39' EL Break-in and Calibration

[dukekleman]

I have spent many hours over all the years in Dynamometer Calibration Test Rooms. However, due to their rarity, it's not everyday I spend time heat cycling, piston ring seating and calibrating old EL Knuckleheads.

While they have their own unique challenges, it's always a treat to work these...
IMG_20250604_171948133_HDR.jpg
A true classic.

Duke Kleman

[FrankD]

Beautiful looking engine

[gharper]

Great work Duke!!! I'm anxious to learn more!

[dukekleman]

Thank you Gene!

[dukekleman]

Engine Break-in Process and Goals...

The process of breaking in an engine is lengthy.
You are heat cycling the engine initially to introduce all the components, including gasketing to heat and oil while allowing time in between for sufficient cooling.
This is the beginning of the seasoning process the engine will see.
During this time, temperature is monitored, oil pressure is monitored and adjusted while observing any potential problems with gaskets. Any issues can be addressed quickly while in the room. Ignition dynamic timing can be observed as well as the AFR (Air Fuel Ratio) . The engine can be shut down immediately if necessary to make static corrections or done dynamically while running.

Here's an image of the engine running initially, setting idle speed, monitoring fuel calibration, temperature, oil pressure,
Charging system voltage and KV output to each cylinder.


So sometimes the question is asked, what are you actually breaking in?
The short answer is the piston rings to the ring lands in the pistons and the cross hatch in the cylinders.

Cylinder preparation, cross hatch angle, RVK and RPK are critical and set during the machining processes performed.
This is what your seating, asking the piston rings to shape themselves to.

Depending on how the cylinders were machined, this process of ring seating can occur quickly. As this is the goal. Proper oil retention in the RVK along with correct AFR's to prevent fuel dilution of that oil in the RVK area is critical and what break-in is all about.



Verification of oil to critical areas is done during the build process in various stages. During engine Break-in, you are simply monitoring your dynamic pressures.
Bearing races that are line honed, line lapped and the dimensions measured with a dial bore gauge are not as critical during the break-in process due to roller bearings verse piston rings.
Nor are the following components and areas shown in images below. As long as they are sized correctly and concentric.



The main concern with these parts during engine Break-in is proper oil supply, immediately and heat control observation. Monitoring this can be done effectively and the engine shutdown immediately when certain parameters are met.

As all engine builders know, there is a lot of work involved in this series of engines. Although much verification and documentation is done during the machining/build process,
a little bit of anxiety and a lot of excitement occurs during the Break-in and Calibration stages prior to the celebration, laughing...

I hope this helps,

Duke Kleman

[FrankD]

Duke, thanks for explaining the break-in procedure, I found it interesting. Also, having the ability to monitor and adjust a fresh engine in a controlled environment is ideal. Glad you are helping to keep these old bikes on the road. Frank

[dukekleman]

Frank,

The Test Room does have its safety benefits for the operator and the motorcycle.
I've spent many years doing open road calibration and Break-in work. Magnetic Tank bags and back pack full of Data analysis equipment. Many times you find yourself not looking at the road, head down looking around on the motorcycle or the equipment you have attached. Point being you are distracted.
I do this yet but not at the same extent with less equipment attached. I start initially in the Test Room and finish on the street.

As for the motorcycle safety, I like that I can exit a test very quickly, verse trying to pull over or turn around and drive back to the shop. This way you don't have to travel back with Data numbers that aren't ideal for the new engine, gasketing issues leaking, etc...
Tooling is easily available in the test room and high speed adjustments are safely done as well.

I have written recommendations for ring seating procedures for on the road. I supply these to shops/customer's that pick up the engine only verse an entire motorcycle.

Duke Kleman