using a 1/2″ die from an Irwin 24 piece metric tap & die set.
How to remove rear wheel sprocket cush bushings on a Yamaha RD. Using simple tools you can see how much easier this process is instead of using a Dremel to cut them out.
Tools Needed:
Tap: 1/2″x13nc
Ratchet & 3/4″ socket
All-thread 1/2″x13x6″ double nut on one end, or 1/2′x13x6″ Grade 8 Bolt (Better)
Threading Oil
WD40
Propane torch
Notes on what I found in the process:
After removing all 4 bushings, the hub temperature was less than 150 degrees fahrenheit, as measured in the last bushing well closest to the bearings and seals.
After removing the 3rd bushing the threads on the all-thread were so rounded that it wouldn’t extract the 4th bushing. I cut off about 3″s of damaged thread, and was then able to extract the last one. Long story short…. use a higher grade material!
Thanks for watching,
Jim
UPDATE: 02/08/14
Finally got around to installing the new sprocket cush bushings in my RD400 hub. It was real easy and I used the same procedure to install the new wheel bearings. I sourced a Single Burner Electric Hot Plate from Target for about $12.00. I placed the hub on the hot plate and used the thermometer in my video to monitor how hot the hub got. I also placed the new cush bushing and wheel bearing in the freezer. Once the hub got up to about 130 degrees, I dropped the frozen cush bushings into the holes. They went right in without any force required. I did use a socket and tap on them to make sure they were fully seated, which they were. Did the same process for the wheel bearings, and the fell right in. Tapped on them also to make sure they were fully seated, which they were.
Note: When I installed the wheel bearings, I heated the hub up on one side facing the hot plate, removed from hot plate and installed that bearing. I them turned the hub over and placed it back on the hot plate to warm the other side, removed from the hot plate and installed the other bearing. Just make sure there are no burrs on the top edge of the cush bushing holes or wheel bearing holes. They should have a slight chamfer on the top facing edge to facilitate a smooth install.
UPDATE: 10/28/14
To prevent the first bearing from falling out when you flip the hub over to install the second bearing, place a large diameter socket on your workbench, which will be a spacer between the first bearing and the bench. This will keep the first bearing seated while you install the second bearing. Also, I found that I only needed to set my hotplate on low to get the required expansion.
Jim