Fork oil height H model

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firsthere
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Fork oil height H model

Post by firsthere »

I'm not sure if this has been addressed, The service manual states the range as 85mm to 100mm. My owners manual, that came with the bike, says 85mm to 135mm, Racetac recommends 140mm. Mines set at 100mm w 7.5w for rocky/rooted trail riding. What are others setting theirs, and why?
Last edited by firsthere on 12:33 pm Dec 26 2020, edited 1 time in total.
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Re: Fork oil height

Post by KDXGarage »

Which KDX??

I moved this to General Q&A. The Reference Section is SUPPOSED TO BE :-) more about publishing facts instead of questions.
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firsthere
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Re: Fork oil height H model

Post by firsthere »

The reason for asking, on my other bikes with conventional forks, I run upwards of 140mm for a more supple ride on rocky terrain. Intuitively, it would seem the same oil level parameters could be used on the KDX (up until the point it starts bottoming).
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Re: Fork oil height H model

Post by KDXGarage »

I think that would be fine. Only going to 100 does not sound right.

Have you tried 5 weight?
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Re: Fork oil height H model

Post by firsthere »

Have not tried 5w, how does that affect the rebound? I also wanted to ask about drilling the piston for better flow plus a shim stack to go with. I did the Bornyack mod similar to this on the 650R, it was a noticeable improvement.
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Re: Fork oil height H model

Post by KDXGarage »

Lighter oil will be less damping. Thicker oil is more damping.

Which spring rate do you have and what is your weight in full riding gear?

What is a Bornyack mod?
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firsthere
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Re: Fork oil height H model

Post by firsthere »

quote=KDXGarage post_id=213505 time=1609352724 user_id=6252]
KDXGarage wrote: 01:25 pm Dec 30 2020 Lighter oil will be less damping. Thicker oil is more damping.
Come on man, :wink: my question was intended to address the overall affect on compression, rebound, springs and bottoming resistance with lighter fluid. I'm basically looking for an entirely revised fork setup which may involve the XR650R type modifications. Although there are no rebound adjustments other than fluid weight on the KDX.
KDXGarage wrote: 01:25 pm Dec 30 2020Which spring rate do you have and what is your weight in full riding gear?

200lbs full gear, with stock H fork springs. I'm leaning toward the lighter end of the 39/41kg range to replace them.
KDXGarage wrote: 01:25 pm Dec 30 2020What is a Bornyack mod?

http://www.borynack.com/xr650r/forks.htm.

This procedure helps reduce the harshness of the stock forks while still resisting bottoming. It involves drilling out the 4 piston ports similar to the gold valve to increase flow and fork reaction. Modifications to both shim stacks work in conjunction with the increased flow to remove the dampening spike at lower velocity's. This modification is done by many XR owners (including myself) with great results. This independent analysis of the modification was done by the restacker software company to present reasoning behind it.
http://restackor.com/Code/Sample_Applic ... /xr650.htm
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Re: Fork oil height H model

Post by KDXGarage »

No matter what you do to the stock piston, it won't compare too well to a Race Tech Gold Valve.
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Re: Fork oil height H model

Post by treelimb »

KDXGarage wrote: 06:04 pm Jan 01 2021 No matter what you do to the stock piston, it won't compare too well to a Race Tech Gold Valve.
I concur. I second that. Night and day difference. Even front and rear out and gold valve each using proper springs. Before long you'll have a $5-6000 KDX and your wife will axe you " why don't you just buy a new bike ?"

Crickets. The sound of crickets will permeate the air and you'll realize the affair/ fling/ love triangle that you've been having between the KDX and your wife. There will not be a true rebuttal due to your phone ringing because the local Kawasaki shop has given your phone number to a guy that wants to give you several totes/ boxes overflowing with KDX parts( swing arms, complete front end, tank, calipers,plastics, guards,wheels,handle bars,carbs, cables,new boxes of bearings,etc) and at that point you convince yourself that with the free parts you can subtract a few hundred dollars from the overall total spent during a total rebuild and then reply to the wife that
" I don't really have that much in my KDX because of all the extra parts hoarded over a 15 year period", overlooking the fact that her rebuttal could include the factual statement that new parts and bought/ donated old parts do not cancel each other out. Hopefully she'll overlook the double talk that you know you are guilty of. 50-50 chance.

It is at that point you return home from Kaw shop and you go straight to filing cabinet to insert new reciepts into the 2" thick folder of KDX expenditures.

Thankfully my wife approves of my love affair/ fling with my KDX.

I do often wonder if I'd be faster on a 21st century bike but I have first got to wring all I can out of the ol' girl cause she's been so loyal-

Now, if I can check with Ron Black and catch him while he is doing carbs my kDX will love me back even more.
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