73 JP Frame Design

[linglewn]

I recently completed the rebuild of a 72 JP (Aug 72 build date). It, of course, had a non-breather frame. I just picked up a 73 JP (March 73 build date), and much to my surprise it has a breather frame. The production guide indicates that there was no frame change from 72 to 73. Do any of you folks have experience with both types of frames being used in 73?

Also, the production guide indicates that black cast magnesium barrel hubs were used in 73. Mine has the older cast aluminum hubs. I realize that there is no definite model year change date, but it seems that March should be well into the model year. Any experience with Magnesium vs Aluminum hubs on 73 models?

Thanks for the help.

Nelson Lingle

[Chakka]

Nelson,

Back in the late 70's I owned a Jackpiner just like yours. It had the alloy hubs and the earlier style rear wheel set up (pre-conical) with the seperate sprocket carrier and drive cusions. It was also a frame breather. I always suspected it was made early in 73'.

Chris

[Lew Mayer]

Me, too. My 73 has a frame breather and non-conical hubs. It was actually titled originally as a 74.

Lew Mayer

[Mike Lenz]

There was a frame change in early 73 to the frame breather.  Mine also had the alum hubs. Pretty common I believe, at least for the early 73's.

[Kip Kern]

I have and raced (at Tulsa) a 1973 stamp dated Jackpiner with a non breather frame, aluminum fenders too;)  Always expect the unexpected when it comeds to Pentons:D

[linglewn]

Thanks for the responses. Before I started the restoration, I just wanted to make sure that I didn't have some sort of half-breed.

Nelson