250-500cc Suspension issue solved !!!

[huskydude59]

Hi every one... I own a WR300 2010... Much complaining has been offered over the harsh ride of the KYB fork... Me included.. The root cause is the oil... I drained the oil from my fork and pumped it dry and grabbed a bottle of 5wt supposedly. when i went to check it out i noticed that there was a differance in the nature of the fluid.. So i took it to work and put it thru the viscometer, there was a major difference between the two oils.... the oil removed from the fork did not flow like the new oil and was actually thicker in it rheology..
Be extra careful.. I am going to try running 2.5wt at std oil level.. 130mm. there is a noticeable difference feel in the fork action now... SO BE AWARE

 

[windsurf]

Funny you should say that. I also have a 2010 WR300 which the Kayaba forks never worked well on. I played with compression and rebound settings but it always felt harsh and hard on compression particularly on rough small rocky tracks. Also the sag never seemed quite right. Changed the fork oil at the weekend and the old oil looked and felt considerably thicker than 5wt, more like engine oil. Anyway I rode it yesterday and what a transformation with a much smoother fork action throughout the stroke.
It certainly is worthwhile checking, I would have thought that the dealer who I bought the bike new from would have put the correct oil in or maybe they come from the factory with a heavy weight oil?

 

[raisrx251]

That stock KYB oil is like Honey compared to most oils. Did you have to add anymore rebound?

 

[pvduke]

most oil thickens through use due to contamination. change the fluid and get everything spotless including valves and pistons after the first few hours- this is key! keep the fork/shock internals clean and oil fresh, makes a BIG diff!

 

[Motosportz]

Try the Amsoil suspension fluid, awesome stuff. SLICK.

 

[lankydoug]

I have about 100 miles on my 09 WR250. It is a little harsh but not unridable or as bad as some say theirs is. One suspension tuner said the factory fork springs were too stiff for my weight another said they were too soft. I feel the rear spring is too soft and I have the correct spring (5.6) for my weight (about 200lbs). I know when I put the stiffer rear spring on it will make the front seem softer which is what it feels like it needs. I was thinking of just changing oil and playing with the adjustments and see how close I can get it. Are you suggesting that the oil change will get me close or am I wasting my time?

My GasGas is sprung 46 front and 5.6 rear and it feels perfect to me.

 

[pvduke]

doug (and all) - after break in, like a few hours or so of good solid riding- take apart your fork/shock and CLEAN everything spotless. the valving MUST have spotless fluid to work propperly. things can either get clogged so it wont flow or propped open. do same BEFORE ya send it out. many complaints can be cured with new oil and spotless internals. ya change yer engine oil, why not the boinger oil? it gets worked at LEAST as hard, and, wait for it...has no filters.

suspension rules of thumb:
* springs hold the bike up.
* dampers control wheel speed/ride quality.
* ya cant damp in/out the wrong spring and vice versa

numbers are for referance and keeping track of baseline settings, yeh, there's the whole ballaprk thing and one can get close guessing or recomending based on experience but a little is a LOT....and, ride what FEELS best. mreeep!

 

[lankydoug]

doug (and all) - after break in, like a few hours or so of good solid riding- take apart your fork/shock and CLEAN everything spotless. the valving MUST have spotless fluid to work propperly. things can either get clogged so it wont flow or propped open. do same BEFORE ya send it out. many complaints can be cured with new oil and spotless internals. ya change yer engine oil, why not the boinger oil? it gets worked at LEAST as hard, and, wait for it...has no filters.

suspension rules of thumb:
* springs hold the bike up.
* dampers control wheel speed/ride quality.
* ya cant damp in/out the wrong spring and vice versa

numbers are for referance and keeping track of baseline settings, yeh, there's the whole ballaprk thing and one can get close guessing or recomending based on experience but a little is a LOT....and, ride what FEELS best. mreeep!

I get how it all works, what I was getting at was can I even get close without a re-valve? There was no way with my GasGas because it was sprung and valved for a 145 lb rider. I'm not the least bit afraid of servicing my forks but if I was going to have to send them off anyway for a re-valve then why bother. Is there any 200lb riders that have made the stock valving work and if so what spring and oil worked for them?

 

[pvduke]

if ya have the correct spring? yes! depends on your style/terrain. service it, get the correct ride height, then fiddle with the clickers. i also see your point etc. if you go way up or down on the spring rate you'll be out of the adjustability window of your valving in some cases for the part of the stroke the clicker/stack etc affects.

on one of my hard-enduro honda 2T's i had two sets of softer fork and shock springs. one for nasty stuff in Az and Wa etc and one for more open stuff like mojave etc... never touched the valves, they had tons of adjustment. im 160# so i was in the engineering ballpark and adjustability window for the valving and could make it work fine for me.

YMMV, just my .02, etc. etc....ya get that track cleared yet? mreeep!

