Checking spacer measurement.jpg (71636 bytes) Installing shaft end spacer.jpg (76085 bytes)
Checking spacer measurement.
Installing shaft end spacer.
Installing rocker arm shaft.jpg (74769 bytes) Installing inner spacer.jpg (74603 bytes)
Installing rocker arm shaft.
Installing inner spacer.
Installing shaft and aligning set dimple.jpg (71313 bytes) Setting the rocker shaft.jpg (72375 bytes)
Installing shaft and aligning set dimple.
Setting the rocker shaft.

     One of the reasons for the procedure was because the V-twin camshaft was not centered in the engine. The angle of the front exhaust push rod leaves a lot to be desired. In early testing the pushrods with the 1/4-inch hardened adjusting screws would snap whenever they felt like it. This occurred not only on 4-valve engines but any V-twin that could twist up revs.

     The industry has responded to this with a new breed of pushrods with larger adjusting screws. I am presently testing the Taperlites  made by Rivera Engineering with good results.

     Now for the most overlooked part of this assembly and probably ninety percent of the problem of noise, the rocker arm end play. When the cam raises the pushrod and moves the rocker arm down on the valves, it also sends the rocker arm away from the pressure of the pushrod. When the push rod goes down and the springs push the valves shut, the rocker arm goes to the opposite side.

     There's your noise, but the fix is easy. The process to check is:

     First the rocker arms cannot have any pressure on them from the pushrod or the springs. They must be able to move back and forth freely. In most cases, they can be checked by removing the rocker cover and positioning the cam properly. If you have to remove the rocker boxes from the engine, do so. Push the rocker arm as far as you can one way or the other Place a feeler gauge between the stainless steel spacer and the rocker arm if the clearance is over .008 (eight thou­sandths). For future reference measure and record the end play of each rocker arm. You need to remove the rocker shaft and arm to remove the spacers.



     There is a set screw on the bottom side of the rocker box that holds the shaft in place. Remove the set screw with a 1/8-inch Allen wrench.

     Give some thought on how you want to do the following as the shaft is usually hard to remove It also must be pulled straight out and without damaging any of the other parts. I got frustrated at most of the systems I had available and designed my own rocker shaft pulling tool back in '91. You may want to try and make something similar.

     There is a 1/4 x 20 thread tapped in one end of the rocker shaft. This is used to pull the shaft out of the rocker box. Remove the shaft completely and lift the rocker arm and the two stainless steel spacers from the rocker box. The rocker arms are numbered for identification and though they may appear to be the same, they are not. You may even want to put your own markings on it so that you return it to its proper position.

     This is a good time to check the rocker shaft and bushings for wear. Of course, they should be replaced if worn. Parts are available, but bushings must be line honed If they are replaced.

     Measure your stainless steel spacers. If they are original, they should measure .032 (32 thousandths). Take the end play measurements you previously recorded, start with any shaft that you want to, subtract .004 (four thousandths) from that measurement, and then divide that measurement by two. The resulting number is what has to be added to that shaft's spacer.




Spacers are available 032/034/036' 38/40 

     Once you have figured out what set of spacers you need, place a light coat of grease on housing spacers, shaft, and rocker arm bushings Insert the shaft just enough to install one spacer. Then carefully place rocker arm into the rocker box and shaft into rocker arm. Turn rocker box on end with shaft end facing up. Carefully slide other spacer into position while holding rocker arm up. Push the rocker arm shaft in just enough to pass through washer and start into box. Do not go too far  (remember what a pain it was to get them out earlier. Check your measurements and if they are correct, proceed. If not, continue to change spacers until you get a perfect fit.


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