As a motorcycle enthusiast I’ve owned several Harley Davidson and yes Kawasaki’s as well. I sold my 2000 night train and purchased my first bagger a new 2005 FLHT. I clocked 36,000 miles when I noticed a vibration on my floor bard and an abnormal vibration at idle. The vibration didn’t feel as bad while I was rolling along. I went through the service manual and it pointed to the oil pump. So I took the motor apart. Upon inspection the pinion shaft showed excessive wear and both pistons and cylinders were scored.
So I decided to build a 103 inch motor. I ordered a SE flywheel, SE bearings, pistons, cylinders, oil pump and began to rebuild my motor. To my disbelief, the engine had another catastrophic engine failure at 31,000 miles.
When it happened the second time I began to question HD mechanics.

1. How much torque can the HD Flywheel take before it fails?
2. What causes the flywheels to fail?
3. How do I fix the problem?
Nine out of ten recommend that I weld my crank to eliminate the problem.
Not convinced with their recommendation I began to search the web for answers.

I found the answer to question 1 on a YouTube video called “How strong are your flywheels” Stock HD wheels fail at 2496 Ft /lb and S&S wheels fail at 5400 Ft/Lb.

Answer to Question 2 found in the following sites:
Hot Shots Motor works
• http://www.hotshotmotorworks.com/didja_know.htm
Power Glides
• http://www.powerglides.co.uk/ar/har_twi_cam_tech.php
Harley Flywheels rebuild true
•
You will note a welded S&S flywheel still failed.
All the information reviewed recommends re-installing Timken bearings on the flywheel.

To further understand bearing changes I looked up OEM part numbers.

2002 FLHT last year Timken bearings used:
• Bearing Part Number 9028

2003 – 2005 FLHT First Bearing change
• Bearing Part number 24604-00C

2006 – 2013 FLHT 96 and 106 inch motors/second change:
• Bearing Part number 24605-07
• Bearing Kit Part Number 24004-03B

The SE lefty bearing kit contains the same bearing Part Number 24004-03B
I’ve come to the conclusion Timken bearings control the lateral movement of the output shaft created by the torsional vibration inherent in HD motors thus reducing flywheel failure.
To prove my point I did not weld my SE flywheel.
I took my cases to Hi Tech Custom Cycle Holliday Florida 34690 (hitech8@tampabay.rr.com) an old school bike shop and Ross Mullen the owner installed the sleeve, Timken bearing and SE flywheel.
I picked up the bottom end, and completed the build with the following:
SE hi flow oil pump and support plate with hydraulic cam chain adjusters.
SE 204 cams
96 inch motor

Stock heads with larger valves and compression relief valves
SE sure fit push rods

To date I clocked in 2300 miles and the bike is running great.