Shift Cover Rebuild Tips

[dcooke007]

Working on two shift covers for Doug Green and I know many questions come up concerning them. So I took some pictures and will offer my two cents worth to the group. Hopefully it will be helpful.

A logical process is required to assure good results and the first is to thoroughly clean shift cover and all associated parts, inspect for wear and replace all excessively worn parts. Next inspect the shifter shaft bore in the shifter cover and if worn machine the bore to accept bushings. In this case the cover was already machined for bushings. I usually start with the outer shift bushing and install flush with bushing drivers. On some shifter cases the fit of the shifter bore to the bushing is very tight and heating the shifter case moderately is required to install bushings. I was able to install these bushings with out heat and had a firm bushing fit when completed.

Install inner bushing and check bushing to shift shaft fit. One note...the groove for the snap ring on the shift shaft often has a ridge from the manufacturing process and should be removed with a small file before checking fit.

Next I modify and prep the shifter pin. This idea is not original to me, but I take it to the next level. I install the shifter pin in the shifter case to the proper depth and scribe the area the shifter arm rotates on. Then I drill the pin in the center and in the middle of the scribed lines. The pin is fairly hard and I use a carbide drill in my drill press for this operation. The size of the hole is not critical as long as it is not so large as to weaken the pin or to small to allow grease to flow. The hole I drilled is approximately .100 inch and I drill through both sides of the pin.

Using my Dremel tool and a heavy duty cut off wheel I grind a slot as close as possible in the center of the hole and to the end of both scribed lines. This is done on both sides of the pin and then lightly polish to remove any burrs. The pin has to be installed the same way it was when the lines were scribed ..so a notch is ground to indicate which end goes out. The idea here is to provide a path for the grease to flow along the length of the shaft to lubricate the pin, shifter arm bore and the shifter case / thrust washers. The supply of shifter covers seems to be running out and making them last as long as possible seems worth the effort. Although, makes little difference if you do not shoot a little grease in the lube fittings from time to time.

I will try to post more info tomorrow...getting late here.
Danny Cooke

[Zyx]

Danny,

Intense reading. Thanks for taking the time.

[dirtsquirt80]

nice work Danny

[DGardner]

Thanks for the great photos Danny....it helps a lot. DG

[dcooke007]

Doug's shift covers were bare so all new parts were purchased from Strictly Hodaka.
This is my version of a tool Doug demonstrated on the forum a month or so ago. It is useful to align the shifter arm / thrust washers and to check fit of shifter arm prior to final assembly. The shaft diameter is .392 inch and is approximately 2 3/4 inch long. The shaft end is ground to a point and the handle can be what ever length and diameter desired.

With the shifter arm installed I use a feeler gage to get a rough idea of side clearance. The shifter arm side clearance spec is .003 to .005 inch and .2mm / .008 inch and .3mm / .013 inch spacers are available for adjustment. I try to set the clearance as close to minimum with out the shifter arm binding when rotated on the pin.

A ridge was found inside this particular cover and was causing the shifter arm to bind when side clearance was set to minimum. Using my Dremel tool and Cratex rubberized abrasives the ridge was removed and the binding was corrected.

More to come later.
Danny Cooke

[dcooke007]

Using a heavy body grease to hold the spacer in place, I installed the correct spacer and aligned it with my home made tool.

At this point the shifter arm and spacer are installed in the cover and the cover installed on an engine to check for proper clearance between the sliding pin and the control shaft. The sliding pin should not apply side pressure to the control shaft.

This is an example of the kind of wear that can occur if side pressure exists between the sliding pin and control shaft. Excessive wear is also applied to the shifter arm bore, pin, side cover, etc.

With this side cover and shifter arm I did have a lot of side pressure on the control shaft. The shifter arm spacer was on the inside of the shifter arm so I could not get any more clearance by re-arranging the spacer. So I had to start looking for ways to find the required clearance.
The first thing I noticed was the sharp edges of the sliding pin were riding on the inside radius of the control shaft. I removed the shifter arm and filed a bevel on the long sides of the sliding pin. The pin is hard and I used a medium grit diamond lap to file the bevel. Careful use of a grinder, Dremel tool etc. would work also. A lot of clearance was not gained but I prefer not to have that type of point contact on moving parts.

To be continued.
Danny Cooke

[DGardner]

Again thanks for sharing this with us! DG

[dcooke007]

At this point I decided to grind .015 inch from the end of the sliding pin and re-cut the side bevels. Only a small amount can be removed. Still had more side pressure than desired.

Removed the sliding pin from the shifter arm and ground .015 inch from the face of the shifter arm the pin sits on and re-cut the chamfer.

Checked shifter arm operation and now no side pressure was applied to control shaft. But one other issue was noted when in first gear. The shifter arm was making contact with the slot in the shifter cover.

Rather than widening the slot I simply ground some material from the shifter arm.

