05 KX 250 fork upgrade

Just curious if there is a better fork upgrade for an 05 KX 250 without major mod's ? 

An upgrade for what kind of riding?

Just curious if there is a better fork upgrade for an 05 KX 250 without major mod's ? 

The KYB AOSS forks are very good units but a lot of people don't like the harsh valving in them. What kind of problems are you having with them? The first thing would be to make sure they have the right springs for your weight. You can also play with the oil level in the forks.   Or something more involved would be to get them re-valved(or do it yourself if you can) But I recommend going to your local suspension shop and see what they can do for you. I had my local Race Tech shop redo my 2006 kx250's suspension, forks and shock as the shock can have as much effect on the forks as it does on the rear of the bike. After it was all said and done and I got the bike back together it was a world of difference. That's my 2 cents on the issue.

I'm sure J will be in here with his experience at some point. You can also search for his thread in this section that was centered on the 05+ kx250 suspension.

Edited by moose_338

No matter what you swap in there, you'll still want it to be sprung an valved to your liking. Just spend the time and effort on the stock forks, unless they are damaged.

Gold Valves are great for woods, couldn't get them to work for mx though. Besides that, you'll definitely need springs, ics springs and a revalve. Pick a good suspension shop.

An upgrade for what kind of riding?

Medium MX,I'm an older fart just out having fun.

The KYB AOSS forks are very good units but a lot of people don't like the harsh valving in them. What kind of problems are you having with them? The first thing would be to make sure they have the right springs for your weight. You can also play with the oil level in the forks.   Or something more involved would be to get them re-valved(or do it yourself if you can) But I recommend going to your local suspension shop and see what they can do for you. I had my local Race Tech shop redo my 2006 kx250's suspension, forks and shock as the shock can have as much effect on the forks as it does on the rear of the bike. After it was all said and done and I got the bike back together it was a world of difference. That's my 2 cents on the issue.

I'm sure J will be in here with his experience at some point. You can also search for his thread in this section that was centered on the 05+ kx250 suspension.

The only problem I'm having as of now is a bad seal,the suspension is actually not too bad but I figured since this bike is a KEEPER I would like to get the best out of the suspension. I've read a lot of good report's on Race Tech also.Thank's moose

What kind of rep does Factory Connection have with the KX's ? There is a FC shop about an hour away which is very convenient but I don't know anything about them.This bike is awesome and deserve's good treatment. 

04-06 250f forks are the same as the smokers of the same year, am I correct? Do they make for a better fork upgrade for the 94-98 smokers? Don't mean to go off track a little.

Gold Valves are great for woods, couldn't get them to work for mx though. Besides that, you'll definitely need springs, ics springs and a revalve. Pick a good suspension shop.

Gold valves and correct springs is what I did and love it!

My Racetech guru can make your gold valves work amazing for MX. I watch him rip his MX track regularly and they work brilliant. Ben Lemay does great with his gold valves on the national level

Everyone has the right answers here. But if you do your fronts and not the rear, then you're just shooting blanks. They work together for a good setup.

^^^ 100% agree with above.I had that issue with my YZ 125,it's like wearing a size 10 boot on one foot and a 12 on the other,it just don't feel right.

Edited by Alan48

Springs, and heavier. The KX250's forks harshness is mainly from relying on the low speed compression dampening to do all the work. When sprung heavier then you can back the compression clickers out which will really smoothen the forks out. Springs are much more transparant than low speed compression. By going heavier springs and less compression the forks will feel much smoother, follow the ground better and have the same or more bottoming resistance but overall bottom resistance is also based on how much fluid volume you choose to run in the outter chamber.  Thats the route I went. I ride MX and I am very sensitive to my setup. I weight 150 and run .46 springs in the front and 5.5 in the rear. I was able to remove 2 to 3 clicks compression out front and rear. This was perfect. I did have to add a click more rebound dampening though as heavier springs always need more rebound dampening to equal the same overall rebound speed.

 

If you weight more than me and want to do it cheap you can get used .47 springs on ebay from KX450s from like 06 to 07 or 08 if I remember correctly. Also 05 YZ450's, again you might want to double check racetechs site to cross reference just to be sure

Edited by UpAllNight

I'm topping the scale's at 215 so it look's like I'm gonna have to change the front and rear spring's, but that's ok,I've learned that a properly set up suspension is the ticket for improving lap time's.Appreciated UAN.

I messed around with what UpAllNight is talking about.  Heavier springs and lighter valving.  I wished I tried it with the stock stuff on my KX250, but I tried it with the GV and got them to work a little better, but it always seemed I was either too soft or too stiff.  I had those forks apart 1000 times.

 

On my 05 KX125 I went the same route.  First I went with a little heavier spring.  Then disabled the bladders (not in your case though). Finally, I just removed 3 face shims from the stock setup.  Rode it last weekend and it felt better than my 250 ever did.  So try that with the stock stuff first before going with different valves.

 

Every time I rode someone elses bike, usually a heavier rider, the bike felt great.  That's what gave me the idea to spring heavier.  Then I came across some posts in the suspension forum talking about the same thing.  If I was to tune another set of those forks, I'd go up one spring rate, install a 2.0 Yamaha IC spring, remove 3 face shims, maybe change to a 2 stage, and start off with 280cc oil.

thank's for the oil tip,I had no clue where to start with the oil ratio and that was my next question.Appreciated.

04-06 250f forks are the same as the smokers of the same year, am I correct? Do they make for a better fork upgrade for the 94-98 smokers? Don't mean to go off track a little.

 

2004 and 2005 KX250F forks are open cartridge.  2006 KX250F is Showa brand twin cartridge.

 

2005 - 2008 KX250 two-stroke is KYB twin cartridge.

2004 and 2005 KX250F forks are open cartridge. 2006 KX250F is Showa brand twin cartridge.

2005 - 2008 KX250 two-stroke is KYB twin cartridge.

there are a set of 250f forks on craiglist, I'd say 04-05. Just wondering if they are any good for swappingor should I stick to my 94 forks. If so, I could make an offer than send them out along with my shock over the winter.

there are a set of 250f forks on craiglist, I'd say 04-05. Just wondering if they are any good for swappingor should I stick to my 94 forks. If so, I could make an offer than send them out along with my shock over the winter.

The 04 has a bladder and the 05 doesn't. I have a set of 04 in the garage. They are the same tube diameters as the 03+, I don't think they will just bolt up. Plus the brake line routing is the 04+ style.

there are a set of 250f forks on craiglist, I'd say 04-05. Just wondering if they are any good for swappingor should I stick to my 94 forks. If so, I could make an offer than send them out along with my shock over the winter.

 

Quick fork rundown:

 

92-95 125/250 KYB 43mm, mid valve introduced in 95

96-01 125/250 KYB 46mm

02-05 125; 02-04 250 KYB 48mm 03 forks no bladder

05-07 250 KYB 48mm twin chamber 

04-05 250F KYB 48mm

06-10 250F Showa 47mm twin chamber

06-?? 450F KYB 48mm Twin Chamber (different model than the 250 two stroke twin chamber)

 

(feel free to make any corrections)

 

If you were to do an easy swap, just find a front end off a 96-01 bike, same as the 250f stuff but no need to swap trees.  A better swap would be a twin chamber setup from one of the 4 strokes.  Should find plenty 06-07 250F stuff on Ebay.  For weekend warrior riding, the cartridge stuff is fine IMO.

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