* . . . Installation of the Top End

The chart below, with head part numbers, is a compilation of parts catalogs and shows when the changes occurred and to which year models the changes affected. ^{1) 2) 3) 4) 5) 6) 7)
8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28)}

4 steps to head identification just from site plus head bolt spacing: ²⁹⁾

1a. If these fins are present, your looking at 900 heads for sure. In later 71 these fins disappeared. That means:30)	1b. There are some 900 heads that didnt have those fins and no 1000 heads have these fins. If no fins go to step 2.31)	2a. Decide if the heads are later 71 (900) or 1000. Do that by looking at oil drain size Note the size of drain compared to head bolt holes.32)
1957-71 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.440“. 57-mid 73,threads for head bolts, come all the way up to the head gasket surface on the cylinders.33)
2b. 1000 uses 3/16” oil drains. Now you know if your looking at late 1971 900 (big drains) or 1000 (small drains). If heads have small drains go to step 3 to determine if heads are E1000 (72-E73) or L1000 (L73-78). 34) When the change to 1000 happened in 72 the cylinders casting size was increased but for augments sake the head casting was not. Consider the cylinders: The bore was opened .094“ radius. That pushed to the oil holes in cylinder to a larger pattern. To get the matching larger pattern in the old heads, the holes needed to be reduced in size so they still fit in the 900 size casting.35)	3a. E1000 (72-E73) On 900 heads (smallest bolt circle), the bolt holes bulls-eye the casting boss. Looking close at the 72 heads you can see the bolt circle was slightly enlarged while the casting boss stayed at the original position. 36)	3b. L1000 (L73-78). In later 73 the 1000 heads change to bigger bolt pattern.37) The L73+ heads have the spot facing further out on the casting boss. In other words, the PCD of the spot facing is greater than on the 72/e73 heads. 38) In L73 the bolt circle was really enlarged. Again the boss stayed at the 900 position. There is added meat around the bolt holes between the fins but that's a moot point in identifying what year heads your gawking at. 39)
	72-mid 73 1000 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.540”.40)	L73 - 85 bolt pattern ( inside of hole to inside of hole, diagonally ) is 3.640“. Late 73-85 threads for head bolts are recessed in the cylinders by 1/2''41)
4. In 79 a boss was added for a/c mounting. This is a 79 only head. 1980-1983 is same as 1979 but doesn't have the intake o-ring lip. 84-85 had no intake o-ring lip either. The air cleaner boss was still present but it wasn't drilled or tapped.42)	84-85 heads also had the shoulder-less valve guides and took a small washer for the inner valve spring instead of the full size lower spring collar the previous heads used. The valve guides do require machining if you want to use a seal the top spring collar will contact them. 43) While this info is accurate, don't let missing guides or incorrect vintage guide installation influence you in identifying what heads you are looking at. 44)

* . . . Three angle valve seats - 1980 and up FLT/FL/FX/XL models

* . . . 1983 valve guide changes

The chart below, with valve component part numbers, is a compilation of parts catalogs and shows when the changes occurred and to which year models the changes affected. ^{46) 47) 48) 49) 50) 51) 52)
53) 54) 55) 56) 57) 58) 59) 60) 61) 62) 63) 64) 65) 66) 67) 68) 69) 70) 71) 72) 73)}

• From a Service Bulletin in October of 1981, all standard sized pistons are graded for size in .00025” increments. This is done for production purposes on­ly and does not apply to oversized (.010“-.070”) pistons. ⁸⁵⁾
• The grade number is stamped on the dome of all standard pistons. In the case of a grade 10 piston, the number 10 is stamped on the dome. This is a standard sized piston and should not be confused with a .010“ oversized piston which also has a number 10 stamped on the dome. If there is any doubt about a piston's size, it's largest diameter should be measured.
• In the future, all grade 10 standard pistons will be marked “G10” for ease of identification. All oversized pistons used in oversized cylinder bores (.010”-.070“) will continue to be stamped in the usual manner.
• Example:
  • Standard Grade 10 piston range: 3.18725”-3.18700“ stamped with “10” or the new G10 stamping (old style).
  • Oversized .010” piston range: 3.197“-3.196”

When checking for the up and down play, it helps to spray the crank pin area down with brake cleaner. ⁸⁶⁾
This is to rinse down any oil that may be clinging to the roller bearings.
The oil can take up space between the rollers and not give an accurate feel.

However, don't forget to oil it back up before re-assembly. ⁸⁷⁾
You don't want raw metal rubbing each other on start up.

Side shake measurement (76 and earlier models) can be done with a ruler using the outside edge of the case as a base line.

Check rods for (up and down) play as well as (upper end side shake or rod tip) with the pistons removed from the rods. ⁸⁸⁾
When appreciable up and down play is found and side shake at the extreme upper end of the rod is more than the following specs;
The lower bearing should be re-fitted.
Specs:
Front: 3/32“ or more
Rear: 3/32” or more

Check rods for (up and down) play as well as (upper end side shake or rod tip) with the pistons removed from the rods. ⁸⁹⁾
When appreciable up and down play is found and side shake at the extreme upper end of the rod is more than the following specs;
The lower bearing should be re-fitted.
Specs:
Front: 11/64“ or more
Rear: 3/32” or more

Motorcycles using rod bearings with steel retainers:
Check rods for (up and down) play as well as (upper end side shake or rod tip) with the pistons removed from the rods.
When appreciable up and down play is found and side shake at the extreme upper end of the rod is more than the following specs;
The lower bearing should be re-fitted.
Specs:
76 and earlier (from the 70-76 FSM): ⁹⁰⁾
Front: 11/64“ or more
Rear: 3/64” or more
76 and earlier (from the 70-78 FSM): ⁹¹⁾
Front: 3/64“ or more
Rear: 1/64” or more

Motorcycles using rod bearings with aluminum retainers:
Check rods for (up and down) play with the pistons removed from the rods. ⁹²⁾
Side shake cannot be used to determine bearing wear.
When appreciable up-and-down movement is found, the lower bearing should be refitted.

Check rods for up and down play in lower bearings. ⁹³⁾
Measuring side shake is no longer recommended in the FSM as in above.
When up and down play is detected, the lower bearing should be refitted.