2006 YZ250 KYB TC Forks

[christopher in tam]

I have a total of 3 riding days on my new 06 YZ250 and its been hard to get the suspension dialed in (kinda expected for a new bike). But heres what I find alittle weird...

The forks...
Out the box they have great bottoming resistance (guess they aimed at fixing 05's bottoming problem).
Mid stroke feel is odd, it isnt soft and it doesnt dive or anything but its feedbackless (if that makes sence). Turning in the compression clicker just makes the fork firmer on the top but doesnt help the mid stroke at all. Because of this lack of feedback in the midstroke the bike would handle like crap in whoops, allowing the rear to overpower.
So I added 5ml of fork oil in the outter chamber (through the bleeder) and this gave me the feedback in the mid stroke I was looking for. So I got that fixed.

But now heres the kicker, The fork still doesnt bottom (never). Seems I'm only useing about alittle over 10" of travel. Normally I would remove some oil to allow the forks to reach thier full stroke but then I will loose the mid stroke feedback that is so needed to make the bike stable. I have tried turning back compression clickers but this only seems to soften the first few inches of travel.

What gives?
Is this only happening because the bike only has 3 rides on it and still needs more breaking in?
Whats so different between the 05 and 06 KYB's?
Has anyone else noticed these same things with the 06?

 

[bedell99]

Before you go nuts you have to ride the bike for a couple of more days. I have now over 20 hours(On the hour meter) on my bike and the forks are well broken in. At 3 days they where just getting started. Give it a couple of more days of hard riding and they see where you are at. My forks where terribley stiff and now they are pretty good. I think adding oil to your forks made the bottoming even harder to achieve.

Erik

Erik

 

[christopher in tam]

Yes, I know adding the oil made bottoming harder to acheive but without the extra 5ml of oil the forks lacks feedback in the mid stroke and allowed the rear to overpower the front when in wet deap sandy woops. So its a cant win situation with the extra oil...

Let me ask you, since you have 20 hours on the bike already. Did your shock seem to break in faster than the forks? Have you changed anything with the forks as in oil level or anything? Now that they are broken in, can you give me a run down on what you think about them?

 

[MXP1MP]

Haven't done jack to my '06 YZ's forks and I've gotten them to bottom personally I think they feel great threw the mid stroke on both the 125 and 250. I want to know if anyone has taken them apart yet?

 

[christopher in tam]

MXP1MP, were yours overly resistant to bottoming during the first 3 days of riding?

Just trying to figure out (or hope) that mine will see full stroke after break in.

 

[bedell99]

I loosened up the compression and went in the rebound on the forks. Slowly I keep going in on the compression clicker. The shock definetly broke in a bit quicker. All I have done on the shock is turn out the HS compression about a 1/6 of a turn and 2 clicks out on the compression. The first couple of days I couldn't even come close to bottoming. the first day it was like riding a rigid, but I promise you they break in pretty nice and actually get pretty soft if you are a aggresive rider or weigh over 170.

Erik

 

[christopher in tam]

Since I have two aluminum frame YZ250 owners now on this thread.... What sag have you guys been running. I have noticed this bike is not too picky about its sag adjustment, as long as it has about 102mm or more its ok. I been running 105mm on a dirty bike, fully geared,, and dirty. It took 104mm to 105mm to acheive some rear end squat (for traction) when coming out of corners.

 

[MXP1MP]

Yes they did start to loosen up after about 5 hrs of use on them I didn't seem to really notice cause this isn't my first YZ in recent years so I guess i'm used to it being that way from new. I haven't done anything to them yet but i'm gonna adjust the sag settings on them now. I'm still trying to form an opinion about them but compared to my '04 KX these feel like 500 times better. So far i'm finding it hard to fault the suspenion they haven't done anything wrong..... yet :)

 

[bedell99]

I'm running 100mm of sag. I had to loosen the ring about 1 1/2 turns. I find the bike rides pretty good at 100mm. I weigh 155lbs, no gear and I'm 5'10"

Erik

 

[christopher in tam]

UPDATE:

The forks finally broke in nicely. Now they will reach the bottom of the stroke but I never get a bottoming feel, just a tap on the bottom at the most, and only on the very worst landings. They are equal and balanced to the rear and it feels very good. In the past I have had my hands on two retired AMA pro bikes and this 06 YZ250 has the same level of firmness and bottoming resistance as both of the pro bikes, (which says alot for a stocker). Overall its not plush, but its soft enough to never get hung up on any bumps, but its so progressive and loves to attack the track. If you get into race mode the suspension will be right at home.

