Engine break-in

[Wbergt]

Hi
I so pleased this site is back. There was a post on the older website that gave specific instructions for breaking in a rebuilt engine. Could someone repost this procedure? I would greatly appreciate it
Thanks Bill

[SUPERTUNE]

It's like an oil question... all engine builders have their ways about doing the break in.

A lot of it can depend on how stock or modified the build is, mainly type of pistons used and piston to wall clearance used.
Some builders like to put them together with tight clearances, then after a easy break in time of running, take it back apart and sand off high spots on the pistons. Just not for me.
I like wide open throttle in brief hits in the first 4 gears or so after a 3-5 mins warm up, Rev it to 1500 below your normal redline.
Main jets control the fuel amount and in an air cooled engine control the heat in the piston crown. Full throttle gives fuel needed to cool piston and seat rings. I want the main jet in full effect.
I want the rings to seat right away, So I like high cylinder pressure by hard brief loads.
After a half of tank, then go normal riding for the rest of the tank staying off the long highways or interstate where steady throttle is used,  very'ed throttle is the best.
This is my Opinion Only and the way I do it. 

Chuck

[Wbergt]

Thanks Chuck
This engine is a stock overbore to 64.5 with ProX pistons. Stock specs. I remember a sheet one of the engine builders (possibly Lynn Garland) sent with either his engine or crank rebuilds.
Regards Bill

[Plasticman]

It's like an oil question... all engine builders have their ways about doing the break in.

A lot of it can depend on how stock or modified the build is, mainly type of pistons used and piston to wall clearance used.
Some builders like to put them together with tight clearances, then after a easy break in time of running, take it back apart and sand off high spots on the pistons. Just not for me.
I like wide open throttle in brief hits in the first 4 gears or so after a 3-5 mins warm up, Rev it to 1500 below your normal redline.
Main jets control the fuel amount and in an air cooled engine control the heat in the piston crown. Full throttle gives fuel needed to cool piston and seat rings. I want the main jet in full effect.
I want the rings to seat right away, So I like high cylinder pressure by hard brief loads.
After a half of tank, then go normal riding for the rest of the tank staying off the long highways or interstate where steady throttle is used,  very'ed throttle is the best.
This is my Opinion Only and the way I do it. 

ChucK

The process Chuck outlined is how we used to break in our new endurance road racing engines back when I ran WERA/CMRA.

Rob

[rodneya]

Rebuild wet or dry?
Seems a lot of people like to put the top end together dry so that there is not a lot of extra oil to glaze the cylinder

[Seizer]

I wiped my cylinders with an oil saturated paper towel as I assembled. No issues.

[SUPERTUNE]

I assemble my engines wet, mainly due to the special Sunnen honing setup I use.
I use special stones made for honing keyway bores, they are the trick setup on 2 stroke cylinders and have extra sets I just use for RD bore sizes!

They are the YY stone sets, They use double guide, double stone per each side. They hone to perfect size, perfectly round and give finish I want using that expensive MB30 Sunnen honing oil!  $30 gal.
I'll see if I can find some pics again...this info I posted before was lost in space when the other site went down.

Chuck