Author Topic: 42 or 47  (Read 1527 times)

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Offline ridgerider

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42 or 47
« on: February 23, 2015, 07:32:36 AM »
are there visual differences in 42 or 47 knuck cases other than the numbers?

Offline Speeding Big Twin

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Re: 42 or 47
« Reply #1 on: February 26, 2015, 04:12:51 AM »
According to Matthew Olsen, the serial number boss on cases for 1942–43 and some 44s has a recess at the bottom where it meets the radius of the case. He also said there is a minor difference in the case casting at the cylinder base (front left). Matt mentioned these things on his blog in December 2010 and provided some photos. I posted two links below.

However, I’m not sure that the recess at the base of the number boss is restricted to the years Matt said because I went through my serial number photos and some 1946–47 cases appear to have a recess. Maybe the recess on 42–44 cases is more pronounced than on 46–47 cases?
 
What is it exactly that you are trying to sort out?
Eric

http://oldbikesinsd.blogspot.com.au/2010/12/early-knuckle-case-pics-and-motor.html

http://oldbikesinsd.blogspot.com.au/2010/12/aluminum-pics.html

Offline ridgerider

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Re: 42 or 47
« Reply #2 on: February 27, 2015, 02:49:08 PM »
thanks for the reply i have knuck that i bought in the mid 70"s rode it for years, have had it rebuilt 3 times blew apart twice once bad rod bearing 2nd 61" cylinders bored to 20 over 74" that rebuild lasted 200 miles. had the cases welded and machined a few years back  looking through my paperwork--winter here not much to do--- i notice 1 of the shops listed it as a 42 not a 47--turning 60 this year and going to have it rebuilt again i think, or give up and sell the parts trying to figure out exactly what all i have.

Offline Speeding Big Twin

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Re: 42 or 47
« Reply #3 on: February 28, 2015, 01:26:37 AM »
If it’s a 47 engine then I imagine a shop would normally go by the serial number so if it got listed as a 42 then maybe it was just a typo? Can you post a photo showing part of the serial number. And what about the belly numbers? Or were the numbers damaged when the engine blew apart?

For 1942–47 the Knuckle left case would normally have casting number 112-406 and the right-hand case usually has 112-404. And normally there are also date codes to indicate month and year of casting. Are date codes still present?
Eric

Offline ridgerider

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Re: 42 or 47
« Reply #4 on: March 01, 2015, 07:33:02 AM »
the 1st time it blew on me the a rod went through the bottom of the cases shattering it , the second time the cylinder blew taking off the top of the cases and through the number boss. pretty sure not original cases at all ...maybe replacement halves form prior to the 70's i was told harley sold replacement 1/2's through the 60's the heads are 74" for sure, the bottom end was 74" had a bad left wheel so builder pution 2 right hand wheels. the odd part is it had 61" cylinders bored to 74" +  the tranny is a panhead ratchet lid it was all in a 47 knuck chopped frame, i think,, no numbers on a frame i know of..with a 27" over springer.

Offline Speeding Big Twin

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Re: 42 or 47
« Reply #5 on: March 01, 2015, 08:24:39 PM »
If they are repaired cases I’d expect to see some sign of that and there may even be part of the BN still visible underneath. Most, but not all, Knuckle BNs were originally formatted similar to the following example: 47-1234.
 
H-D sold replacements as halves and as pairs but at some point the factory stopped supplying a new SN-side case unless the original SN-side case or the piece containing the original SN was handed in. Some replacement pairs didn’t have normal BNs but still had ID to indicate they were matching—for example, the replacements below have 1947 date codes inside but they have 43 stamped underneath to indicate they are a matched pair:



Is anything stamped anywhere on your cases? And do they have date codes and/or casting numbers? If you post photos we may be able to figure out what happened.

Replacement left cases sometimes had the SN applied by the dealer but on occasion the stamps weren’t consistent with the year and/or model of the original machine. It seems that at times the dealer used H-D stamps from an earlier era but on other occasions he may have used AM stamps. If you post a photo showing part of the SN we may be able to give an opinion on what stamps were used.

If the trans case is 1948–early-64 Panhead it should have CN 121-35 underneath. Later-64 Pans had CN 34703 64. For obvious reasons it’s probably unlikely to be a 65 trans but if it is then the CN would be 34703 65. Most, but not all, Pan trans cases have a date code underneath. What date code does yours have? Pan trans cases 1962-later have additional original component identifying numbers stamped on the front.

H-D used at least two different types of ratchet lids for Panheads. Very late 1951–58 has no provision for a neutral switch but the 59-later ratchet lid does.   

No H-D Knuckle frame originally had a frame number. They do however have forging numbers on several pieces. And you may find ID stamped near the top of the seat post tube area if the frame was ever sent to H-D for repair.   
Eric