D2 Mistery Tag

[OldCat22]

I purchased a 5j D2 about a year ago. It had been sitting for over 10 years before i got it. It only shows 100 hours and i know the hour meter is working since i have put 5 hours on it so far. It runs excellent. The pony always fires on the first pull and the big engine runs great with good power and no blue smoke. Could this tag on the pony full tank be some kind of rebuild tag from the Cat dealer? It seems to have numbers that could be engine part sizes. There is some black lettering under the yellow paint but i can't make it out. I may trysome paint remover but i would hate to remove the black lettering also. Anyone have any thouts about what this tag is? I know this machine has more than 100 hours since it has Berco undercarriage.

[Old Magnet]

Does sort of look like a rebuilders tag......I wonder if it is a 3-3/4 bore engine converted to 4.00 in. bore.

[rjh-md]

If it is converted to 4 inch bore that means it has a Surplus tractor Parts Inc. increased bore liner kit in it ,same as my 5j ,and no available parts !

[OldCat22]

Thanks everyone for the responses. This is starting to make sense then. I wonder what kind of HP increase you can get from the 4.0" bore. It seems to have good power. It has a cat 2S blade but I haven't really loaded it too much. I'll see if I can take the top layer of yellow paint off an see if ther are anymore details on the tag.

[Old Magnet]

Close as I could compare in the rack setting manual is the 3J/5J is 32hp at full load rpm of 1525 and a 0.460 in. rack setting.
Compared to the 4U/5U at 47hp, same rack setting but 1600 full load rpm.