Fork Oil change question: with major questions now on internals

I'm working on my 2000's forks today and what I am finding is not the same stuff mentioned in the Clymer's book or the shop manual. Maybe someone has been there before me with different stuff, it wouldn't surprise me.

  I am just wanting to inspect things and change the oil to 5wt Honda Pro...which I did.   So it calls for 130mm to the oil level without the spring installed. When I put the specified amount...about 15.xx Oz of oil in, it leaves me about 70mm between the oil level and the top of the slider, without the spring or anything else in the fork... I have to remove about 5oz of oil to get to the level mentioned in the books...quite a difference from the book...

  The spring in the manual shows different winding on the coils and the book one is longer than the one I found, which has "08713-95/l541" etched into one end. It is straight wound, a single rate spring... Also I found two spacers in my stack...appx. 50mm each...I think one on the bottom and one at the fork cap. the book does not show it like that....

  I will now check all this by taking apart the other fork leg, too.... *very carefully* and noting exactly how it is put together...I think I have this first one right, but it never hurts to double double check.

   So, do you think I might have modified forks?   and how the heck to I arrive at what fluid level to use?  
  Thanks, Don Hanson

  Edit:  Now I have some SERIOUS questions that I'll add in another post below..

Yup, sounds like someone changed the springs at some point. Most aftermarket are straight rate, while the stock ones are progressive. Did you pump the fork and dampening rod to make sure oil was thru it? I pump the old fluid out the best I can and then have to pump new fluid in after filling it. That might change the oil level as well. I've never used the measured out method, just the 130mm from top and it works fine.

5wt seems pretty low. Stock is 10w. The last ones I did, I used 7wt.

Oh, and 1qt is plenty to do both forks from my experience. This is from doing 2 different VFR's, a Hawk GT, and 4 sets of 41mm forks on Superhawk's.

Well, I 'think' I am getting it now.   But I got all messy and now I can't be sure I've got the correct oil in both...so I am off to get some new, just to be certain.   A lot of messy work to go through to get it wrong...and the stuff that came out was pretty black with lots of metallic glitter in the  bottom...so I guess pumping some clean through and then changing that out again...that might even do some good....
  Thanks for the reply...Last bike I did was MY hawk, but that was years ago and I've forgotten how it went...

don hanson

[image: View Post]gnarly928, on 21 March 2012 - 01:37 PM, said:

When I put the specified amount...about 15.xx Oz of oil in, it leaves me about 70mm between the oil level and the top of the slider, without the spring or anything else in the fork...
Have you pumped the cartridge rod a couple of times to get all the air out of the fork?

Further work on changing my fork oil has left me with some major questions about what I found inside and what I should try to do.   So this should maybe be another thread, but I wanted to post while everything is fresh in my mind.   So here goes.

  My 2000 came to me with an Ohlins rear shock.  I don't know about the fork internals and the guy I got the bike from was not very knowledgable about this bike, he just used it to commute on the freeway in Portland mostly.  General mechanical condition indicates, as I've been going through the bike that at one time someone knew something, but I've found evidence of channel locks and crescent wrench work, too.

   The front end is my last mechanical task undone, and I've noticed poor handling and odd behavior (I think, I have never owned or ridden a VFR before..so this may be semi-normal)  The forks 'clunk' when the front wheel is unweighted.   It it not the steering head, that specs out.  Also, as I cross over from right to left or left to right, in a change of direction, the bike feels momentarily un-connected, right as it crosses upright.  And when I encounter anything on the road, like even a painted line, the wheel feels that, though I have ridden the bike pretty hard, just thinking "maybe these VFRs just have really crappy front ends, stock"

   So I dove into the forks today, thinking I would at least change the oil and inspect things inside, without removing the 'dampener rod?"...Please excuse me for maybe not using all the terms right from the manual...I think I'll get more across if I ask while things are really fresh in my mind, rather than going back and getting the exact term from the books...  Ok so heres what I am finding...It looks as if someone was in there, it has aftermarket springs, I am almost certain.  The springs are straight wound and have "08713-95/1541" etched on the top.   They are 300mm long when the Clymers I have says the length should be 382 for stock springs.  Now, I also found some thing wall steel spacers in the fork legs...two per leg on each end of these springs.   These are about 34mm in diameter and seem right, but they are all four different lengths...That doesn't seem at all correct...big differences...like 20mm.

   I kept each 'stack' in exactly the same order as I took the springs and stuff out to change the fluid.   I think I got that part right.  When I put it back together, now I think the whole inside assembly is not long enough...Maybe that is causing my 'top' clunk as the wheel 'sags' or is unloaded.  When I put the fork cap back onto the rod assembly, there is about 20mm where there is no load at all on the pre-load.   With everything back together but the fork leg in a vice, if I pull the leg up to full extension then push it back down, it goes down almost 45 mm until you can feel the preload adjuster contact the rod inside...that is not correct, is it?  

