Yet another RSU fork post...

[Colorado Mike]

I know there are too many posts on these dang forks (the Right Side Up ones) but I still have a few questions. What I know so far is that I want a pretty plush ride for the rocky areas I'm in, I ride an '04 220, and I ordered the .38 Kg/mm XR400 forks from servicehonda that apparently will be from 530 to 535mm long. Answers to any or all of the following stupid questions will set my mind at ease:

1) since the springs are stiffer, I should consider 7wt oil vs. the 5 wt from the factory. To get the old oil out, do I have to remove the forks and turn them upside down? My old bikes had drain screws on the bottom of the legs, these don't.

2) The manual says oil level should be 85-100 mm. I take this to mean measured from the top of the inner tube with the fork compressed and the spring out? if this is true, the 100mm figure means you have less oil in it than you do at 85mm, right? If so, I take it to mean Canyn likes less oil in there than the specs call for.

3) The manual shows a spring holder tool that helps hold the spring out of the way so you can get a wrench onto the damper rod and take the cap off. I've heard this isn't really necessary, is that true?

4) I don't really need that long damper rod tool unless I'm totally disassembling the forks, right?

Thanks for bearing with me. These things seem to be a little more complicated than the older style forks I was used to, but I'm probably over thinking it.

[Mark W]

1. Oil viscosity is a personal choice. I don't think I'm good enough to tell the difference but we'll see.

2. That is oil level measured from the top. Once again, this is a personal choice type of thing.

3. Not necessary at all. I just used an open ended wrench to keep the spring out of the way. I can see using a thin piece of steel or aluminum that is wider than the opening at the top of the forks, that has a notch cut out of it a little wider that the dampin rod would be even more helpful. The open ended wrench tended to slip.

4. I don't think you need the long damper rod specially made for this. You can make you own if you access to metric couplers and very fine threaded nuts. I'm thinking this would make the job easier on the "put it all back together" sequence.

Mark

[Indawoods]

Heavier oil provides more dampening. With heavier springs, heavier oil should not be necessary. It's your call.

* Remove the forks to drain the oil by removing the springs, turning upside down and pump the rod until no more oil comes out. You do not need the rod holder but it does make it easier whenever you have to pump the rod.
* Spring holder... not necessary at all. Hold the spring down with one hand and put your 15mm open end wrench on the nut, release the spring and turn cap off the rod.
Oil level... less measurement means more oil. The more oil, the more the dampening and bottoming resistance.

The spacer length, oil level, oil weight, rebound and compression settings all play a role on how your forks react with any spring rate. The springs are only one part of the equation ... they all play a role and there is not a magic formula anyone can give you, only starting points so your not too far off track. Play with all the setting and have fun.

* Just did it night before last to break down my forks to send off to Fredette...

[KDXer]

My .38's were from memory closer to 500mm than 530mm.

Part number ending in 671 are the .38's.

[89kdx200rdr]

sorry this is no answer but is an answer. you just have to try all the combos and see what you like. its a pain in the butt but one day you will find what you like or get tired of trying combos and learn to like one.

depending on how and what you ride in i would run a .40 with 5wt at 85mm if you weigh 175. but that is like asking for jetting help. too many variables.

[KDXGarage]

Too many posts on forks? No way! I say more posts! I could talk about this stuff until you are blue in the face.

Though you do not have to remove or change the oil when you change the springs, I will assume that they have the stock oil in them. If so, then I say it is way past time to change it. If you do want to change the oil, then you will need to take the forks off, and empty them out. If possible, turn them upside down and let as much drain out as you have time to wait. The longer you let them drain, the more old oil will creep out. There may be some bits of metal flashing in it. Without getting too technical, those little bits can creep around inside and cause havoc.

Oil weight is something you can play around with. You may want to check out the oil weight chart I posted a link to about 4 months ago. Check out the 40 degrees Celcius ratings, and you can see how the various oils match up according to whoever wrote that chart. No need to look at the 100 degrees rating because if your forks are 212 degrees, then you have more problems to worry about than fork oil.

You are correct, in that the measurement is taken with the springs out and the tubes compressed together. Any measurement is taken to mean "from the top", as in 85mm from the top - 100mm from the top.

