I have been asked by several people to expand in more detail the work required to convert a J model Harley roller bearing neck to the tapered Timken bearings we installed on my Cannonball Motorcycle. I would be more than happy to share the details we experienced while machining these cups. Plus, I will include some detail photos of the project.
As you will see, the factory cups for the fork neck on early J model Harleys (1911 - 1921) held 40 - 1/4 inch (.250) roller balls. 20 balls in the upper cup and 20 balls in the lower cup. These balls get wear and develop flat spots on the rollers, which cause a sloppy front end, speed wobble and just stiff turning. For the Cannonball project bike, we decided to install Timken tapered roller bearing in the neck of this 1919 Harley. This conversion is quite common on motorcycles with the ball bearing necks, but no one we found offered the proper cups to fit an early J Harley.
After knocking out the original cups with a brass punch and hammer, inspect the neck and clean all edges.
The factory measurement for the neck height is 5 1/4 or 5.258. At this point, we also decided to install a complete VL I-beam front-end on this bike. All components will exchange. This also allows me to install a front drum factory VL brake setup without any modifications.
Here are some detail shots of the actual bearing cups we machined to hold the races and tapered timken bearings
Timken Race Part # 15520 - sug retail $8.43
Timken Tapered cone bearing Part # 15590 - sug retail $16.28
Here are the measurements for the race holders - Top and bottom cups are exactly the same.
Use a threaded rod with large washers to squeeze the cups into the neck.
Here is the VL fork installed in the J Harley neck with tapered neck bearings.
Hope this is helpful. I have not ridden the bike with this frontend yet, but plan to have it back together in the next few weeks, so we can start to test and adjust it as we continue to press forward on the Coast to Coast Run in 2014 - Thanks
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