  I am thinking I need to make the spacers the correct length to have just a little tension as I start the treads of the fork cap with the leg at full extension.  Is this right?

  someone want to help me here, or direct me to a place where I can read about how to set this up properly?  It seems to me that my preload adjusters are useless right now...and it seems like when the front is in 'rebound'...there should still be some spring contact inside...

  Help.......I am kinda lost here...  The bike was rideable, not really awful before...but pretty weird feeling to me.
  Don Hanson

Don, In my experience, the black metallic oil in your forks is normal. I flushed mine out with ATF and let them drain overnight before assembly. I would seriously look at your fork springs. 82 mm difference in length is about 3 1/4 inches. That's a lot of dimension that must be taken up with a spacer that does not compress. It sounds to me like your forks are expanding beyond the compression of the springs. They should not do that. You have adjusters at the top of your forks that should be under compression all the time, even with the front wheel off the ground. Good aftermarket springs are available for not too much $. Compress the fork when you fill it, then expand it when you insert the spring and thread in the cap. You should have to compress the spring (with any spacers required) a little in order to start the threads on the cap. Back off the adjuster to make it easier. Good luck.

[image: View Post]jeffyjeff, on 22 March 2012 - 12:02 AM, said:

Don, In my experience, the black metallic oil in your forks is normal. I flushed mine out with ATF and let them drain overnight before assembly. I would seriously look at your fork springs. 82 mm difference in length is about 3 1/4 inches. That's a lot of dimension that must be taken up with a spacer that does not compress. It sounds to me like your forks are expanding beyond the compression of the springs. They should not do that. You have adjusters at the top of your forks that should be under compression all the time, even with the front wheel off the ground. Good aftermarket springs are available for not too much $. Compress the fork when you fill it, then expand it when you insert the spring and thread in the cap. You should have to compress the spring (with any spacers required) a little in order to start the threads on the cap. Back off the adjuster to make it easier. Good luck.

   That's what I was thinking, but I haven't been inside forks for quite a while.   Yes, you describe it better than I  did....my "forks are expanding beyond the compression of the spring".   And I don't have to "compress the spring ( I think my spacers are much too short from the last owner) a little to start the threads of the cap"....As I mentioned in my second post, there is a big 'unsprung movement' maybe ~40mm, before the preload adjuster even seems to make internal contact with anything...at least when I fully extend the fork leg with the slider in my vise and then re-compress it, it moves shorter about 40mm, then I hear and feel internal contact, and the resistance increases there.

  Maybe the guy who had this bike before me, the guy with the Visegrips and the wrong sized screwdrivers and the rattle can ....maybe he swapped the springs but just used some scrap he had laying around or re-used the stock spacers....I would think this was the case except.....all four thin wall steel spacers are a different length....but the two fork leg stacks ended up being equal lengths (at least)

   So I should make some spacers to just let the fork caps, with slight compressing, screw into the legs with the preload turn all the way out, right?    That could be the cause of the 'clunking' I feel when the front end unloads..
  Thanks,  Don Hanson

At this point, if i suspected the springs were not intended for the forks, i would not  try and make them work. Especially when you mention metal in the oil.

i would invest in making sure the forks have the proper vfr internal bits. New, upgraded or used...
To me it would be a peice of mind issue...

If you have an ohlins rear, why not upgrade the front while your in there, as already mentioned.

[image: View Post]gnarly928, on 21 March 2012 - 09:56 PM, said:

With everything back together but the fork leg in a vice, if I pull the leg up to full extension then push it back down, it goes down almost 45 mm until you can feel the preload adjuster contact the rod inside...that is not correct, is it?   You are right, that is not how it should be. When putting on the fork cap you allready should b compressing the spring a tiny bit.
I agree with kc5555, get springs (and spacers) that are made for your fork. The 300mm springs might be too short and start binding too soon.

Ok, let's sort you out.

You definitely have aftermarket springs, with a .95 rate. May I ask your weight? Also, see if you can locate a similar number on your Ohlins spring. This will let us determine if your spring rates match. If they do they may be too stiff for your weight, causing ill handling. If they are unmatched, this can also cause ill handling.

The rule of thumb for replacing fork springs is to measure the old spring + old spacer, subtract from that sum the length of the new spring, then cut the new spacer to the remainder. The spacer length can be tuned to suit desired preload. Sounds like this was not done properly by the person who installed the springs in your bike.

The black metallic substance in your oil is perfectly normal, this is the reason why frequent fork oil changes are recommended. It is a result of the springs running on the inside of the fork tubes.