Here are my settings...

Forks:
compression, 10
rebound, 6
oil level, added 5 ml over stock amount
forks slide up 5mm, right up the the line on the forks.

Shock:
Race Sag 103mm
compression 9
rebound 7
HS compression 1/2 turn from all the way in

Again, these setting will work on a motocross track with lots of hard hitting obsticles, might not be so great for off road trail riding.

 

[bedell99]

Mine are slowly starting to "over" break in. I remember when I got the bike and I was sort of freaking out that they where so stiff and people told me not to worry theu will break in. they where right and now they are becoming a bit too soft.

Erik

 

[christopher in tam]

Yeah...

Have you done a fluid change on the forks yet or lately? Fluid levels go down through time and that can cause a softer feel. I have noticed that my fluid level can drop as much as 5 to 10ml within fluid changes. And thats with perfectly good seals and changing every 3 months.

 

[bikepilot]

Fork oil can also break down and offer less damping over time.

FYI on the showa TC forks I've found softer compression springs (not fork springs) make a huge difference in initial plushness, but don't seem to effect botoming resistance. I don't know if the Kayaba TC's are the same, but it might be worth checking into.


good luck

 

[Pete Payne]

Christopher in tam , That looks like alot of preload on the shock ( I think you ment sag)

 

[christopher in tam]

Your correct. I edited it for the correction. Thanks :cool:

 

[Coop37]

added oil?

Did you say you added oil through the bleed hole? if so, I think you should have added it to the outer tube? and not through the bleed hole?

 

[steve125]

The bleed hole vents into the outer chamber.

 

[Coop37]

Humm? how would the oil level stay at 145-148mm if it bleeds into the outer chamber?

 

[steve125]

These are cartridge forks like the Showas. Outer tube oil is measured in CC's/ML's, not mm's from the top.

The inner oil cartridge is sealed off from the outer and is bled free of air. So the air bleed access is for the outer fork tube, not the inner cartridge oil damper. The fork cap air bleed hole does not vent/bleed the inner cartridge.

 

[christopher in tam]

Yeah, steve125 is correct.

By the way, while we have this topic back up... I just want to point out that since my suspension is even more broken (or worn) in my settings have changed some compared to the settings I put up a few post back. Here is what I run now...

All clicker settings are referred to from the fully wound in (clockwise) position. So if its 10 clicks, thats 10 clicks out (counter clockwise) from the fully wound in position.

Forks:

compression, 10 clicks out

rebound, 4 clicks out

Fork oil level (outter chamber), 340 ML (can very depending on your weight)

Forks slide up in the clamps to 8mm (which is 3mm higher than the index line on the forks, as seen in the picture on this link http://i17.photobucket.com/albums/b.../Picture229.jpg )


Shock:

Race Sag, 102mm

compression, 8

rebound, 4

High Speed compression, 5/16th of a turn out (from all the way in) which is basicly a hair more than a quarter turn out.

Here are some explanations and notes of why I settled on some of the settings used.....

Rebound at 4 clicks out fork/shock: The bikes fork & shock has a natually fast rebound, so fast that with stock settings it makes the rear feel unstable at times, and the front want to understeer under throttle. Also can seem to feel bouncy on big jump landings. When turning the rebound clickers in better things dont start happening untill around 6 clicks out. I found the fork and shock feel best at 4 clicks out, it feels much more stable and planted.

Fork oil level (outter chamber): The forks have a great feel and nice firm yet smooth ride through most of the stroke but they will still reach bottom reather easy in stock trim. The manual says the minimum fork oil amount is 300ml and the maximum is 380ml, with 340ml being the standard amount. Assuming the bike comes stock with 340ml since the manual claims its the standard amount but I found mine to be right at 300ml (minimum amount). That explains why it bottoms in stock form. I added 5ml at a time per fork leg untill the harsh bottoming was gone, yet still being able to reach the bottom meaning I am using the full stroke. For me (165 pounds) it likes 340ml (surprise, thats the standard amount that the bike should have come with!).

