Information Shock bottom out bumper

Joined
Apr 13, 2023
Messages
74
Reaction score
47
Points
18
Location
space
Visit site
I have a 2006 FZ6. One day while cleaning and lubing my chain, I had noticed that the rear shock absorber's bottom out bumper was disintegrating. The shock itself was fine with no leaks or excessive bounce or even bottoming out unless I had excessive weight for the preload.
Yamaha does not sell the factory shock absorber anymore. There are some available as new old stock, averaging around $150, and there are some used available , averaging around $80. They never sold the shock as individual pieces, so you could not get just the bumper, or spring, etc. Buying anything used and just as aged would probably get me a bumper that is also going to disintegrate in short time. If I were so inclined, I could buy any number of aftermarket shocks and install one. Yet bumpers cost about $20.
Nobody could say if the bumper cold be removed at the bottom side without disassembling the whole cylinder. This would lead to an entire rebuild. I do not know if I can even get the parts to do that. I saw that it looked like two different pieces of metal, chrome and aluminum, and decided it had to.
The first trick I had to overcome was getting the shock off of the bike after 17 years, as the lower bushing was very unwilling to move. After initially trying heat to no avail, then attempting a few other things over 3 hours with no results, finally finding someone else's report on the same issue here with everyone saying heat while I had a cup of coffee, I went back at it with my heat and it moved. Never underestimate the power of coffee.
Now I had the shock off. After removing the spring, I originally placed the bottom bushing in a vice and tried to twist the shaft with vice grips. (I used a cut piece of thick plastic tubing to give them grip while protecting the rod and gripped way down low where the bumper would cover so the cylinder should never touch any imperfections that may have been caused.) This did not work despite PB blast, WD-40, and heat.
I eventually flipped it around with the top bushing in the vice, upside down, used the vice grips in the same fashion to hold the rod, but put a pin through the bottom bushing to turn the aluminum piece and behold, it came apart!
IMG_20230404_155925882.jpg
You can see the original bumper in the center of the pic and its condition.
You can also see that there appears to be some kind of thread locker on the threads of the rod too.
I had bought an aftermarket bumper from a LAPS for $25. They had to order it of course. I had it 2 days later. It was probably for a dirt bike, but the dimensions were close enough. I cut the height down to the size of the one I was replacing, put it all back together, and have been riding fine since.
One day when I remember to, I will get a pic with the new piece on to post.
I will probably also as others had mentioned on the thread I saw about the bottom bushing, drill and tap a grease fitting into the bushing mounts, or at least take them out and re-grease them when I do adjust or change my chain, tires, or brakes. That was an extraordinary amount of effort over three hours to disassemble for no reason, that should have took 30 minutes.
Pics of the replaced bumper on the reinstalled shock.
IMG_20230501_185249875.jpg

IMG_20230501_185239190.jpg
 
Last edited:
Top