If your oil was dirty, I highly recommend that you fully disassemble the forks and the valving and clean all the parts thoroughly.

Once you respond with your weight we can take this a bit further but for now you just need to get your spacers to the correct length.

I have multiple sets of aftermarket VFR springs at home, I dont know their length off the top of my head but I can check for you later. A bit shorter or longer won't matter, but if yours are too short they could bind under heavy compression.

Also, you are correct about having to push on the fork cap to reassemble - again it sounds like someone got your spacers wrong.

Lastly, with regard to oil, most are not created equally and as such one must reference the CSt rating to ensure viscosity. For everyday riders with cartridge forks I usually mix Honda's ss8 and ss10 to come up with a "blended 7.5wt" oil. Of course, everyone is a bit different so I end up adjusting shim stacks, oil height, and oil choice to suit an individual need and/or budget.

Hope that helps get you back on track.

[image: View Post]SEBSPEED, on 22 March 2012 - 07:12 AM, said:

Ok, let's sort you out.

You definitely have aftermarket springs, with a .95 rate. May I ask your weight? Also, see if you can locate a similar number on your Ohlins spring. This will let us determine if your spring rates match. If they do they may be too stiff for your weight, causing ill handling. If they are unmatched, this can also cause ill handling.

The rule of thumb for replacing fork springs is to measure the old spring + old spacer, subtract from that sum the length of the new spring, then cut the new spacer to the remainder. The spacer length can be tuned to suit desired preload. Sounds like this was not done properly by the person who installed the springs in your bike.

The black metallic substance in your oil is perfectly normal, this is the reason why frequent fork oil changes are recommended. It is a result of the springs running on the inside of the fork tubes.

If your oil was dirty, I highly recommend that you fully disassemble the forks and the valving and clean all the parts thoroughly.

Once you respond with your weight we can take this a bit further but for now you just need to get your spacers to the correct length.

I have multiple sets of aftermarket VFR springs at home, I dont know their length off the top of my head but I can check for you later. A bit shorter or longer won't matter, but if yours are too short they could bind under heavy compression.

Also, you are correct about having to push on the fork cap to reassemble - again it sounds like someone got your spacers wrong.

Lastly, with regard to oil, most are not created equally and as such one must reference the CSt rating to ensure viscosity. For everyday riders with cartridge forks I usually mix Honda's ss8 and ss10 to come up with a "blended 7.5wt" oil. Of course, everyone is a bit different so I end up adjusting shim stacks, oil height, and oil choice to suit an individual need and/or budget.

Hope that helps get you back on track.

   Thanks everyone.

  I spent a few hour last evening, reading all the threads I could find on here about forks, swaps, cartridges, etc. so I have a better idea now about what I seem to have going on with these forks.  I'd read before about oils and spring rates so this first fork oil change is mainly to see what I have, to see if I can do something for the front end until I can really revise it properly.  I plan on modding the forks in a short time and de-linking the brakes but I'm short of cash right now, so I am working with what I have.  

I have put maybe 500 conservative but sporty riding miles on this bike so far, and I suspected something wasn't quite right at the forks.  I've been working through this 'new to me' bike, checking the 'normal' and critical things first, then going deeper as I check things off my list.   I seem to have discovered that these fork internals have been somewhat botched, with improper spring length/spacers, I guess.

   I think at my weight, 175lbs/200lbs with gear on, the .95 weight springs will work (for preliminary,  baseline,  riding) but I am reading the spacers need to be corrected?   I couldn't see any spring rate noted on the rear Ohlins spring (yellow) but I set it up with the remote preload adjuster to get 30mm of sag with it 7 turns out from full hard.  I know, the suspension works as a unit, so that rear sag won't actually be correct till I get the forks closer.  The rear suspension  seems pretty good so far.   The forks, however, feel wrong, as I've said.  

   I am going with the Pro Honda SS-7 (5w) oil this time.   My first re-assembly I did with this oil, then I re-drained after I realized that something wasn't quite right.  So they've been flushed and re-filled with this oil.  My goal for now is to just get the forks functioning properly.  Once I get them in the ballpark, I'll be able to do some baseline riding to see what I want to try to improve on...but for now, I need to correct the spring/spacer length, right?

