Kx500 forks trail?

Got questions? We got answers....
Post Reply
Frysk
Member
Posts: 132
Joined: 03:02 pm Dec 04 2011
Country:
Location: Droegeham (The Netherlands)

Kx500 forks trail?

Post by Frysk »

Hi everyone,

I recently installed a 1990 kx500 fork on my kdx200 but its to hard for trail ridin', so I need some tips to make it soak up the small stuff a bit better, I'm thinking of revalving but how ? I've never done something that and letting it do by a company is a bit to expensive for my taste.
I'm also thinking about playing with the oil level but how much goes in stock and how much would be best for trails ?

Any extra tips would be apreciated.
KarlP
Supporting Member III
Supporting Member III
Posts: 1484
Joined: 02:26 pm Jun 29 2005
Country:
Location: Alabama

Post by KarlP »

I'd look at a couple of things first.

You might try a 5 or 2.5 wt fork oil
make sure the lower pinch bolts are not too tight and that the forks are aligned
front tire pressure
Clicker adjustments. "Softer" is not really softer. It is less damping which may not be what you want.
Spring preload - not too much and not too little

I'd look over at some of the KX500 sites for what others have found.
'08 KTM200xc
'99 CR/KDX Hybrid with that RB stuff done to it
KX100 for the boy
Frysk
Member
Posts: 132
Joined: 03:02 pm Dec 04 2011
Country:
Location: Droegeham (The Netherlands)

Post by Frysk »

Thanks,

I've found that the oil level range is 70-120mm.. But I can't find how and where I'm suposed to measure that..

I asume thats on the top of the leg with the spring out, but compressed or extended?

Sorry for the so many questions :$ this is my fist inverted fork and the only thing i've done to conventional forks are replacing the seals and filling it up with factory specification amount of oil.
User avatar
kawagumby
Gold Member
Gold Member
Posts: 927
Joined: 10:09 am Nov 30 2006
Country:
Location: California

Post by kawagumby »

Take a look at what many folks have done to MX fork compression valve stacks in the USD section here. Basically, you will probably want to remove about half of the shims. Most guys only run 4 or so of the 24mm dia. Also make sure the spring rate isn't too stiff, depending on your weight/skill. The stock KX500 springs, as I recall, are 40's so they may be a bit harsh unless you are an aggressive rider or weigh more than 170 lbs.
The shims are held in place with a nut on an aluminum treaded rod. carefully file off the peened end before you remove the nut - when re-assembling make sure the threads are clean and use locktite. Don't over-tighten the aluminum threads!

A tip; to take the compression stacks out, pull off the gas tank, squeeze off the tranny vent hose with vise-grips, wrap some rags around the handlebar controls, flip the bike upside down....and spin those babies right out (modify one side at a time leaving the other in place) with an impact wrench. :partyman:

For oil level, most off-road USD's work better with less oil, I usually run 120mm to get full travel more easily - the measurement is taken with the forks completely compressed.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
Frysk
Member
Posts: 132
Joined: 03:02 pm Dec 04 2011
Country:
Location: Droegeham (The Netherlands)

Post by Frysk »

Thanks!

I've adjusted the oil level (120mm) and it feels a bit better, didn't had a chance to ride it tho (its 23:01 at the moment, neighbours wouldn't appreciate it :mrgreen: )

A thing that I found a bit strange is that I only could find one shim? :blink:

I think I need to take a look at a exploded view for this one,

Thanks for the tips!
User avatar
Slick_Nick
Supporting Member
Posts: 1675
Joined: 10:06 pm Oct 22 2009
Country: Canada
Location: Calgary, Alberta
Contact:

Post by Slick_Nick »

The shims are VERY thin. Like thinner than a piece of paper most of em. Most forks have 20-25 shims
'00 KDX 220R
heckler
Member
Posts: 243
Joined: 11:15 pm Apr 06 2010
Country:

Post by heckler »

look into getting the right weight spring.

