have an oldsportster engine laying around in my pile i can't identify. the only markings i see on the outside are on the case right below cylinder deck on the primary side. it's 6 digits with a space between the first three digits and the last three digits. it has right hand shift so its 75 or older. any help, info or guidance is appreciated. thanks.

 

Up through '69 the first two digits were the year number. 1970 through '80 should be a number, letter, production numbers, letter, number. First two (number, letter) are model designation. Last two (letter, number) are year designation.

 

From your description it sounds like your engine may be 1969 or older. In 1970 the engines numbers started to be stamped on the right side case. Before that, the numbers (different format) were stamped on the left.
If you have a magneto or circuit breaker sticking up on top of the rightside timing cover it is for certain 1969 or older......pg

 

i appreciate the replies so far, but there are no letters in the markings i see. according to what pococj suggests, this would be a 1942 engine, which it is not. could it possibly be some aftermarket case i'm looking at? and yes, it does have a magneto sticking up on the right side. also has a hilborn pg150a pump mounted on the right side. looks like someone wanted to race this engine. any more ideas?

 

The numbers may have been stamped by someone other than the factory.
If you have a magneto, it should be a Fairbanks-Morse brand. If it is a Joe Hunt then it is an aftermarket mag. Both are rare and both are good though, so hang onto it.

Assuming that you have a mag rather than a circuit breaker, that leads me to believe you have an XLCH. Look at your primary cover. Is it cast aluminum or is it stamped tin?
Aluminum will indicate an XLH and stamped tin will tell you that the bike is a CH.

Back then there were 2 basic Sportsters.....the XLH and the XLCH. The XLH was the road version and the XLCH was the sportier (no pun intended) model.

Major differences in the very early sixties were......
Primary cover
Headlight
Gas tank
Wheels (XLH had 18 inch wheels on both ends) (XLCH had 4.00-18 rear and 3.25-19 front)
XLCH was kick start only with a center mount oil tank....either no battery or small left side mount battery.
XLH had kick and electric start with side mount oil tank.....large center mount battery

Those are the main differences between the 2 models way back when. As the bike becomes newer, the differences between the two become less and less.
By 1980 Harley had for all practical purposes combined the 2 models into one. The CH was always the most popular model however and the 'Legend' of the Sportster emanates from the CH.
Hope this helps you some.......pg

 

maybe you could elaborate on the different primary covers of the early sportsters. the primary on this engine in question is just the oblong oval without any protrusions in shape such as would be used in later sporties with a starter. the only cover i could find in my collection that fit is a cast aluminum one.
this brings up arelated question regarding another sportster engine i have (completely dissassembled) that is stamped as a 61 xlch, it has the protrusion on the top of the fatter end that would be needed for a engine witha starter. if that one is indeed a '61, why would the primary be that shape? a little more info on the different primary covers and their shapes may help me. thanks.

 

Your 61 is a restamp, protusion for lecky starter started only on the 67 XLH. XLCH got these lecly cases in 1970, with a blanking plate...

Your other engine is a pre 1969... If it's got a fuel pump, must be an old drag racer bottom end. Check the belly numbers. They should be the same on both halves, 3 digits to start with then dot then 4 more digits:

123-4567

1 is model, 7 for Sportsters
23 is the year they were machined, so anything between 57 and 69
4567 is a serial, starting at 1001

So 765-2452would bea 65 Sporty, 1452th set of cases machined that year

Patrick

 

info from patrick helped alot, but leaves me with more questions.

checked belly on both engines and the unknown one i originally asked about is stamped 761-xxxx, so looks to be a '61, but isn't stamped on both halves.

the engiine i show stamped as a 61xlch right below the cylinder deck also has numbers on the belly. both halves match, but they have two sets of numbers. one stamp shows769-xxxx, but that designation has a line stamped thru it. the other number shows 770-xxxx and is not lined thru. so, that case is origiinallya 69 that was restampedto a 70,and then stamped again as a '61 below the cylinder deck.
what i want to know now is: was this a motor company or a dealerrestamp? if i want to restore the '61 bike, which engine would i want to use. the true '61 that i have no title on, or the 69/70 restamped as a '61 which has a title? i figure the true '61 would be better.
any ideas and/or suggestions?
-thanks

 

Hi again, Moblue

Your belly 69 barred then restamped 70 is a set of factory replacement cases, so originally was a 61 which exploded its cases sometimes in 70. My 58 is exactly the same by some hazard, 769 barred then 770 butmy cases haven't got the hump... The VIN 61 XLCH was restamped when the dealer filled the right paperwork to obtain the new cases in 70. Nobody in judging circles would check belly #IMO, anyway, they are part of the bike history, use them, no problems there... even better, you've got a title for it so enjoy it!!! If you want to bring the cases more like they were in 61, I've seen people getting rid of the hump, no big deal if you know a good alloy welder...

The dealers couldn't obtain non numbered cases from H-D, they had to submit a legal form where they stated the original cases were dead, and tell H-D the serial, signed in triplicate or whatever... Then H-D would supply them with whatever cases they had on the shelves, stamped with the original VIN on the left pad.

Patrick