Fork height in clamps : In the stock position (which is with the forks flush with the fork caps mounting flange) the bike corners badly (and the fast stock rebound setting doesnt help any). I first moved the forks up the clamps to the 5mm mark (index mark going around the fork leg) and this helps alot but was still far from being nimble in the corners. It still wanted to stand up and shoot straight as soon as throttle is applyed, and if you laid it lower to battle this trait then the rear would slide out easy. So I moved the forks up further and tried different settings. I found 8mm to give the bike crisp handling that allowed me to get in the throttle hard in mid corner without it standing up or sliding out. And the nice part was it lost almost zero stability.


Shock Race Sag: Mags say to run 105mm and the manual claims 100mm. 105mm is way too low and left the bike jumping front end high too often. I always start at 105mm and work my way up (down in numbers) untill I find the best balance in the chassis. 102mm was the best all around setting, has good stability yet is still agressive in the corners and on the faces of jumps.

High Speed compression: With the stock setting the rear end felt good on little chop but would blow through its stroke on larger hits, hitting the bumper too quickly and then transmitting all that energy to the rider in the form of a kick. At 5/16 of a turn out (from all the way in) the rear end has a smoother transition from low speed to high speed hits and feels much more balanced with the forks. Also helps with the problem of the 06 YZ250's jumping front end high.

Low speed compression fork/shock: I look for the setting that gives good feedback to the rider (nice to know what your wheels are doing) without being harsh or too firm.

5-10, 165 pounds and getting fatter

 

[chrismxer]

I am thinking of getting an 06 yz 250. Do you guys notice any harshness in the rough chop or slap down landings as these forks break in? And how is the shock breaking in? I'm still a bit worried about the reports that the rear is a little harsh?

thanks, Chris.

 

[christopher in tam]

Mine is fully broken in now and its not harsh at all. But when it was new it was kinda harsh and stiff. They need a good breaking in before they feel normal. I think all the mags (like Mr Young at transworld) feel the YZ250 was firm and harsh because it was a new bike they were riding. If they would have put in a good 5 days of riding then thier opinion would change I'm sure.

Shock broke-in in about 4 days of riding and forks broke-in in about 6 days of riding.

Recently found out the bike likes the rebound cranked in. I now have my rebound at 4 (from all the way in) on the forks and 5 (from all the way in) on the shock. Bike feels much more planted and smooth through the chop.

Best thing about the YZ250 is with the aluminum frame, titanium shock spring and foot pegs, and all new suspension... its the most advance 250 to come out in 06. Suzuki is nice but still stuck on steal :| same with the KX. CR is nothing new. The YZ is the best for 06 when it comes to bringing home the most advanced 250 2 stroke.

 

[chrismxer]

Have you had the forks apart to see if they suffer from the same problems as the 05's (springs too short & bleed issues). One of the tuners on thumper-talk said the internals are very nice and are the most simular to works forks he's ever seen on a production bike!!

 

[Jim Havins]

If this were my bike, I would increase the rebound stack right now in order to run it a t 10-12 clicks out. At only 4 clicks, the rebound circuit is probably making your compression stiffer and not as sensative.

 

[christopher in tam]

chrismxer... No, I havent had them apart yet. I already purchased the tools needed to disassemble them but I'm waiting to put a solid 3 months on the forks before I service them. I did hear though that they fixed the errors that haunted the 05 forks but I dont know first hand... yet


Jim Havins... Yeah the low speed rebound adjustment also effects low speed compression, although I dont think this has become a problem yet. When cranking the rebound adjustment in on these 06 KYB's things dont start happening untill you get them to about 5 or 6 clicks out (from all the way in). I think maybe the low speed rebound may be allowed to flow to freely and this is why I must set it at 4 for it to feel normal. Like, I'm thinking whats 4 on these forks might be simular to 8 or 10 on other forks. This is judging strictly by feel, as I havent had these apart yet to really know. But the high speed rebound (the part that the piston and shim stack controls) doesnt feel too bad, maybe alittle on the fast side but not too bad.

Same goes with the shock, the high speed rebound feels decent enough but the low speed rebound was way too fast. It didnt start feeling right untill I had the rebound set at 7 out (from all the way in). As of now, it feels best at 5 (but can very with track and conditions). Check it out for yourself, next time your at the dealer walk up to a 06 YZ250 and push down on the rear, that sucker will spring back up just as fast as its pushed down. Stock they are set at 9 to 10 out and have almost no low speed rebound damping at that setting.

The low speed rebound on both the forks and the shock is so free flowing and fast that I think any adjustment over 10 clicks wouldnt even be noticable, its that bad!

By the way, does anyone know if these new KYB forks take the same type of shims as normal older KYB forks?