See also Removing the Rocker Boxes in the Sportsterpedia.

Pull the tops and look for little marks on the inside. ¹⁾
There shouldn't be any outside of factory casting marks.
Rocker or pushrod contact will appear as marks that shouldn't be there.
If any are found, a little strategically located grinding cleans it right up.

Occasionally, 536 cams can cause the rocker arms to hit the rocker box tops (on the pushrod side).
This is rare, but it can happen.

Contact here should cause any damage, but it'll cause noise and leaks. ²⁾
A lot of rocker box top leaks have been traced to this.

Rocker box top damage 3)

Check for clearance issues between the valve spring / collar and the rocker box. ⁴⁾

When running big springs and cams, the additional lift can run the springs into the inside edge of the rocker.
In that case, the rockers should be clearance for the bigger springs.

This is more than just a nuisance noise. It will cause valve seat recession.
This means pulling the heads and changing seats, an expensive proposition.

That's one of the nice things about the 7mm valves with beehive springs in the late heads, it eliminates this problem.

Lower rocker damage from valve spring impact 5)

Valve spring clearance is a very common issue with high performance straight wound springs. ⁶⁾
Back before we went to beehive springs, this was a major headache for us.
People would lose valve seal and swear up and down they clearanced their rocker boxes adequately.
But later on, we'd get their rocker boxes and find spring/retainer gouge marks in them.
No matter what we did, we just couldn't get people to take it seriously.
If those springs hit the insides of the rocker boxes, you WILL get recessed valve seats, not maybe.
This issue went away when we migrated to beehives, thankfully.
It was a major motivating factor behind finding beehives that would work.
But they're not really suitable for all applications in HD motors.
Of course, now we're moving beyond beehives to the next great thing.

What you're looking for is to make sure the spring cannot contact the side of the box.
The clearancing can be done with a drum sander on a dremel type rotary tool ⁷⁾ or a die grinder.

Big springs can cause this issue. 8)	The clearancing job doesn't have to be pretty. You're just creating space for the springs to miss the rocker. 9)

Before clearancing. 10)	Top view 11)

After clearancing. 12)	Top view 13)

The rocker arm shaft is not supposed to rotate from it's installed position.
It has a notch in one end that goes around a bolt used to install the lower rocker box to the head.

What moves is the rocker arm itself.
The bushings in the rocker arm pivot around the rocker arm shaft.
The shaft runs through bushings on both ends of the rocker arm.
These bushings can expand due to normal wear.

The FSM suggests visual inspection and measuring of specific clearances as outlined below as a guide to when to replace parts.
Ultimately, it's an individual judgment call as to replacing parts that are within measured specs.

Service wear limits are a guideline for measuring parts that are not new.
Replace parts when their measurements exceed the wear limits below.
If wear limits are not given for a part, refer to the new install specs. ¹⁴⁾

The ends of the rocker arms can wear down the area where they touch the lower rocker box.

• Push the rocker arm to one end.
• Check the clearance between the other end and the cover with a feeler gauge.
• The FSM suggests to replace the rocker arm or lower cover or both if the end play exceeds .025” (.63 mm). ¹⁵⁾
  

Checking end play 16)

If the rocker arm shafts will not slide out on their own;
You can remove them by tapping them out using a hammer and a soft metal punch. ¹⁷⁾

You'll be measuring for an 'out of round' condition of the rocker arm and associated parts.
Most of the wear in the rocker arm shafts and bores results from up and down movement of the pushrods and valves. ¹⁸⁾
This can result in an out of round condition on either or all of these parts.
(more wear in the top and bottom than the sides)

When measuring the rocker arm shaft end, it's bushing or cover bore,
Take a measurement and then turn 180° and take another measurement.
The two measurements should be the same in newly installed parts.
Subsequent wear will happen from top to bottom and need replacement.
This could induce noise and expedite wear on the parts.

All measurements should be taken from the top to bottom position as each part sits while installed as per the FSM.
That is where most of the wear will be as mentioned above.

1. Measure and record the rocker arm shaft dia. at each bushing area with a caliper.
2. Measure and record the I.D of the rocker arm bushing with a telescoping bore gauge and caliper.
3. Subtract the shaft dia. from the bushing I.D. and match that number against the wear limit specs.
   • If the bushing is at or past the service wear limit, proceed to “replacing the bushings” as in below.

Same as checking bushing clearance; All measurements should be taken from the top to bottom position as each part sits while installed as per the FSM.
That is where most of the wear will be as mentioned above.

1. Measure and record the dia. of the rocker arm shaft at each rocker bore with a caliper.
2. Measure and record the I.D of the rocker box bore for the shaft with a telescoping bore gauge and caliper.
3. Subtract the shaft dia. from the rocker box bore and match that number against the wear limit specs.
   • If the either are at or past the service wear limit,
     • Check the dia. in the middle of the shaft against the dia. at the end. Both places should be the same.
       If the shaft is smaller in dia. on the end, replace the shaft and recheck the measurements.
       (this is cheaper than replacing the lower rocker cover)
     • If the shaft mic's out OK, then replace the lower rocker cover.

The exhaust side rocker arms have one tiny little hole that the intake rockers don't have. ¹⁹⁾
This tiny little hole is for extra oiling for cooling exhaust side.

While you have the rocker arms out,
You can use a welding tip cleaner or other small wire to poke down this hole to clean or verify the hole is clear.

^{20) 21)}

• Look at the condition of the valve stems in the heads.
  This will give you an indication of how the rocker pad is wearing against the valves.
  Check for pitting or uneven wear.

• Inspect both the rocker arm pad and pushrod end for uneven wear or pitting.
  Replace the rocker arm if either exist.

Replace the rocker arm bushings one at a time.

1. Press or drive the bushing out of the rocker arm.
   • If the bushing is difficult to remove, thread a 9/16“x18 tap into the bushing.
     Then, from the opposite end, press or gently knock the bushing / tap out of the rocker arm.
2. Press the replacement bushing into the rocker arm flush with the arm end.
   • Place the split portion of the bushing towards the top of the arm.
3. Line ream the bushing using rocker arm bushing reamer (94804-57).
   • “Jims” also makes this tool. You can find it online.
   • Use the remaining old bushing as a pilot hole (to keep center).
4. Once you've got the new bushing reamed, repeat the procedure for the bushing on the other end.
   • This time, you'll use the new (reamed) bushing as a pilot hole to ream the second bushing.

“Jims” makes this reamer for the rocker arm bushings. It is referenced to HD part number (94804-57) 22)