 

[lankydoug]

if ya have the correct spring? yes! depends on your style/terrain. service it, get the correct ride height, then fiddle with the clickers. i also see your point etc. if you go way up or down on the spring rate you'll be out of the adjustability window of your valving in some cases for the part of the stroke the clicker/stack etc affects.

on one of my hard-enduro honda 2T's i had two sets of softer fork and shock springs. one for nasty stuff in Az and Wa etc and one for more open stuff like mojave etc... never touched the valves, they had tons of adjustment. im 160# so i was in the engineering ballpark and adjustability window for the valving and could make it work fine for me.

YMMV, just my .02, etc. etc....ya get that track cleared yet? mreeep!

That's what I was hoping for. The springs on my Husky are only off by one step in stiffness and most say they are valved way to stiff so you would think it would work out. My Gasser was off by 3 spring stiffnesses so even if you put the correct spring in there you would never get there with the dampening especially on the rebound. I'm going to try it on the Husky by gosh and if it doesn't work then Im out some time and some oil. (no big deal)

 

[pvduke]

that's the spirit!!!

 

[Arctra]

Interesting reading guys. I really struggled with my front end feeling harsh, but never thought to see what the fork oil was like as the bike only has just over 1000km's on it. If it's like syrup as you have found, that might be part of my problem. I am well outside "the window" of tuneability though, weighing in at about 275lbs (125kg). I have pretty much resolved to get my springs replaced and get Race Tech Gold valves put in by a reputable suspension tuner. Will cost a bomb, but I figure it's worth getting it right... the just service the fork oil regularly apparently

 

[lankydoug]

My 09 Wr250 has the Zokes and not KYBs but changing out the break in oil is recommended for any fork. I just bought 2 quarts of Yamalube 5w fork oil and from what I have heard the 50mm Zokes do a little better with a little less oil (more air gap) so I will give that a try while I'm servicing them.

 

[huskydude59]

Well all in all.. this does answer some serious questions on how to deal with those problems of harsh fork feel and vague handling. I never really thought of just going back to the basics..big lesson learnt.. if your clickers dont give you the feel . go inside and have a look... it might be as easy as fork oil...go figure !!! At least now i can start going riding and try to get my mojo back... It is just unbelievable how your confidence gets drained when you can't push your own boundary. And some of us just think we are getting too old... Bullshit !!! I'm not too old...

 

[Vinduro]

suspension rules of thumb:
* springs hold the bike up.
* dampers control wheel speed/ride quality.
* ya cant damp in/out the wrong spring and vice versa

Check the technical forum for my recommendations on suspension spring setup. Sags are very important. I would think .46kg springs would be heavy for riding offroad even for a 200lb rider. I ran .42kg springs on my KTM 525EXC and I weighed 180lbs. I couldn't get the correct static and rider sags with a heavier spring and my cornering suffered greatly. I did find that on my Husky that I had to go down one spring size on my fork but way up on my rear spring. I went from a 5kg to a 6kg on my wr150. My bike is plush and compliant while cornering like crazy. No head shake on straights.

 

[ohmygewd]

Harshiness = spring vs stiffness = damping.

Before spending any money on valving, I would recommend three things:
1. Get the correct rear spring for you weight.
2. Set the the rear sag (both free, static and race sag) correctly).
3. get the correct front spings for your weight.

Without the correct spring rate for your weight, no amount of valving or fork oil weight will remedy the action of your suspension unless this is corrected.

Before going down the valving route and the spring rate is correct, l would pay attention to fork oil weight (viscosity) and fork oil level(air gap) as they are as important if not crucial in the setup of your fork as this determines the speed or action of the fork via the damping, last 1/3 of the fork action and the bottoming resistance.

Here are my top tips:

1. You really need a stretch of dirt/trail to test the action of your forks as pavement/flat grass area will not show or feel any changes you've made. If you can find a good test track that has small ruts, rocks and a braking corner then this would be excellent plus a consistent line - you are testing the feel of your suspension rather than bike speed.

2. Start with a 5wt of the one brand remembering there are discrepancies between each manufacturer so stick to one brand if possible (never mix brands) - 2.5wt is too thin and probably blow thru the valving whilst 20wt is too thick and will cause hydraluic type lock through the valving.

3. If you find that 5wt is too light and 10wt too heavy, mix 5wt and 10wt together which will roughly make 7-7.5wt. Never mix 2/2.5wt with 5wt as this thins out the 5wt to around 3wt.

4. Work with a good baseline in fork oil level between 100mm (firm) to 120mm (plush)...this is known as the air spring which controls the last 1/3 of the fork action, determines bottoming resistences which you will feel the effect when braking from high speeds into a low speed corner and heavier fork springs do not make one ounce of difference in this part of the fork action but small increments of 5ml oil will!! PS Too low of fork oil level will risk in blowing seals.

5. Change your fork oil regularly at least once a year if you ride regularly throughout the whole year.

6. When talking about hi or lo speed damping just remember high speed damping is like hitting a series of rocks on the trail whereas low speed is like hitting ripples on the trail..all to do with the speed of which the suspension travels - this is considered the mid stroke of the suspension.

