Oil Pump Removal, Aftermarket Cover Install
The stock oil pump cover is very thin stamped piece of steel. It flexes under high rpm and allows leakage back to the sump which may reduce oil pressure in the engine. The stock oil pump cover can be seen gushing oil when the oil pump is turned with a drill with the clutch removed. Chances are it leaks a lot worse when the oil pump is turned by the engine. There are a few aftermarket oil pump covers designed to resolve this problem. All of the aftermarket covers are nearly identical in shape and material. A high volume oil pump gear and high psi relief valve are two additional aftermarket items that are designed to improve oil pressure. It seems these are not of much value without being able to increase the amount of available oil in the sump.

Related thread
Oil Pressure Enhancement

Do First:
Remove Clutch Cover
Remove Clutch Plates
Remove Clutch Hub and Basket

Tools:
clean sheet of plastic
5 mm allen key socket with 3” extension
Sharpie
aftermarket oil pump cover
molybdenum disulfide and oil
high temp grease
Torque wrench

Removal
1. Line the bottom of the engine case with a clean sheet of plastic to prevent any small parts from rolling down into the sump. Use a 5 mm allen key socket with 3” extension to remove the three screws that secure the oil pump cover to the inside of the engine case.

For reassembly, I used a Sharpie to mark the tooth on the gear that pointed straight up. Engaging the teeth of the oil pump drive gear to the gear on the clutch basket precisely as they had been installed is probably not crucial. You cannot see what teeth are meshing before the clutch basket is removed/installed anyway.

2. Use your fingers to pry the cover from it’s mount. Slowly pull the cover with the drive gear, shaft, washer and inner rotor out of the oil pump. The outer rotor will probably be pulled forward as well. Be careful not to drop these parts. The pin in the shaft directly behind the cover will almost definitely fall out as you withdraw the shaft. Plastic sheet is highly recommended.

Before the parts get misaligned, mark the inner rotor to the outer rotor with a Sharpie.

These are the parts that should be removed. The washer will stick in a recess on the back side of the cover.

The dowel pin marked by the blue arrow in the pic above will probably remain stuck in the engine case.

3. If necessary, you can pull the outer rotor straight out of the engine case.
Installation

4. Remove the washer from the OEM oil pump plate and place it in the recess in the aftermarket oil pump cover.

5. Apply a solution of molybdenum disulfide and oil to the journal portion of the gear shaft. Slide the cover with the washer over the gear shaft so it contacts the gear. Insert the pin through the hole in the gear shaft and slide the inner rotor onto the gear shaft. Align the pin to the slots in the inner rotor and push the inner rotor up the shaft so it contacts the cover. Hold the parts in this position so that the pin cannot fall out of the shaft.

6. If the outer rotor was removed, insert it to the engine case. Apply high temp grease to the dowel pin. Position the oil pump cover so that the bolt holes align to the bolt holes in the engine case. Insert the shaft through the outer rotor holding the inner rotor against the inside of the oil pump cover so that the pin cannot fall out of the shaft. You will need to twist the gear to align the tongue at the end of the shaft to the slot in the water pump gear it inserts to. Twist the oil pump cover to fit the dowel pin to the hole and press the cover against the engine case.

Thread in the three oil pump cover screws and draw them up evenly. Torque the screws using a 3 inch extension and a 5 mm allen key socket.

Torque - Oil Pump Cover Bolts: 9.8 N·m (1.0 kgf·m, 87 in·lb)

7. Remove the sheet of plastic from the bottom of the engine case.
Install the Clutch Hub and Basket
Install Clutch Plates
Install Clutch Cover

Weights
Replacing the OEM oil pump cover with an aftermarket cover results in a weight gain of 1.75 oz.

* Last updated by: Rook on 6/16/2018 @ 10:40 PM *

I did this today, and I want to reiterate what Rook says about putting a plastic sheet down. I managed to drop an allen socket in the oil pan before I put a trash bag down as a barrier. After I put the trash bag down, I still managed to drop the oil pump retainer pin and also one of the oil pump cover bolts. Fishing stuff out of the oil pan isn't impossible, but it's better to not have to do it.

Also, the clutch pressure plate is keyed. I somehow missed this, and I couldn't figure out why my clutch wasn't actuating properly. I took it apart 3 times trying to figure out what I did wrong, until I realized it was just the clutch pressure plate not being in its slot.

I don't remember the Gen1 pressure plate having any kind of key for exact positioning. I did mark the bolts to both the pressure plate and the boltholes in the hub so it all went back exactly the way it came out. The key for the pressure plate must be a Gen2 update. I'm glad this tutorial was of use to you on your Gen2 TXZX. Someday down the road, I'll be doing a Gen2 version. I understand there's quite a bit of change to the clutch on the Gen2. Thanks for the heads-up on the pressure plate key.