DO NOT put more oil in there than the smallest measurement. Within the adjustable range, more oil mainly causes it to be stiffer in the last 1/3 of travel. Though it has an affect on the lower ranges of travel, it is really used to reduce bottoming. You should be bottoming out lightly on your toughest trail obstacles. If it is bottoming out harshly or often, raise the oil level. If it never bottoms out or never gets close to bottoming out, raise the oil level. You can take off one fork boot and put a zip-tie around a fork leg to see how far it is traveling. Do this without the spring in and measure, then compare future readings to that number. Don't try to compare it to some number in a manual about travel. Measure it for yourself.

As a substitute for the spring holder tool mentioned in the manual, you can use an adjustable wrench or an open end wrench. I have used both with good success. Check out the first picture on the 1993 - 1994 KDX200 forks section of my website. I have a picture of the open end wrench in use. it is 16mm on my forks, but that may not apply to your forks.

http://jasonwhokdx.home.mchsi.com/E/E.html

Which damper rod tool are you referring to? You will not need the 57001-1245 tool. The 57001-1298 tool that threads onto the top of the damper rod is handy, but not required. It would be used right before you put the springs back on. After you put the springs on, it is a small hassle to get the end of the damper rod above the top of the spring. I have used needle-nose pliers to come in between two spring coils, lightly grab the top of the damper rod (above the threads), then spin the spring downward until the pliers are at the top of the spring. I then reach with my other hand down inside the top of the spring and grab the top of the damper rod, releasing the pliers. You can also flex the spring to the side to hold it still until you grab the rod. After I have the top of the damper rod, I pull up on it, allowing the spring to go down. I then put the open end wrench under the rod nut, and continue from there.

If you were referring to the 57001-1245 tool, that is like the fork tool shown on the FRP site. That is used when you are going to take the base valve assembly out. You don't need to do that to change the fork springs or oil. Well, on the oil you should, but that is another story.

Like several people have already mentioned, they are many variables. It would take a lot of money and a lot of time to get it perfect. I think pretty much everyone who has gone with stiffer fork springs, loves them. I think you will, too.

I don't know if this will help on your conventional forks (Right Side Up if you will), but one thing I would like to suggest is that you loosen the upper triple clamp fork tube clamping bolts, then loosen the fork caps, then loosen the lower triple clamp fork tube clamping bolts, then slide th fork legs out. Also, be sure to take off all the other stuff (wheel, caliper, etc.) before you take the tubes out. After you take the tubes out, take the fork boots off if you are going to change the fork oil.

Mark W, the rod puller tool is 10mm x 1.0mm if you ever want to make one. They are only $11.07 from BikeBandit, so it may not be worth the trouble. The spring holder tool is only $10.00. They are a couple of the very few reasonably priced Kawasaki special tools.

[Colorado Mike]

Thanks guys, Great info as usual. I understand it a lot better now. Yeah, my forks still have the factory oil in them, so I wanted to change it anyway. I'm looking forward to trying it out with the stiffer springs. I really don't do any big jumps or anything, but the forks compress way to much when I'm braking on steep bumpy downhills. This makes for some anxious moments.

Thanks again,

[Anonymous]

Pump the damper rod a lot to remove the oil. Be sure to move it all the way in and fully extend it. My manual says 10 times, but that is not really enough. If you can leave them upside down in a bucket for a while, that will help to remove the old oil.

I know it sounds like I am recommending that you go through a lot of trouble to remove a little more oil, so let me explain.

Last fall, I changed my fork oil, putting in fresh oil. I pumped the damper rod more than the manual says and tried to let a lot drain out. I bought the bike used, and the guy said it had Race Tech Gold Valves in the forks and shock. Last week, I decided to see if it really did have Gold Valves in them. I didn't ride the bike with the fresh oil, so when I dumped it out as part of checking for the GV's, I was surprised to see a little gunk in the supposedly fresh oil. Again, these forks had "fresh" oil and ZERO miles on them.

It made me a firm believer that to get the forks really clean of the old oil, further disassembly of the forks is required. I had read that a good bit in suspension forums, but I thought it was a bunch of trouble. They are right, but it is really the way to go for a better cleaning.