I farted around with valve stacks and shims with my KX450F fork, but it was the softer springs that made a world of difference.
Frysk
Member
Posts: 132
Joined: 03:02 pm Dec 04 2011
Country:
Location: Droegeham (The Netherlands)

Post by Frysk »

>|<>QBB<
heckler wrote:look into getting the right weight spring.

I farted around with valve stacks and shims with my KX450F fork, but it was the softer springs that made a world of difference.
I don't know what springs are in there now, not the stock ones thats for sure (Reiger suspension) but I don't wanna buy springs and then I discover that they are the same or heavier :s

I'm around 215lbs (98kg) and 193cm tall, not a real fast rider but not slow eather.
I mostly ride woods and (wet) bumpy sand.
What would you recommend ?
Also any ideas about the front tire for this kind of terrain? It must be a road legal tire because my bike has a licence plate and I don't wanna get pulled over for a tire (€140 - $180)
User avatar
Slick_Nick
Supporting Member
Posts: 1675
Joined: 10:06 pm Oct 22 2009
Country: Canada
Location: Calgary, Alberta
Contact:

Post by Slick_Nick »

They will NEVER check your tires if you get pulled over.
'00 KDX 220R
KarlP
Supporting Member III
Supporting Member III
Posts: 1484
Joined: 02:26 pm Jun 29 2005
Country:
Location: Alabama

Post by KarlP »

You could rig up a spring weight tester to get a pretty accurate number for your existing springs.

I think I would spend a bit more time with clickers and oil weight (not height). You might also look to the rear supension. Changing forks can have unexpected results. Depending on the forks and fork springs you could be riding high or low in the front. Adjusting the rear might put things back in balance and make the front work better.

I think you might need to visit a local shop for a front tire selection. They should be more knowledgable about what is appropriate on the streets and trails of Droegeham.
'08 KTM200xc
'99 CR/KDX Hybrid with that RB stuff done to it
KX100 for the boy
User avatar
Mr. Wibbens
KDXRider.net
KDXRider.net
Posts: 4884
Joined: 02:57 am Nov 07 2004
Country:
Location: Playing in the Poison Oak
Contact:

Post by Mr. Wibbens »

>|<>QBB<
Frysk wrote:
A thing that I found a bit strange is that I only could find one shim? :blink:

!
as old as those forks are, I'm surprised you found any shims
Warning! This member tends to use sarcasm as a regular form of communication. If a post seems offensive, before you panic and fly off the handle, re-read the post and imagine it being said with a sideways grin.
((Bike Profile))
((Pics))
FIVE OUT OF FOUR PEOPLE DONUT UNDERSTAND FRACTIONS
Frysk
Member
Posts: 132
Joined: 03:02 pm Dec 04 2011
Country:
Location: Droegeham (The Netherlands)

Post by Frysk »

>|<>QBB<
Slick_Nick wrote:They will NEVER check your tires if you get pulled over.
Never been to Holland I hear ?

>|<>QBB<
KarlP wrote:You could rig up a spring weight tester to get a pretty accurate number for your existing springs.

I think I would spend a bit more time with clickers and oil weight (not height). You might also look to the rear supension. Changing forks can have unexpected results. Depending on the forks and fork springs you could be riding high or low in the front. Adjusting the rear might put things back in balance and make the front work better.

I think you might need to visit a local shop for a front tire selection. They should be more knowledgable about what is appropriate on the streets and trails of Droegeham.
Thats not a bad idea, but the bike is quite good in balance at the moment (at least 20times better than with the previous fork)
only thing now is that it absorbs the small bumps (branches, small holes etc) a bit better

>|<>QBB<
Mr. Wibbens wrote:>|<>QBB<
Frysk wrote:
A thing that I found a bit strange is that I only could find one shim? :blink:

!
as old as those forks are, I'm surprised you found any shims
Yeah that's what I thought.. I think the thing I've found isn't even a shim.
Post Reply