jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Hello,

It's been a while since I posted anything but I have a strange problem with some Showa forks.
I'm not a novice at suspension service, but neither am I an expert so I feel that I know how to bleed the cartridge, but this doesn't seem to be a cartridge bleeding problem.
What is happening is similar to what folks describe as not having bled the cartridge prior to installing the compression assembly. But this isn't an air in the cartridge problem. After bleeding the ari out of the cartridge and I install the compression assembly then compress the cartridge rod a few inches (like 4), it should come immediately back to being fully extended, but instead it pukes out oil out of the two bleed holes out of the top of the cartridge assembly. Inspecting the rod shows not oil on it, therefore I feel that the lower cartridge seal is ok. If I continue to push on the rod, most of the oil from the internal chamber will be displaced out of the bleed holes.
I have had this happen to a number of forks with a reasonable amount of time on them, just recently mind you, and having replaced the lower cartridge seal did not fix this problem.
The only way of fixing this was to use another compression assembly from another bike. Then it worked like it should, only a small amount of oil being displaced once you install the compression assy (depends on how much you fill the cartridge of course). Once I did this the rod would return to it's full length when compressed.
So, my question, can you buy the seal in the compression assy that is inside the bushing assy or is the only fix buying a new entire compression assy?

I am wondering if the oil I am using may have caused this; maybe Amsoil Suspension fluid is bad for the seals in the cartridge? I ask this since that is all that i have used for two years and owning 7 bikes, I have seen this on at least two of them. I doubt that this is the case, but the bikes that I am working on are only a year old, and one has 70 hrs and another 2006 CRF450 has about 25. I have tried different oils to try to resolve this, once I notice that there is a pblm, but that did nothing ( I have tried 5wt through 20wth as an experiment).

Has anyone seen this problem or am I dong something wrong?

Any advice is appreciated!

Cheers!
 

blackjack

Member
Aug 11, 2002
55
0
If I'm reading you correctly you are saying that the twin chamber rod does not extend fully after you have reassembled the cartridge and that the labyrinth seal at the bottom is leaking. I would try calling someone like Pro Circuit or Factory Connection to see if that seal would be available for replacement.
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
I did replace the bottom seal in the cartridge and this did help, but what I ran into was a bad seal in the compression assembly. The one behind/inside of the bushing.
You can order these from MX-TECH, they are 12x17mm.
The sympton was when installing the compression assy then stroking the dampening rod up and down into it's full movement, most of the oil would be displaced out of the bleed holes in the cartridge housing. This would cause air to enter and cause a vaccuum.
It would also cause the forks, when riding, to feel initially soft but becoming hard in the mid stroke due to an increased oil level in the outside chamber. The same sympton is experienced when the oil escapes past the lower cartridge rod seal. Changing both made the forks feel "like new".
I'm surprised that no one has run into the compresson assy seal failure.
In the past two weeks I'm run into 3 forks with this sympton.
Cheers!
 
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