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Hey dogger are the 250 and 450 stacks similar?

Well yes and no. It all depends what I am valving for but a general rule of thumb is that with the 450 and more power and torque the shims will be a little thicker...for example on the stack that was jsut posted 

2010 CRF 250R

 

Comp

10-44.2

34.15

32.15

44.2

42.2

40.2

38.2

36.2

34.2

32.2

30.25

28.25

26.25  

24.25

22.25

20.25

18.3

baseplate

 

 

Rebound

5-40.2 (plan to take 1 out)

26.1

40.3  

38.3

36.3

34.3

32.3

30.3

2-28.3 (plan to take 1 out)

27.3 (plan to take out)

26.3

 

I would make the following changes for a 450

CRF 450R MX Int

 

Comp

12-44.25

36.15

32.15

44.2

42.2

40.2

38.2

36.25

34.25

32.25

30.25

28.25

26.25  

24.30

23.30

22.30

20.30

baseplate

 

 

Rebound

2-40.25

1-40.20

26.15

40.3  

38.3

36.3

34.3

32.3

30.3

29.30

28.30

27.30

26.30

 

 

Hope that helps

 

theDogger

 

bo.jpg

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Hey Dogger and everyone,

 

I was in my shock today to revalve it for trail duty  and noticed this. A groove has worn into the side of the valve piston. Anyone seen this before. Can't understand how this happened. No weird markings in side the shock body. Looks like I'll need a new piston.

 

Had no choice but to put it back together, but I'm guessing this will affect performance some.

 

ben

DSC02228.JPG

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Isn't that the replaceable piston wear band, and the piston looks ok? Has to be caused by some internal contamination. You didn't find anything floating around? Checked all the internal cavities, reservoir and bladder?

Edited by Eddie8v

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Isn't that the replaceable piston wear band, and the piston looks ok? Has to be caused by some internal contamination. You didn't find anything floating around? Checked all the internal cavities, reservoir and bladder?

Yep, checked everything and didn't see anything. Oil even looked good, although a bit foaming, which I've just come to expect. Color was as good as new.

 

If it is replaceable, I didn't know that. Have a part number by chance?

 

ben

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I don't have a part number but I know they're a bitch to replace and I think there are positioning o-rings underneath it as well that likely should be replaced while you're in there. Best left to a professional, else you ruin the piston. Very tight deep fit on the solid hoop seal band. That's about the extent of my knowledge on this, sorry.

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I don't have a part number but I know they're a bitch to replace and I think there are positioning o-rings underneath it as well that likely should be replaced while you're in there. Best left to a professional, else you ruin the piston. Very tight deep fit on the solid hoop seal band. That's about the extent of my knowledge on this, sorry.

 disagree on this one eddy, get onto MxTech and get one of the low friction piston bands approx $35 from memory, very easy to replace just don't over stretch it installing it

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Hey Dogger and everyone,

 

I was in my shock today to revalve it for trail duty  and noticed this. A groove has worn into the side of the valve piston. Anyone seen this before. Can't understand how this happened. No weird markings in side the shock body. Looks like I'll need a new piston.

 

Had no choice but to put it back together, but I'm guessing this will affect performance some.

 

ben

Ben I would not be too worried with it. If you do not have any scaring in the body. I would check the shaft and make sure it is not bent.

 

Replacing them in not had if you have the tool which is not expensive. Basically its a tapered cone thats fit to the top of the piston. But the band in a plastic bag and put it in your pocket for a few hours to warm it up and slide it over. Suspensiondirect.com has the tool for $35.00 I have this an use the tool and it work great!

 

http://www.suspensiondirect.com/product/SDTPRI50/50MM-Piston-Ring-Installation-Tool-ea/

r30-7.jpg

 

They also have the 50mm Showa 2004 + DU piston bushing conversion kit, (I would buy from SDI before giving MXTech a Dime!) I have used these in the past.

r15-3.jpg

 

The 3rd option is call Joey at PC and order the updated piston with the rings and band already installed should be around $90. (These are basically are A-Kit pistons)

 

theDogger

Edited by theDogger

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Ben I would not be too worried with it. If you do not have any scaring in the body. I would check the shaft and make sure it is not bent.

 

Replacing them in not had if you have the tool which is not expensive. Basically its a tapered cone thats fit to the top of the piston. But the band in a plastic bag and put it in your pocket for a few hours to warm it up and slide it over. Suspensiondirect.com has the tool for $35.00 I have this an use the tool and it work great!

