Cases

[Robert Luland]

There is a set of for 47 FL Knucklehead cases for sale and in one of the photos the left front motor mount has the letter G stamped on it. Anyone know what this is? Bob

[Chris Haynes]

There is a set of for 47 FL Knucklehead cases for sale and in one of the photos the left front motor mount has the letter G stamped on it. Anyone know what this is? Bob

Bad numbers

[Robert Luland]

Not the vin Chris.

[Chris Haynes]

Not the vin Chris.

That means somebody had a G stamp they wanted to try out.

[Jerry Wieland]

These cases are not even knucklehead. If they are a factory matched pair they are mid production 1948 pan that have a 47 number put on them.

Occasionally numbers/letters are seen stamped on cases and I doubt if anybody has a good answer for them. I have always assumed that they were inspectors stamps or something similiar.

Jerry

[Rubone]

Many years ago I used to stamp my own initials on any bikes i built with the intention of keeping for a while. In the '60s and '70s bike theft was BIG and i considered it a deterrent. If anyone has a knuckle or pan motor with an RK behind the lifter blocks it was mine at one time!
Oh, by the way, I no longer do that!
Robbie

[bmh]

Jerry, how did you spot these cases to be mid year 48 production from the photo posted? Enquiring minds need to know.

[Jerry Wieland]

BMH

When HD was tooling up for 1948 they added the necessary changes to the case molds to accomodate the panheads but they did not at first delete the traits of the knuckle cases. This left distinctly early and late style cases for 1948. Through observation of OEM 1948 matched cases and bikes I have noticed that the change to the later case seems to have happened earlier on the right side than on the left.

The first picture of the bottoms shows one of the distinct differences between early and late 1948 cases. Look at the radius of the outer edge - the late cases are very squared off and the early ones are rounded like knucklehead.The 2nd pictures shows the tappet area of a knucklehead. The 3rd picture shows the tappet area of an early 48 case. The 4th picture shows the tappet area of a late 1948 case. Early 1948 right cases have the boss for the knucklehead style timed return breathing but they are not machined.

In the picture posted by Robert the right case is very distinctly later 1948 and up and the left case is distinctly early 1948 and down - possibly including knucklehead. However there is a 3/8 inch height difference in the front motor mounts starting in 1948 and I do not believe that this difference exists here so I assumed that these are both pan.

If you could look at the tops of these cases I am sure that you would observe the return oiling grooves in the cylinder base and also the added aluminum above the serial number to accomodate them.

Hope this helps. Jerry

[Lonnie]

The '48 I restored had the early right case, It looked almost identical to the knuckles in the area above the oil pump. Distinctly different from the later '48's.

LC

[Jerry Wieland]

Lonnie My 1948 which is 48FL788x actually uses the early cases but yet I have seen a matched set of cases with 4000 some serial number have the later right. Doesn't really make sense.

Jerry

[exeric]

Wow Jerry, what an eye ! I checked the cases on my '48 motor and they are rounded, S.N. 48FL29XX.

[Snakeoil]

Just thinking out loud here. I would suspect that replacement cases for knuckleheads were made after the engine went out of production for bikes. It might explain why early pan cases had both knucklehead and panhead features. One size fits all mentallity. Only need to cast one type of case. When enough spares were made, and the molds were due for replacement, that might have been the point where the case design changed for future production.

As pan motors were built, I would think that there was always the chance that case supplies might have been interrupted and the stock supply of replacement knuck cases was raided to keep production going until new pan cases could be supplied.

I'm sure there are a number of other scenarios that would account for illogical case half matings and serial number discontinuities.

[bmh]

Thanks for the education, now my whole day wasn't wasted ( just everything up till I read that post). I was never aware of that progression of changes.

[dommi7]

My '41EL case has the same "G" on the front motor mount, although mine is on the side of the motor mount (around the corner toward the drive shaft).
No idea why it is there, nor what it means.

[Robert Luland]

I went out to the shop to day and my numbers are 48FL759X and both cases are square. The belly numbers on the other hand lead me in a differant direction. The left case numbers are much duller than the right. Got a feeling that the right case was replaced at some time. Thanks Jerry. With out your post I've probaly never had even looked. Bob