7. Know what exactly is happening i.e. click your rebound damping all the way in and hit your test track, record the feeling and then wind it all the way out. Do exactly the same with compression clicker BUT NOT ALL AT ONCE!! Do the same at the rear and what you are establishing is the feel of the bike and determining the effects of how each damping control works. Rebound= the spring return rate whilst compression=smooths out or controls the oscillation of the spring.
You should treat your clickers as fine adjustments to the conditions that you ride but not all conditions.
When people talk about vague feeling in the front suspension, this is more to do with rebound damping rather than compression (unless you are a road racer or track rider).

If you are at point 7, then you are ready to tinker with valving...remember this will effect the fork oil level too...have fun.

Sorry too waffle (note l'm no suspension expert either just a laymens view!!!)

 

[ohmygewd]

Whilst l'm on a roll here :
*You may have heard of two of these definitions and sometimes all three so this my take:
Free Sag - this is the first measurement of the overall rear suspension travel with the bike on the stand and the rear swingarm free of any load or stiction.
Static Sag - this is the second measurement with the bike on the ground and the difference between free sag and the now with the bike's weight - good baseline is 15 to 25mm.
Race Sag - this is the third measurement with the rider on the bike MINUS the static sag - good baseline between 90-105/10mm
** Always warm up the shock/forks before taking measurements by bouncing the bike, this will reduce stiction therefore more accurate reading.

All the above will determine whether your OEM rear spring is correct which directly effects whether the front springs are correct - you cannot change the rear spring rate without effecting the front spring rate and vice versa i.e go harder on the rear will result in going harder at the front as well.

Preload is the amount of force applied to the spring without any rider weight (hence the name Pre - Load). Typically on the rear these are the collars on the spring which you first fiddle with when setting the race sag on your bike - remember this does not raise the ride height of the rear (if it does then you have too hard of a rear spring)!!!
To adjust preload on the front, these are set by using spacers which you may have come across in other forums that use pvc tube cut a various length's (10 to 30mm), that the fork springs sit on (guys with 45mm zoke's would have seen them as std) - not recommend unless you really know your suspension back to front whereas all sportsbike have preload adjuster (these are the bolt like adjuster that when you screw in or out you count the lines).
IMHO, forget preload adjustment on the front and concentrate on the rear preload adjustment.

You might come across spring terms as progressive and linear:
Progressive=a spring that stiffens at the end which visually is a spring that starts off evenly coiled and then progressively tightens up or dual rate springs.
Linear = as the term suggest is a spring that is evenly coiled or same spring rate throughout the length of the spring
Which one? I personally go for a linear spring anyday even if they feel a little harsh in certain conditions as it's one less factor you have to deal with when adjusting damping as a progressive spring by it's nature is a change in the spring rate and if you don't know when that change in the rate occurs in the stroke of your suspension...well to coin a great Australian saying "Mate, this is farked!!"

As for valving, well that's where the black art of suspension tuning occurs as the thickness and amount of shims (or stack) effects the flow rate of the fork oil therefore the action and damping all of which l have no idea or intend to learn.BUT..if you understand the components that effect your suspension and how they translate into the quality of, or lack of, your riding, then you can go to your suspension guru with the full knowledge you will be both on the same page and he/she really knows that this customer will pick up the the changes he/she has made rather than ripping the customer off (see comment below).

So the long and sort, understand your suspension before splashing out the cash in sending them out to a tuner who will probably scratch his head talking you as he can't understand what you want and so they set your forks or rear to baseline for the imaginary standard rider (hence the customer feels ripped off).

PS. Dirtbikes are easy, you should try friggin roadbikes OMG!!!

 

[lankydoug]

Here is a basic fork seal and oil change, you could of course change the spring while you were there.

http://www.youtube.com/watch?v=Y43k1qFVGW4&feature=relmfu Cartridge Type

http://www.youtube.com/watch?v=G0dLM_IoIOQ&feature=relmfu Twin Chamber

 

[huskydude59]

Since I have owned my WR300 i have been around the world on such issues of handling and suspension.. which now by definition are the same thing to me.. It is easy to get caught up in setup's of people who race, people who "ride fast" and then you have people like me... I am a trail rider that is 52 years old, I have my days when i can hook in and there there is the days when i am just happy buzzling along at my 80% rule.. The trick here is to know where you want to be. What makes the bike feel good to "YOU". If you use this rule then you "WILL" become better at riding, simply because you feel you are in control.. When i write BETTER, i mean you will enjoy all of your riding because you have some degree of synergy between you and you weapon.. This is where it has gone pear shaped for me.. I have stuggled so long with this issue my riding confidence, and skil has taken a bit of a hammering... So where to know... Back to the beginning.. Back to the start, Slow and Steady, building my speed and my confidence. The difference will be I now have more knowledge than before, and not to go thru the same problems... I HOPE...

 

[lankydoug]

I'm 47 years old and right there with you. I went a hell of a lot faster on a yz125 when I was 16 years old and didn't even know you could change the fork springs, my bike had no clickers and the only reason to buy fork oil was if it all leaked out. The way to go faster was to twist the throttle and keep it twisted. Now days playing with my bikes set up is fun and may help a little but working on my fitness and skills is by far the best plan for results.