That is just something to think about for the future. You have enough to worry about for now. With fresh oil and new springs, you will be thrilled.

[89kdx200rdr]

if you want to spend the time and money and havent changed your fork oil in a while you could get extra fork oil and flush them out. just do everything like you were changing the oil but dump it and then refill.

[Indawoods]

I would cut the cleaning oil with a 1/3 kerosene... it will loosen any deposits of gunk...and pump the sh!t out of the rod, let it sit and then pump it some more. Then dump it and let it drain overnight.

[89kdx200rdr]

cool we can say sh!t on this forum

[canyncarvr]

No $#*^!

An '04 is unlikely to have a whole lot of gunk buildup in the forks, I'd guess.

So, the simpler oil change method (turn 'em upside down, cycle the rod a few times) would work to a better degree than, say, a bike that hadn't had the fork oil changed for several years. IMO

Make sure you get the bottom clip out with the old springs. Clip it securely to the new springs. If you don't get the clip out with the old springs...get it out of the tube before you put the new springs in.

Yeah. I like the 'bigger' air shock on the RSU forks. Yeah. That does mean less oil..measured to a lower level...a larger number.

As stated...all a matter of personal preference.

You'll like your new springs, I'll bet'cha!

[Colorado Mike]

thanks. I'll make sure to keep track of the clip. I haven't seen the springs yet. I ordered them on the 11th. Hopefully they'll show up soon and be the right length.

Thanks for the info,

[canyncarvr]

Another BTW...something I don't see mentioned in this thread, but is a commonly used method for measuring fork oil.

You mention 'measure from the top'. The easiest way to do it is really not to meausure the fluid level directly at all.

Use some sucker thing (a big syringe from your local feed/grange store...a brake bleeder..etc.) with a piece of hose attached to constitute the level you desire. Overfill the fork, insert the tube you have already measured/cut to your spec..suck the excess oil out.

You DO pump the rod a good number of times after you put the oil it to make sure you get the air pockets out. You will be able to hear the change from full of air to not. You DO then let the fork sit for awhile (another IMO...ten minutes minimum)...tap the side a few times with a rubber mallet....before making that oil level determination. All in an effort to get the air out.

Inda said this in another recent thread, but on reassy, be sure to hold the cap and turn the tube to tighten the cap. Don't hold the tube and turn the cap.

One more thing to keep in mind (well, for now). Keep in mind that when you remove the cap from the rod it is likely that the nut will thread down the rod and lock at the end of the threads before you have enough 'hold' to break the cap loose. That means that when you put the cap BACK on, you will have to thread the nut back up to where it came from. That may feel odd to you when it's happening. You'll thread the cap all the way down until the rod bottoms (well, tops actually) out against the inside of the cap. Then there is still a lot of twisting to do to get the nut back up against the cap.

You may wonder what's going on.

And the first 'oomph' to get the nut UNSTUCK from where it's jammed may take a good bit of force, too. As much as it took to get the cap UNstuck from the rod.

Sorry...that's rather a long-winded way of saying not a whole lot. Hope it makes a tad of sense.

Aha! One more thing. My 'H' forks ('00 200) have drain screws. Odd that yours wouldn't. The flush idea is a lot better one anyway.

Have fun!!

[Colorado Mike]

Thanks again CC, that bizniz with the nut and cap makes sense, and I'm glad you mentioned it. My springs showed up today, so I'll gather up the other stuff (rigged up oil level gizmo, PVC, etc.) and get them swapped out. I measured the new ones and I get about 20.2 inches, times 25.4, I get about 513mm. I hope that works, for some reason I thought they would be shorter, but in re-reading Kay Dee Exer's post they sound right. I think I'll get my welder freind to make me up a rod holder tool. I'll probably go with 7wt oil, I can always change it if it's too weird.

Oh, and on the back edge of the lower fork leg, near the bottom there is a mysterious bulge in the casting. It's blank, but I bet it's where they used to drill and tap a drain hole. Deleting that process probably got some KYB exec that never sat on a dirtbike a nice bonus.

Thanks for the good stuff.