 

http://www.suspensiondirect.com/product/SDTPRI50/50MM-Piston-Ring-Installation-Tool-ea/

r30-7.jpg

 

They also have the 50mm Showa 2004 + DU piston bushing conversion kit, (I would buy from SDI before giving MXTech a Dime!) I have used these in the past.

r15-3.jpg

 

The 3rd option is call Joey at PC and order the updated piston with the rings and band already installed should be around $90. (These are basically are A-Kit pistons)

 

theDogg

Hey Dogger, cool info!! whats wrong with MX-Tech??

 

Nick

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Whats wrong with MX-Tech??

 

 

They did their best to stop this thread when I first started it! I won't go into details sorry!

 

 

theDogger

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They did their best to stop this thread when I first started it! I won't go into details sorry!

 

 

theDogger

  

The last thing Jeremy wants is guys figuring out that the wizard behind the curtain is just a normal guy like them.

guys i respect you! this thread and jeremy! from my behind the screen judgment!

i read this thread occasionally, i started reading it from page 1 the other day and dogger said that jeremy went the extra mile, when noone else would!

that raised the question! i dont mean to make this an open cnversation!

i guess a lot has changed over the years! including my self! i was new to this when i started this thread and i do it semi professionally now!

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Let me clear things up hear so this can be killed! I am referring to Actions that were suggested via emails and letters by different shops not just MXtech.

 

Jeremy at first was kool until he found out about this and also the misinformation that was being posted in the beginning from people associated with MXTech (John Curea) trying to confuse and discourage people from learning to work on their own suspension! I also believe if my memory is correct there has been some posts removed early on upon my request to Brian of TT. 

 

So yes you are correct that in the beginning Jeremy was mentioned as helpful but in the shadows MXTech was not happy!

So hopefully this will kill the talk in this thread about this!

 

The bottom line for me and this thread was to get tribal knowledge base started and hope for constructive input to help the masses. The suspension world in MX is just like the Liberals out there wanting to hide the truth and confuse people to keep control and the wealth.

 

This is the TeaParty Thread of suspension to expose the clowns behind the curtain! Knowledge is power and it something they are truly afraid of!

 

theDogger

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okey!! sorry for stirring the past!!

 

i was here to ask about the PSF!! just to change the subject, and be constructive for a change...

 

i been working on it for a few weeks to get to feel better with some testing and help from others....what did you do to make it work? 

 

Not much mentioned in this thread!! for the CRF

 

We closed the float alot to 0.5, anything less didnt work for whooped up unmaintained Hardpack!

Aslo more bleed through the bleed stack..

 

All these was with the 13 2 piece piston!!

 

Nick

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I have been getting a lot of PM's asking about the KYB AIR forks and setup. In all honesty I have to say that I do not have a ton of experience with them but from the ones that I have worked on it has been a real give and take. I will say that of the 14 or so that I have worked on or with we have scrapped them and gone to the Showa SFF. Hello eBay!

 

The KYB AIR fork is half backed in my opinion and the issues that I see and am trying to deal with are 

 

1-The MV piston has two rebound bleeds that is way to much and to get a rebound stack to work it has to be way to stiff. These need to be closed to get an acceptable rebound stack to work right

 

2-Because they are 100% air/oil forks you have to deal with the air spring that builds as the forks compress. Now comes the problem there is nowhere for the pressure to blow off thus creating that fine line between harshness and the forks being progressive. If KYB was to do it right on the production fork they would have two chambers for air pressure. One for low-speed and One for High-speed. What this translates into is no where for the pressure to blow-off in the high-speed. What does this translate into? Well for lighter riders, tying to find the balance between the air/oil level which is next to impossible. This is the harshness that is felt in the forks and transfers this directly into the bars. So what does the rider do they cut the air pressure down and now the fork is mushy and blowing through the stroke, so then they up the air pressure and now the forks hold up but now are harsh. 

 

Now bigger/heavier/faster riders this is not as much of an issue but it is still there.

 

So if you look at the Factories and what they are running ever team this year is running the Showa SFF or if they are running the KYB Air forks (look closely and you will see a Low-speed and High-speed Schrader valve and even in some cases last year and I have not really look yet this year they were experimenting with a blow-off reservoir. Of course these are Factory Only A-Kits!

 

Check out the gallery and the forks on all the major players bikes. http://www.vitalmx.com/photos/features/2014-Bikes-of-Supercross,37752/Ryan-Villopoto,72188/GuyB,64

 

theDogger

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I have been getting a lot of PM's asking about the KYB AIR forks and setup. In all honesty I have to say that I do not have a ton of experience with them but from the ones that I have worked on it has been a real give and take. I will say that of the 14 or so that I have worked on or with we have scrapped them and gone to the Showa SFF. Hello eBay!

