Belly Number Research

[hennesse]

We're currently researching how the motor serial number ("VIN") correlates with the motor belly number on K's and Sportsters. But we need more data.

Please help us out by writing down your serial number and belly number(s). Email to: [email protected] or use the private message system on this forum. We won't publish your name.

Serial (VIN) number:
Belly number(s):
Do the belly numbers match?
Comments about your engine?

Thank you! The Technical:Numbers page needs to be updated, and your information will be used to make it more accurate.
Dave

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You probably won't be able to see the numbers by sticking your head under the bike. You need to gather the right tools.

Wait until your wife is out shopping. Then sneak into her bathroom and borrow the hand-held mirror she uses when doing her makeup. You'll also need rags and brake-kleen or some other degreaser, since the bottom of the engine is a greasy, oily mess. A flashlight may be needed too.

The numbers are on the bottom of the motor, between the oil drain plug and the lower front mounting bolt. When the motor is in the bike, the number on the right case is between the frame tubes. The number on the left case is on the outside of the left frame tube.

Lay the mirror on the ground, kneel down and get the flashlight pointed in the right place, and the numbers should be visible in the mirror.

Make sure the mirror is absolutely clean before returning it. Or you'll hear about it for weeks.

Location of belly numbers

belly2.jpg (113.1 KiB) Viewed 15724 times

[Simon]

If the covers are off the case halves, would casting dates also provide a worthwhile data point?

[hennesse]

Yes!

I'll keep everything in the database. As time goes on, we will start getting a clearer picture of everything!

Dave

[EKHKHK56]

But the patina ok I'll dig up casting tags. I thought about it LEFT side is easier to see if in motorcycle.

[hennesse]

Here are the first results for our call for VIN - Belly data. We've got a good start on the K-models.
Dave Carlton promises to send a bunch of Sportster data when he gets back from vacation.

If you're wondering what an "Uncoded Serial" is, the short explanation is that
we have to Un-do the odd/even serial numbering scheme used during the 1960s.

1953 looks kinda messy. But we can start to see a pattern emerging!

Keep those numbers coming!

Code: Select all

                             Un-coded
Serial           Belly         Serial   Belly       Diff
52 K 1121        552-1050        1121    1050        -71
52 K 1230        552-1205        1230    1205        -25
52 K 1679        552-1671        1679    1671         -8
52 K 1768        552-1830        1768    1830         62
53 K 1719        553-1322        1719    1322       -397
53 KK 2134       553-1704        2134    1704       -430
53 KK 2381       553-2477        2381    2477         96
53 KRM 2197      553-1697        2197    1697       -500
54 KH 1073       554-1044        1073    1044        -29
54 KH 1421       554-1444        1421    1444         23
54 KH 1937       554-2055        1937    2055        118
54 KH 2032       554-2168        2032    2168        136
54 KH 2189       554-1979        2189    1979       -210
55 KH 1121       554-2943        1121    2943   Prior Yr
55 KH 1139       555-1376        1139    1376        237
55 KHK 1802      555-1518        1802    1518       -284
56 KHK 1149      555-1989        1149    1989   Prior Yr
56 KHK 1170      556-1006        1170    1006       -164
56 KHK 2130      556-1962        2130    1962       -168
56 KHK 2137      556-2057        2137    2057        -80
59 XLH 1006      758-2441        1006    2441   Prior Yr
60 XLH 4562      760-2685        2562    2685        123
60 XLH 4838      760-2832        2838    2832         -6
61 XLH 1541      761-1712        1541    1712        171
62 XLCH 2373     761-3334        1373    3334   Prior Yr
65 XLCH 7119     765-4410        4119    4410        291


[dr dick]

Yes!

I'll keep everything in the database. As time goes on, we will start getting a clearer picture of everything!

Dave

exactly what my parole officer constantly reminds me.

[hennesse]

exactly what my parole officer constantly reminds me.

Remember back in high school when they told us "this will go on your 'permanent record' ?"

Dang, they were right. The NCIC remembers everything...

[thefrenchowl]

Pattern, what pattern??? ; O )



Patrick

[JohnBelcher]

Sorry it's taken me so long to get out to the shop to look at the belly # on the K. VIN- 53K 1749 - belly# 553-1621 John Belcher

[ThumpStreet]

Here's a couple of number sets for you Dave.Both have legit papers.1.)68XLCH4891 Belly# 768-9660 halves match,factory stamping 2.)69XLCH9771 Belly# 769-1276 case halves match although Dave C. noticed that the number stamping does not appear to have been done at the factory.His thinking is it was mostly likely a dealership replacement case as the casting grain shows no signs of being molested by an unscrupulous die grinder operator. I will venture to say that Dave C's theory is in line with my tear down inspection and the extensive parts replacement needed to bring it back into spec.I've got more persistence than sense.But it's mine now and I won't allow it to go to the tree row.Peter