Initial engine start-up ?'s

I am at the point of starting a partially rebuilt engine for the first break-in period. By partial, I mean only rings/honing and con-rod bearings. New lifters were installed but nothing else camshaft related. Valve grind and seals.

I have read on this forum that the inital break-in should involve 20 minutes at 2000 rpm. My machinist said he didnt think 2000 was necessary because we didnt do the whole meal deal. He thought 1500 would be fine. Any opinions? (Like I dont know there will be any opinions, right?)

Also, is it okay to do this initial break-in and then not start it again until I am ready to do the road thing (setting rings by 30/50/30mph X 10) or does it need to be done immediately following the initial high rev break-in?

It may be a month before I am able to get it on the road, but want to see if there are any further engine issues that need attention.

No doubt you'll get varying opinions. I think you're fine waiting between. Just make sure you prime your oil pump prior to both starts.

Morning John, take a look at this,very good info.

http://www.mototuneusa.com/break_in_secrets.htm

I break in all my racebike motors the mototune way and the difference is amazing when the motors are pulled apart.

Seal them up good initially when they are doing their first heat cycles! because if you break it in slow,,, slow is what you are going to have.

Jay

The big thing when using the mototune method is to make sure that the cooling system is working correct so that the engine stays within normal operating range. It is necessary to have the ignition, carbs and valves set spot on.

After around 200 miles re-torque the head and check the valve lash and tune.
It would not hurt to change the oil and filter at the 200 mile mark. I strain the oil thru a coffee filter to check for what is in it.

We used this method at the Honda dealer that I worked at in the early 70 s with excellent results.

what about the method of running the engine at 5,000 rpm's and allowing it to slow down by decelleration 4 times? i guess that counts as running hard. i'll be breaking one in next month.

The 2000rpm for 20 mins is for bedding in the cam. Since you did not touch that you should be fine to proceed to the next stage of varying loads as mentioned above.