The KYB AIR fork is half backed in my opinion and the issues that I see and am trying to deal with are

1-The MV piston has two rebound bleeds that is way to much and to get a rebound stack to work it has to be way to stiff. These need to be closed to get an acceptable rebound stack to work right

2-Because they are 100% air/oil forks you have to deal with the air spring that builds as the forks compress. Now comes the problem there is nowhere for the pressure to blow off thus creating that fine line between harshness and the forks being progressive. If KYB was to do it right on the production fork they would have two chambers for air pressure. One for low-speed and One for High-speed. What this translates into is no where for the pressure to blow-off in the high-speed. What does this translate into? Well for lighter riders, tying to find the balance between the air/oil level which is next to impossible. This is the harshness that is felt in the forks and transfers this directly into the bars. So what does the rider do they cut the air pressure down and now the fork is mushy and blowing through the stroke, so then they up the air pressure and now the forks hold up but now are harsh.

Now bigger/heavier/faster riders this is not as much of an issue but it is still there.

So if you look at the Factories and what they are running ever team this year is running the Showa SFF or if they are running the KYB Air forks (look closely and you will see a Low-speed and High-speed Schrader valve and even in some cases last year and I have not really look yet this year they were experimenting with a blow-off reservoir. Of course these are Factory Only A-Kits!

Check out the gallery and the forks on all the major players bikes. http://www.vitalmx.com/photos/features/2014-Bikes-of-Supercross,37752/Ryan-Villopoto,72188/GuyB,64

theDogger

I can only comment on the 'light rider' thing really, but being a light rider there is some merit in using lighter balance springs to lower overall pressure/rate, but keep the fork up in its stroke at the same time.

The less pressure you use, the more negative effect the balance springs have, thus that initial travel becomes so soft you blow through it easy, it's over 1/3 travel that is effected....

The balance springs are in a simple sense your spring pre load adjusters, the heavier the spring the less pre load.....

I found with stock balance springs it took around 31psi to fully extend the fork, that is the fork on its own laying on its side, so literally the pressure needed to overcome the balance springs. I had some springs made 25% softer, these took around 26psi to overcome spring pressure.

In reality, as you say, I think it is a big balancing act. In my opinion you have to chose an air pressure/spring rate to suit weight/terrain etc, much like you would a normal spring.

You then match balance springs to provide the pre load you want to get the sag/feel you need/want. (I know some woods guys want more pre load, running light Balance springs but higher air pressures, so the fork sits tall)

Then you tune in the oil amount for desired last 1/3 action.

My personal opinion is that people are using the adjustable parameters, air, and oil, to tune the fork in the wrong areas.

Air is spring rate

Balance springs are pre load (most people never change in spring fork as it is pre set, yet we fit the correct rate rear spring and adjust pre load with no thought)

Oil amount, mainly 2/3-3/3 travel but does have an effect elsewhere (Like a spring fork)

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Ok there is some truth to what you have said and I was going to mention the Balance Spring but in my case in the setups that I got working decent I blocked the rebound holes in the piston, removed the Balance spring altogether. 

What is happening with the balance spring is that since the pressure can't blow off it basically increases the the rates of the spring. It would be like taking the OEM 2.2kg Pressure Spring and replacing it with a 6.6kg spring.

 

Yes there is a very very fine line to the amount of air and oil.

 

I think that you will see Showa release a Air fork that has the two chambers that can be tuned separately and hopefully KYB will follow, but until that point I see the KYB AIR Fork as half baked! I think that seeing the factory pro's running the Showa SFF says a lot about the air fork. Even the fastest guys in the world do not like the air only fork.

 

theDogger

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Ok there is some truth to what you have said and I was going to mention the Balance Spring but in my case in the setups that I got working decent I blocked thIe rebound holes in the piston, removed the Balance spring altogether.

What is happening with the balance spring is that since the pressure can't blow off it basically increases the the rates of the spring. It would be like taking the OEM 2.2kg Pressure Spring and replacing it with a 6.6kg spring.

Yes there is a very very fine line to the amount of air and oil.

I think that you will see Showa release a Air fork that has the two chambers that can be tuned separately and hopefully KYB will follow, but until that point I see the KYB AIR Fork as half baked! I think that seeing the factory pro's running the Showa SFF says a lot about the air fork. Even the fastest guys in the world do not like the air only fork.

theDogger

Are the sff forks not 'air' still, the sticker I see says sff air.

Are you blocking off both bleed holes?

It is interesting you are losing the Balance springs, what pressures do you recommend for certain 'weights' of rider like that?

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SFF AND SSF AIR have price difference quite big to be available as production!

MB1 sells the sff air for a bit more than 8000$....

what heard from another thread is that Factory Yamaha startet running the PSF this season...

offcourse it doesnt mean they made it work!! could be like KTM with the Air Shock last year! it lasted

one race!

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