ... e=youtu.be

Almost all my handful of intial runs in occurred well after dark so for Trixie I rationalized after smoke cleared within mintures and a few more start runs checking adjusting best not to trush blower to cool like rding so I changed oil retorqued kicked off straight over 2500 snick 1st and stay mostly above that getting to pavement so I could stay over 3000 no problem for 20 min. done before turning back for home. If it good for intital run in then its good ther after. Legend has it that best run in are done on a few race track laps before an event. Do not miss opportunity to twist check cradle to head fasteners til a few extra times unneeded just out of habit.