overview - What kind of forks do I have?

if you're not too deep into the suspension theme, or even worse,

your bike has not stock forks, you may have some trouble to identify

your front shocks.

so how to determine which kind of forks do I have (Japanese brands)?


history of japanese MX-bikes equipped with Showa or Kayaba (KYB) forks:

1985 and older:

non cartridge forks

--> usually run 10wt oil, vary damping with oil wt.


'86 CR250 - first production cartridge fork. (today we call them "open bath cartridge"

or "single cartridge")

1987 and 1988 most other 125cc -500cc bike followed.

my knowledge isn`t that good about 80cc bikes, but I think some run non-cartridge forks till today. correct me, if I'm wrong

--> since that, every fork (except non-cartridge) until today runs 5wt oil as std.

the oil level is basically between 100mm and 140mm (except "bladder forks" - used on late KYB's. oil level there is 70-100mm)

on open bath cartridge forks rebound is on top!

how to change fork seals and oil:


again Honda started a new generation - closed cartridge (also called Twin chamber) forks

Suzuki also started with Twin chamber forks in 1997, but these forks were RSU (right side up)

KYB started their closed cartridge forks in 2005

it's almost impossible to measure the oil height, so the oil volume is specified

on closed cartridge forks compression is on top!

some bikes never changed to closed cartridge systems (KX125, Yamaha WR's)

how to change fork seals and oil:

now have a good ride, regardless of which fork you have :thumbsup:

Edited by kawamaha

very good write up!!

Great info!

ok, until 2010 you see the Showa Twin Chamber fork (left in the picture above) and the

KYB closed Cartridge fork (bottom) as stock forks in the bikes of the big four.

so in 2011 and later, new forks were introduced.

2011 and 2012 KX450F forks remains the same, but got blue anodized caps.

now have a look at SFF and PSF forks:


Actually 1994-1995 rm's had the first twin chambers USD forks. 45mm tubes

1996-1998 rm's had RSU twin chambers 49mm tubes

1999-2000 rm's had USD twin chambers 49mm tubes

2001-2003 rm 250's had kyb 46mm open chambers

2004 up rm 250's had 47mm twin chambers

2001 up rm 125's had 47mm twin chambers

Great write up though especially with the pics as I haven't had a 13' kx250f through the shop and didn't know the fork cap had changed!!

Actually 1994-1995 rm's had the first twin chambers USD forks. 45mm tubes

yes, meanwhile this info arrived at my home :D

I also have the hundreds of different suzuki forks in my database, but would be great to have some pics of these forks, too...

Great info!

Very good write up! Thanks!

PSF, SFF, TAC...what?
here are the 2015 forks:



all the 2014 KYB and Showa fork caps look like the 2013 caps

P.S. if you are looking for YZ forks, you are way too far down the page

Edited by kawamaha

What's with the different fork caps for the same air forks for different bike brands?

Some don't recommend pressure in the outer chamber eg honda 250 but Kawasaki and suzuki do

Good write up Kawahama

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