Although a lot of work was required to fit this shifter arm and shift cover not all are this difficult. The object you are trying to accomplish is minimum side play for the shifter arm, no side pressure on the control shaft and no binding of the assembled components. Although this shifter cover only required one spacer others may not and may actually require one on each side or combination to accomplish desired fit.

To be continued.
Danny Cooke

[TimCC001]

Another great educational post, Danny. Your work is like the finishing touches and setting up of a guitar.

[thirdstone]

Hi Danny thanks so much for the informative post.
One question I have though is about the side pressure on the sliding pin. I would have thought that adjustment of the concentric bolt would have fixed the side pressure . What is different by doing what you did ?
Thanks , kev

[Bullfrog]

Kev:

Did you mean eccentric bolt? Rather than concentric bolt?

If so, the eccentric (adjuster) bolt in the shifter arm assembly has no effect on side pressure on the control shaft. The eccentric (adjuster) bolt adjusts the "at rest" position of the sliding key in the "in" or "out" (axial) direction of movement of the control shaft -thereby adjusting the "at rest" position of the control shaft (in each gear).

Ed

[dcooke007]

Hey Kev,
Like Ed stated, the eccentric adjustment does not affect side pressure applied to the control shaft. Perhaps if you think about the side load as a force applied by the shifter arm to the control shaft at a 90 degree angle would help. This is a photo from the Hodaka repair manual.

The foot change shaft and key has to be assembled and this is easily accomplished with a vise and brass vise inserts. It is important to get the pin started straight so extra care should be exercised at this point. The pin should be pressed in until there is a small amount of axial movement of the key on the pin and no binding when rotated. I usually install the circlip on the pin before pressing the parts together.

Next is adjusting the foot change shaft end play. The first picture is not quit accurate and is simply to show I do not install the ratchet spring when adjusting end play. I also do not install the ratchet plunger for this adjustment. Just makes it easier not fighting the ratchet spring or plunger. So install the foot change shaft with the ratchet and select the appropriate spacer or spacers. The Hodaka end play spec is .008 to .012 inch but I generally shoot for about .003 to .005 inch end play. In this example it required 4 spacers to bring the end play to desired spec.

At this point the foot change shaft and ratchet can be removed, the shifter case lubed, and the shifter fully assembled. Install shift lever and shift the mechanism through the gears.

Adjusting the shifter arm will be the next step.
Expecting to finish this up on the next post.
Danny Cooke

[rough rider]

As always Danny, excellent job! Very nice step by step information and clear photos. Thanks a million for sharing. Richard

[Forrest]

Nicely documented Danny. This needs to be archived for easy retrieval.

[dcooke007]

Ok for the last step you will need both hands. You can hold the shift lever in the vise with aluminum vise inserts and install the shifter cover on the lever. My vise inserts have a vertical groove cut into them to hold round stock. The shift lever extension sits in the vertical groove securely and holds everything still. You will notice the shift lever is installed in the opposite direction than normal. This allows me to work with out the shift lever contacting the freshly re-finished cover.

To perform the required measurements I use a depth micrometer, rubber bands and a flat piece of surface ground stock. The steel ground stock I use is .250 inch thick and 3 inches wide. Surface ground steel stock is very flat and consistent in thickness. You can use any size stock you want but I would not use anything thinner or less wide. Length only has to be long enough to reach across the shift cover flat surfaces. Measurement of the shifter mechanism is made with the shifter in third gear and at the center of the sliding pin. Distance specified for the shifter cover to the sliding pin is 1.380 inch and to quote the Hodaka manual, "measured at the center of shifter arm slack". Ok, so how do you measure shifter arm slack? Shifter in third gear with rubber bands installed as pictured, pull up on shifter arm to assure it is at the top of slack and measure distance as pictured and record measurement. A light touch is required so you do not over come the force of the rubber bands. Record measurement. Now remove the rubber bands and push down lightly on the shifter arm to assure it is at the bottom of slack. Measure and record. In this case the bottom measurement was 1.636 and the top measurement was 1.620 inch. 1.636-1.620 =.016 inch slack. With this information we can now measure and adjust the shifter mechanism. Flat ground stock thickness must be added to spec distance, 1.380+.250 =1.630. To account for shifter arm slack of .016 inch divide by two =.008 inch. So, 1.380+.250+.008=1.638 inch. Adjust the shifter arm at the bottom of the slack to 1.638 inch and that will account for the shifter slack and flat ground stock. The eccentric blot is rotated to move the lever up or down and then tightened to lock in place. It will take you a couple of tries to make the adjustment and to expect that you can get it to the exact thousandth of an inch is not likely. With in approximately .005 inch should be close enough. I have used the measurement method with good results.

I hope I have not complicated things too much. For me, it is more difficult to write this than perform the work.
Danny Cooke

[thirdstone]

Great stuff Danny, hopefully this post can be pinned so it does`nt get lost.

[DGardner]

I got my cover back from Danny and it is a work of art!!!!! The gun coat silver cover is very close to the OEM silver color. Thanks Danny for all your help. DG