29 inlet housing cap

[Mike Dix]

So close to having my 29 JD engine together. Discovered in my boxes of parts I have two different inlet housing cap assemblies. Neither have legible part numbers but I’m thinking the correct one is beefier and has a 5/16 pivot bolt for the rocker arm (inlet lever )The other one has a 1/4” dia. rocker arm bolt and smaller bushing. Parts book shows a 98-29 housing and a 105- 29 inlet lever for a 29 JD. Anyone have a couple of these ?

[exeric]

Over the history of Js, and JDs, intake rocker housings, and rocker arms changed a lot and the parts books don't detail those changes. If an updated part worked on earlier models, H-D considered that the correct part regardless of catalog pictures. I would go with the .312" pivot bolt, and corresponding rocker arm because the inlet housing assembly, and basic concept of it are the weakest part of the IOE Harley-Davidson engine.

[exeric]

I should mention that the threaded pushrods, and corresponding ends have to match the rocker arms.

[MMasa]

Yes, 1929 models used the "big axle" rocker towers and arms. The thinking was, I'm sure, to increase the load bearing area between the arm and the bushing. Note that 1929 has a one year only right side gas tank due to this rocker arm change.
The rocker arm cutouts in the tank have an additional clearance divot pressed into the top. This is to give added clearance to attach the grease gun end to the Alemite fitting on the rocker arm.
The arm and fitting will clear on the 25-28 tank.
Mark

[Mike Dix]

Thanks for all the info Guys. Off to Wauseon in a couple weeks to scrounge for parts !

[Mike85]

I have a '29 JD original. Is this something you can see from the outside? Happy to take pictures.