46mm kyb yz forks

potatoflake
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potatoflake
Edited Date/Time 12/28/2017 10:12am
I recently picked up an 01 yz250 and was just wondering if anyone has experience with making these forks work well for mx? I just got the correct rate springs and am wondering if I should go ahead and have them revalved while they’re apart?

205lbs C rider, mainly mx with occasional trail riding
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Acidreamer
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Acidreamer 12/9/2017 7:45am
12/9/2017 7:45am
Test them with the new springs for a few days and see where the forks fall. You cant revalve if you dont know what you want to improve.
potatoflake
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potatoflake 12/9/2017 8:08am
12/9/2017 8:08am Edited Date/Time 12/9/2017 8:08am
Good point lol I just see all these people swapping to the sss components and can’t help but think the 46mm cant be THAT bad

I took her out a few times for a shake down and it would blow right through the stroke but I’m hoping that’s just the 17 year old soft (stock) springs!
slipdog
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slipdog 12/9/2017 8:29am
12/9/2017 8:29am
Yes, very soft springs for your weight, but also at 17yrs old the cartridge seals are shot and don't hold the pressure in the cartridge. This will massively affect performance and they can't be fixed. The cartridge seal head is non rebuildable and the parts aren't available if you could rebuild it. Only option id new cartridges from Yamaha at a few hundred bucks a pop, if they even have them
potatoflake
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potatoflake 12/9/2017 9:27am
12/9/2017 9:27am
slipdog wrote:
Yes, very soft springs for your weight, but also at 17yrs old the cartridge seals are shot and don't hold the pressure in the cartridge. This...
Yes, very soft springs for your weight, but also at 17yrs old the cartridge seals are shot and don't hold the pressure in the cartridge. This will massively affect performance and they can't be fixed. The cartridge seal head is non rebuildable and the parts aren't available if you could rebuild it. Only option id new cartridges from Yamaha at a few hundred bucks a pop, if they even have them
Thanks for the Input, I don’t see a cartridge seal listed on the oem parts display for the forks so I guess I’m a little confused on exactly what part you’re referring to?

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slipdog
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slipdog 12/9/2017 11:41am
12/9/2017 11:41am
slipdog wrote:
Yes, very soft springs for your weight, but also at 17yrs old the cartridge seals are shot and don't hold the pressure in the cartridge. This...
Yes, very soft springs for your weight, but also at 17yrs old the cartridge seals are shot and don't hold the pressure in the cartridge. This will massively affect performance and they can't be fixed. The cartridge seal head is non rebuildable and the parts aren't available if you could rebuild it. Only option id new cartridges from Yamaha at a few hundred bucks a pop, if they even have them
potatoflake wrote:
Thanks for the Input, I don’t see a cartridge seal listed on the oem parts display for the forks so I guess I’m a little confused...
Thanks for the Input, I don’t see a cartridge seal listed on the oem parts display for the forks so I guess I’m a little confused on exactly what part you’re referring to?
Exactly... You can't get them. They're not available from a KYB supplier like Technical Touch either. The cartridge, like on newer "sss" forks has a seal and bushing that seals the cartridge rod as it goes in and out of the cartridge cylinder. Every set of those older open cartridges I see has as much oil leaking past the seal as goes out through the rebound valving the way they should.

That's not to say you won't be satisfied with the way they work if you spring them for your weight, but you can't fix the leaking seals. Personally, I consider them throw away forks.
potatoflake
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potatoflake 12/9/2017 12:13pm
12/9/2017 12:13pm
Thanks for shedding some light on these forks for me

if I’m not happy with the way they work I’ll be doing the swap to some forks That can actually be rebuilt
Jbulz
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Jbulz 12/9/2017 6:04pm
12/9/2017 6:04pm Edited Date/Time 12/9/2017 6:05pm
You can get seals for the cartridge head - I replaced mine about 2 years ago. Hygear suspension was able to order them for me, but I'm not sure where they got them.

I had Enzo do my suspension on my 03 YZ125 probably 10 years ago. To this day it is one of my favorite bikes to ride and I love the suspension on the thing. It always seems like it will be too soft, but I never have issues with bottoming. I like it more than my brother's 2011 YZ125 with SSS that Enzo set up.

Bruce372
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Bruce372 12/9/2017 6:32pm
12/9/2017 6:32pm
I have some brand new works parts to rebuild those cartridges
potatoflake
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potatoflake 12/9/2017 6:39pm
12/9/2017 6:39pm
Jbulz wrote:
You can get seals for the cartridge head - I replaced mine about 2 years ago. Hygear suspension was able to order them for me, but...
You can get seals for the cartridge head - I replaced mine about 2 years ago. Hygear suspension was able to order them for me, but I'm not sure where they got them.

