Thanks to TCSTD, there's a great thread here on adjusting "adjustable" pushrods (https://www.hdforums.com/m_95088/tm.htm). A previous owner installed adjustables in my bike and I've installed new heads so I need to re-adjust. I can't tell what brand / model they are, so I can't use the typical "adjust to zero lash plush n number of turns" method. I've used the aformentioned thread to determing the following, and I'm hoping someone out there can give me a sanity check: With the engine stone-cold and the front cylinder at TDC on the compression stroke, adjust both front pushrods to zero lash plus 0.11". Does this sound about right? On my pushrods, that comes out to 1 flat (or 1/6th) less than 3 turns on my adjustable end.

Thanks!

Chuck

98 Big Twin Evo.

 

Pushrod adjustment procedure for the following tappet brands:

Revolution Performance Hydro-Rev (All)
Jims Powerglide
Comp Cams Hydraulics (All)
S&S Hydraulics (All)
Crane Hydraulics (All)

The whole idea in adjusting pushrods is to set the tappet plunger in approximately the middle of its range. Most lifters range is .200” from top to bottom so approximately .100” of depression is ideal.

1. Start by rotating the engine over until the front two cams are on their base circles (be careful the engine is not in the overlap cycle).

2. You have to make sure that the pushrod adjusters are exposed at all times. An easy way to accomplish this is to bend a paper clip into a hook on one end and connect
a rubber band to the other end. Stretch the rubber band up and connect it somewhere in the rocker box area. You can even do this to all four tubes before you start.

3. With the lifters on the base circle and the pushrods installed, extend the pushrod until zero lash is achieved. This means that there is no up or down movement but the lifter plunger is not depressed.

4. Make sure that the jam nut is loose and mark the pushrod with a marker so that you easily see when a full revolution has been accomplished.

5. At this point refer to the manufacturers specs for threads per inch and use this as a reference. Insert a decimal between the threads per inch number and that is how many full revolutions or turns that the pushrod needs (i.e. 32 tpi = 3.2 full turns).

6. You absolutely need to make sure that the lifters are bled down before rotating the engine over or valve damage can occur. This process can take anywhere from 5 to 15 minutes. You should be able to rotate the pushrods with your fingertips and feel a slight drag on them.

7. Repeat this process on the rear cylinder and replace the clips. Our pushrod tube clip installer makes this process a snap.

Pushrod adjustment for Jims Hydrosolid Tappets:

The Jims Hydrosolid Tappet is unique in its design in that it has approximately half the amount of plunger travel than most lifters. This design characteristic means that you must take the normal adjustment specs (32 tpi = 3.2 full turns) and reduce them by half. For example, if you would normally adjust the pushrod out 3.2 full turns you would now only extend it 1.5 turns or run the risk of holding the valve open. Other than this unique feature the process for adjustment is identical to a standard lifter.

 

RudeDog, thanks for the detailed reply... I'm sure it'll come in handy for others, too. I set mine to .10" past zero lash.

 

Actually I found that doing a Google search. It explains very well how I did mine, except I used clothes pins instead of wire and rubber bands.