Frame Dimension - - help?

[bmh]

Thanks very much for the reply. I have no way of knowing the actual production number of this frame, or even if it is for sure a '52. I bought it by itself, just the frame. It came with a combination of features that would have identified it as either a '48-'51 or a '52. Certainly no later than a '52, based on the lower front motor mount.

Since I was going through all my frame notes, I thought I would point out that very late 51frames and 52 frames have a unique front motor mount. it is similar to the earlier one except that the valley formed on top has been filled in. I believe this was replaced in53 with the same mount used from then on with a solid mounting pad rather than the hockey pucks. The late 51 frames did not use the new top mount introduced in 52. Sadly these features do not photograph well on assembeled machines so all I have are my notes to go on.

[Steve Little]

Hi Brian.
The centre back edge of these late 51-52 engine mounts are still hollowed out as well as the centre top section.
The area outside the engine mount pads are filled in for strength.
If a bike is assembled with an engine and you want to identify a frame, they can still be identified by getting a torch and looking past the back edge of the brake pedal. The hollowed out back section of the engine mount can still be seen between the cases and the bash plate.
My 51 has the engine out at the moment so I can take a pic if needed.
The factory took a long time comming to the conclusion that they needed to beef the front engine mount up. I have seen a lot of Knuckles with the left side of the engine mount broken or welded just outside the left pad.
Or maybe the hellish brute horsepower of the new 52 Pan was the the reason.
Regards Steve

[Rooster]

I would like to correct my previous statement, in going through my photos and notes I found that 52FL255X did have the rounded mounts. Here is a pic of that, they appear to be the same thickness as the square variety.

I am looking at this photo, and although the horn mount blocks may be correct, very little about the way the horn is mounted is correct. The bolts aren't even close to being right, with the correct bolts and the lock-tab bracket both absent; looks like someone used whatever was in the junk drawer and used washers as spacers to keep them from bottoming out. Also looks like the tension spring is gone, and can't tell about the little 'sleeves', but they seem to be absent too. It looks to me like this is a temporary roadside fix that never got corrected.

[Rooster]

Hi Brian.
The centre back edge of these late 51-52 engine mounts are still hollowed out as well as the centre top section.
The area outside the engine mount pads are filled in for strength.
If a bike is assembled with an engine and you want to identify a frame, they can still be identified by getting a torch and looking past the back edge of the brake pedal. The hollowed out back section of the engine mount can still be seen between the cases and the bash plate.
My 51 has the engine out at the moment so I can take a pic if needed.
The factory took a long time comming to the conclusion that they needed to beef the front engine mount up. I have seen a lot of Knuckles with the left side of the engine mount broken or welded just outside the left pad.
Or maybe the hellish brute horsepower of the new 52 Pan was the the reason.
Regards Steve

Steve, I don't mean to intrude on the thread, but perhaps you can help here; I believe the motor mount in this photo is of a 1952, which according to Mr. Palmer, is a one-year only mount. Can you confirm this? Notice the 'filled in' portion of the mount on either side of the motor pads. The photo is of a motorcycle I bought which 'may' be a 1952, as it had a 1952 motor in it. But so many things were incorrect on the bike, there's no way of knowing if the frame is original to the motor, or not.




As a comparison, here is a photo of another frame I purchased, year unknown. I had thought it was a '52, based on what I thought at the time to be the 'lighter' front motor mount, and the presence of a 'horse-shoe' tool box mount bracket, 1952 being the first year it was introduced. However, I have since determined that although the toolbox bracket is an original HD part, it had been welded on the frame in an incorrect location, being some 1-1/8" too far aft. Therefore the logic that the frame is a '52 is defective, and the year of the frame is still unkown.
Would you say this mount is on a frame that is prior to 1952?

[bmh]

Rooster, to me The lower picture is of the earlier style mount. The top would be the late 51 -52 version. The later versions are filled solid at the mount pad. As far as the 52 I pictured with the rounded mounts, the frame and motor appear to be a match. As for the mounting hardware, you should've seen some of the other stuff. The owner rigged his own turn signals up outta stuff from Western Auto. But needed more resistance to get the flasher to work correctly..... so he wired 4 extra bulbs up and stuffed them in the tool box. Definitely a what ever worked at the time kinda guy, he's owned it since the 60's.

[Rooster]

Rooster, to me The lower picture is of the earlier style mount. The top would be the late 51 -52 version. The later versions are filled solid at the mount pad.

Yes, I agree with that. Thanks.

[Glenn]

my 1950 all original frame is apart if anyone need any pictures or measurements