I had Enzo do my suspension on my 03 YZ125 probably 10 years ago. To this day it is one of my favorite bikes to ride and I love the suspension on the thing. It always seems like it will be too soft, but I never have issues with bottoming. I like it more than my brother's 2011 YZ125 with SSS that Enzo set up.

Good to hear! I’m going to take a look at the cartridge tomorrow morning see if I can’t see anything that looks out of the ordinary, im really hoping these stiffer springs will be a big step in the right direction because I love everything else about the bike
potatoflake
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potatoflake 12/9/2017 6:42pm
12/9/2017 6:42pm
Bruce372 wrote:
I have some brand new works parts to rebuild those cartridges
works as in unobtainum? Woohoo
FGR01
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FGR01 12/9/2017 8:16pm
12/9/2017 8:16pm
Rode plenty of bikes with the 46mm KYB's back in the day that were made to be very good. They are also very simple to revalve yourself
slipdog
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slipdog 12/10/2017 5:47am
12/10/2017 5:47am
Jbulz- How did you put the seal head back together after removing the aluminium peening holding it all together?

Bruce- Who made those for you and since they look solid where does the seal go?
Bruce372
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Bruce372 12/10/2017 9:07am
12/10/2017 9:07am
slipdog wrote:
Jbulz- How did you put the seal head back together after removing the aluminium peening holding it all together? Bruce- Who made those for you and...
Jbulz- How did you put the seal head back together after removing the aluminium peening holding it all together?

Bruce- Who made those for you and since they look solid where does the seal go?
They use a pressed in bushing. Its a longtime ago, but from memory the original design was supposed to bleed off oil and these were made to stop that so valving changes were required from stock. I think Terry Hay sent me them
Jbulz
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Jbulz 12/10/2017 10:56am
12/10/2017 10:56am
My seal head was just a press fit bushing from what I remember. Once the damping rod is removed they just pushed out and were replaced pretty easily. It was a while ago, but I don't remember any peening aside from the peens on the threads to open the cartridge up.

My seal head looked pretty similar to the one that Bruce posted, but is definitely a production part.
potatoflake
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potatoflake 12/10/2017 11:00am
12/10/2017 11:00am
Bruce372 wrote:
They use a pressed in bushing. Its a longtime ago, but from memory the original design was supposed to bleed off oil and these were made...
They use a pressed in bushing. Its a longtime ago, but from memory the original design was supposed to bleed off oil and these were made to stop that so valving changes were required from stock. I think Terry Hay sent me them
Would you be willing to part with these for the right price or have an idea on where to score a set? If I’m going to have to replace the seals either now or in the future it would be awesome to have something like that!
potatoflake
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potatoflake 12/10/2017 11:11am
12/10/2017 11:11am
Jbulz wrote:
My seal head was just a press fit bushing from what I remember. Once the damping rod is removed they just pushed out and were replaced...
My seal head was just a press fit bushing from what I remember. Once the damping rod is removed they just pushed out and were replaced pretty easily. It was a while ago, but I don't remember any peening aside from the peens on the threads to open the cartridge up.

My seal head looked pretty similar to the one that Bruce posted, but is definitely a production part.
Music to my ears Laughing haven’t made it over to my fathers shop where the bikes at to take a close look at the cartridge yet but should be able to today. Thanks a lot to all of you guys for the info by the way, sounds like I have a set of seals to start looking for to keep handy Shocked
slipdog
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slipdog 12/11/2017 1:00pm
12/11/2017 1:00pm
The only ones I recall seeing like these here and the ones from an '02 250 I had in 2 weeks ago are designed like a shock seal head. Inside there's a bushing, seal than the steel washer held together by the end of the threads peened over the washer. If you grind that peend edge off to open it up, there's no way to hold all together. Weird...



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Bruce372
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Bruce372 12/22/2017 9:52am
12/22/2017 9:52am
Bruce372 wrote:
They use a pressed in bushing. Its a longtime ago, but from memory the original design was supposed to bleed off oil and these were made...
They use a pressed in bushing. Its a longtime ago, but from memory the original design was supposed to bleed off oil and these were made to stop that so valving changes were required from stock. I think Terry Hay sent me them
potatoflake wrote:
Would you be willing to part with these for the right price or have an idea on where to score a set? If I’m going to...
Would you be willing to part with these for the right price or have an idea on where to score a set? If I’m going to have to replace the seals either now or in the future it would be awesome to have something like that!
Let me know if you want these . Just need shipping covered

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