Hard Shifting And Oil Leaks - Ratchet Top Tune Up - Tech STC

With the ratchet top completely cleaned and the gasket surfaces stoned, we reassembled the detent using a liberal coating of white Lithium grease on the inside of the detent bolt, internal spring, and the detent itself. After the detent bolt was tightened we bent one of the locking tabs over one of the flats.

We then turned our attention to the shifter pawl mechanism. The shifter pawls (A) are spring-loaded in the pawl carrier (B) to hold constant tension against the shift gear shaft. The pawls also have a machined groove on the outside that rides on a pin pressed into the pawl carrier. This pin and groove arrangement keeps the pawls from rotating.

The top of the pawls have a slanted top and a machined shoulder. When the shift linkage is pulled or pushed, the pawl carrier rotates, allowing the edge of the pawl's shoulder to rise and engage one of the notches of the shift gear shaft. The continued rotation of the carrier rotates the drum, moving the shift forks to the next gear. Once this movement is complete, the carrier returns to the central position. Only one pawl works at a time; one pawl for upshifts, the other obviously for downshifts. While one pawl is pressing into the notch on the shift gear shaft, the other pawl is being pushed down into the pawl carrier out of the way of the shift gear shaft, springing back up once the movement is completed. A slightly sharp or crisp corner at the top of the pawl aids in engaging the shift gear shaft notch. Here we are touching up the top edges on a hard stone with some 3-in-1 oil.

The pawl carrier revolves on the end of the shift gear shaft separated by a bushing. Here we are checking the fit of the bushing on the end of the shift gear shaft. You want a nice slip fit here; a little wobble is OK.

The outer surface of the pawl carrier is stoned to remove any burrs or dings that could wear grooves in the aluminum cover.

The aluminum cover also receives the attention of the stone on the gasket surface. The inner surface (arrow) where the pawl carrier rides is smoothed as needed with a piece of emery paper.

The pawl carrier springs go in first into the sheet metal guides that have been coated with white Lithium grease. There will be a small gap at the top guides between the two springs where the tang on the carrier fits.

We have assembled the pawl carrier using the white grease complete with pawls and springs. To assemble the ratchet top we tilt the carrier down (A) slightly catch the pawls on the gear shaft and gently push forward (B) until the carrier bushing (C) aligns over the gear shaft, and then gently push down so the bushing seats on the shaft.

Rotate the carrier carefully in both directions, ensuring it moves freely and the pawls engage the shaft. When the pawl carrier moves freely and easily, slap a coat of white grease on the outer surface of the carrier, and new gasket and the carrier cover can be screwed on to the top. A small drop of blue Loctite on the screw threads is in order, but don't over-tighten the screws.

The last step to a smooth-shifting transmission is to align the top to the shifter forks. The easy way is to use a alignment tool as shown in the photo, but it can be done just using the top itself. The benefit of the tool is you can check both shift forks at the same time. Using the top you need to do one fork at a time. To use the tool we placed it on the top using the dowel pinholes. We then aligned one of the sliding guides (A) with the straight groove (B) of the left side of the shift drum using the tools alignment rod (C). When the rod rotated freely, we locked the guide with the thumb screw.

Here is where the tool comes in handy. To align the right side of the drum we needed to rotate it until the straight section of the groove presented itself as shown here, then, using the same rod, we locked the guide in place. Basically we have just set the tool to check both shifter forks in neutral; using the top by itself you would place the top on the case and check the alignment of one fork, then rotate the drum for the other fork.

OK, what we see here is that the 1-2 shifter clutch (A) is too close to first gear (B) on the left, with a large gap to second gear (C). We want the gap to be equal both sides, so we need to move the shifter fork over towards second gear.

To move the shifter fork over, it's a simple matter of adding some shims between the locking tab (A) and removing some shims from the right side of the fork (B). Most of the time you can just swap the shims from side to side to gain the spacing you need.

Here we have moved the shims (it took two tries to get it perfect) on the shifter fork, reinstalled the fork, and repositioned the tool and rechecked the alignment. This is the spacing we wanted. We also checked the three-four-shifter clutch on the main shaft. It didn't need any shimming, but if it did we would have used the same procedure to bring it to spec.

OK, that about wraps it up. We secured the shifter fork shaft in the case, coated everything with the white grease, placed the top in neutral (the same with the shifter forks), and carefully lowered the top on the case. The top should fit perfectly, no banging or beating is needed. If the top doesn't fit perfectly, pull it up and find out why. Most of the time we've found that one of the shifter forks has slid over to one side (white grease is slippery); reposition and try again. Once the top is in place, replace all the screws that you have already cleaned and tighten them down evenly.