Do you have to shim motor mounts on every bike?

[Panhead_Bobber_11C]

I'm putting together my 49 panhead right now and noticed unlike my 2 knuckleheads there is no gap on the front motor mounts that need to be shimmed.i tightened down the rear 2 bolts and the 2 front mounts of sitting completely flush onto the frame. I dont need to shim then right? Becuase I hear Horror stories of guys not shimming and they crack a case.

[Jerry Wieland]

In a nutshell - yes. Usually the front mounts need to be shimmed. If after tightening the rear motor mount bolts you cannot get a shim under the front then you need to remove the rear bolts and put bolts in the front mounts and check to see if the rear mounts need to be shimmed.

This procedure really should be done with empty cases and not a full engine.

I have found very few engine that do not need to be shimmed.

Jerry

I'm putting together my 49 panhead right now and noticed unlike my 2 knuckleheads there is no gap on the front motor mounts that need to be shimmed.i tightened down the rear 2 bolts and the 2 front mounts of sitting completely flush onto the frame. I dont need to shim then right? Becuase I hear Horror stories of guys not shimming and they crack a case.

[larry]

What frame do you have?

[T. Cotten]

Panhead Bobber!

Please inspect the bottom decks of the cases where they rest upon the frame. Often they are worn or eroded,

Welding and milling is required for severe cases, and still must be inspected for shimming, as frames 'flex'.. For lesser wear or blemishes, epoxy can "bed-in" cases upon the greased frame, or even shims.

Most commonly, the rear is secured, but the front is not tightened until the epoxy has cured.

....Cotten

[Panhead_Bobber_11C]

In a nutshell - yes. Usually the front mounts need to be shimmed. If after tightening the rear motor mount bolts you cannot get a shim under the front then you need to remove the rear bolts and put bolts in the front mounts and check to see if the rear mounts need to be shimmed.

This procedure really should be done with empty cases and not a full engine.

I have found very few engine that do not need to be shimmed.

Jerry

I know. I have owned alot of bikes and allways needed to be shimmed. I got a 60 FLH motor in a 54 straight leg frame. I did common procedure and the front mounts did not rise up even a little it sat totally flush after I tightened the rears. Also on my stock 49 original motor and frame does not have shims and that motor has never been taken off that frame. Harley also didn't shim at the factory either from what I can tell. Not sure ♂️ unless I just got lucky.

[Jerry Wieland]

My thought on original bikes not ever having shims is that when the cases and frames were first made the tolerance was close enough to not need any but with use things change.

Jerry

I know. I have owned alot of bikes and allways needed to be shimmed. I got a 60 FLH motor in a 54 straight leg frame. I did common procedure and the front mounts did not rise up even a little it sat totally flush after I tightened the rears. Also on my stock 49 original motor and frame does not have shims and that motor has never been taken off that frame. Harley also didn't shim at the factory either from what I can tell. Not sure ♂️ unless I just got lucky.

[T. Cotten]

Please consider, Folks,..

Let's assume they all started out "level", but a couple of generations of pounding road stress upon the headstock transferred through the spine of the frame until the seatpost tilts ever so slightly backward. It is easy to see why the gap so often appears upon the front mount.

Metal moves.

...Cotten