Hello,
Can anyone tell me how to tell 1000 Sportster cylinders and heads apart? I have heard that '72 to early '73 are different from late '73 to early '85. Is that correct? Specifically how are they different? Does anyone know the dimensions of the bolt patterns, casting numbers, etc.? One thing I noticed from looking at pictures of cylinders is that the head bolt holes on some are threaded all the way to the gasket surface and on others the threads don't start till about 1/2" down. Can you take pre '72 883 cylinders and bore them out to use 1000 pistons and use them on '72 to early '73 cases? on late '73 to early '85 cases? Thanks for any help.

 

The one reliable way to distinguish is to have a set of gaskets for each type and see which fits. This is the best that i have heard of in the past few years.

 

The head bolt pattern is different on all three heads 900, early 1000 and later 1000. You would not be able to use early jugs with later heads. The early 1000 cylinders were a lot thiner than later and you could only bore them out to about 30 over. As suggested earlier buy one of each head gaskets and use them as a guage to determine what cylinder head you have.

 

If I remenber correct this has been topic before... As wroted above...
72 cylinder will not fit into 73 crankcase (bolt pattern and diameter) but cylinder head should fit. 72 cyls made boring 900->1000 ??? but different bolt pattern in cyl head ??? thinner material than 73->

Cylinders 900cc ->71
Cylinders 1000cc 72
Cylinders 1000cc 73->

Cylinderheads front #16673-73, rear #16674-73

Compaire caskets ..

 

All ironhead heads have a counterbore on the bottom side of them that fits over the top of the liner that extends out past the surface of the cylinder (jug). This is what keeps the head lined up and keeps it from moving around, just like using a dowel pin.
On the late 1000 cc engines from late 1973 thru 1985 this counterbore in the head measures approx. 3.400" with a dial indicator or micrometer. On the 1st 1000 cc engines, Late 1972 and early 1973 engines, this measurement is a little less than 3.370, and on the 900 cc engines this measurement is somewhere around 3.250.
You cannot cut the counterbore on the 900 cc heads to make them fit on the later engines because the oil hole in the head surface is much bigger than the later 1000 cc engines and is too close to the counterbore to except the cut.
These cylinders will also NOT interchange on the crankcases for the same reasons.