   Could I begin with simply using the shop manual specified spring length to cut some new spacers?  The Clymers I have says 382mm>  free length.  With straight-rate springs this will likely give me too little sag at the front, but it should be a start,  correct?  Could I simply put my current .90 kg springs(as marked) back into the fork leg and measure the distance to the seat for the dampner rod inside the fork cap, with the preload adjuster in the middle, then cut some spacers to match the needed length so that when I fully extend the forks and start the fork caps I am compressing the springs just a little?   Right now, with the spacers I found in there from the previous owner, I have what I'll call slack.  With the slider in a vise, the spring, spacers and fork cap assembled inside, I measure 54mm between the top of the fork leg and the lip on the fork cap where it should be when threaded in when the fork is 'relaxed'....I have to 'lift' the fork leg up on the dampner rod to reach the threads on the fork cap and start it screwing together....It's my understanding (now) that I should be needing to depress the fork cap slightly against the spring tension to start those threads...    As I mentioned in my previous posts, the spacers inside the fork legs are all slightly different lengths by as much a 20mm...there are spacers under and over each spring, cut from thin wall steel.  These seem to fit properly in the forks, to match the diameter and not bind or anything.  They are 34mm OD.  The springs are 300mm long and didn't 'bottom' out or feel 'coil-bound' during my limited riding so far.

  If I cut some spacers to give me just a little tension as I start the fork caps into the fork legs....put  SS-7(5w) Pro Honda fork oil in there with 125 mm of air space...you think I'll have done this 'more right' than I found it?

   During my limited riding so far, I've felt a clunking as the fork extends.  I've felt 'vagueness' as I cross over from lean to lean.  During cornering it feels ok...nothing particularly alarming, other than at the top of the suspension travel.  I have been pretty 'timid' with the corners until I get this sorted a little more....  I've not had any problems with tire/engine clearance.  The forks *were* up in the triples at 51mm from the bottom of the cap to the top of the triple...I'll be setting them at 47mm to resume my 'sorting out' of the front end when I get the forks back together properly.

  am I on the right track here?  Any suggestions?  (I can't afford new springs right now...I want to 'get a feel' for what I need using what I have for a baseline for a little while before I start $pending )

  Thanks,  Don Hanson

Don, I don't think I can simply my previous post any further.

If you don't have stock springs you can assume the free length per the manual and get the spacer number by posting here for help with that. I'm not that I have one. I should, but unusually chuck them when upgrading. Anything else is just a guess.

Do that, and go from there. The bike will be vastly different by the sounds of things.

The number for the rear should be printed on one of the coils. You may have to do some cleaning to find it.

Ok, I have everything apart again and I am still not clear on it.  I think I may know what I don't know, now.   (grin)

  Could someone clarify....am I looking for the total length of 382.7 mm, including the spacer(s) before I put the keeper on and then screw the fork cap onto the rod and then compress the cap on the spring and close up the fork?   That looks like what the previous owner tried to do...I think.

or am I supposed to start from that free spring length (as stated in the Clymers I have) and then *add* spacers to make the over all internal springing "stack"  need just a little compressing to start the fork caps into the fork leg when everything is fully extended?

   I will post a few pics I just snapped.

  Don Hanson

From what I remember, 382 is just the spring length. You then need spacers to take up the gap. When screwing on the cap, I think you should have 15-20 mm of pre-load (compression of the spring). If the cap screws on without having to compress the spring any, you need longer spacers.

[IMG]http://i1088.photobu...28/100_1416.jpg[/img]

[image: Posted Image]

trying to load some pics here of the forks I am working on

[image: View Post]gnarly928, on 22 March 2012 - 01:47 PM, said:

[IMG]http://i1088.photobu...28/100_1416.jpg[/img]

[image: Posted Image]

trying to load some pics here of the forks I am working on

  Wow, finally got it.  This is what I have with the fork slider captured, fully compressed and relaxed,  upright in my vise and all the innards assembled.  That is the way it sits.  I can take the fork leg in hand and connect the fork cap with no resistance.  I can then take the fork and extend it further, leaving the spring 'slack' for about 50 more mm.

Ok, I have about 40mm of gap, with the fork sitting in my vice and the cap screwed onto the rod, but with the leg of the fork settled to where it sits...So to get the cap to thread, I must grab the fork leg and extend it upwards, then thread in the cap.   I think I need longer spacers, so hopefully I have this right now, finally.

The stock spring is 382mm and with it comes a spacer that is about 10cm so the spring and spacer combined need to be roughly 48cm.

[image: Posted Image]
service manual pic of stock spacer

[image: View Post]SEBSPEED, on 22 March 2012 - 07:12 AM, said:

The rule of thumb for replacing fork springs is to measure the old spring + old spacer, subtract from that sum the length of the new spring, then cut the new spacer to the remainder. The spacer length can be tuned to suit desired preload. Sounds like this was not done properly by the person who installed the springs in your bike.
^^^^^^^^^^^^^^^^^^^^^ This!

All Right!  Success!  I made some new collars, or spacers.  The collars or spacers that were in there were about 40mm too short.   I used some thick walled white PVC and got some remarkable results.

  Now the forks actually seem to work properly.   With them set up at 47mm above the triple clamp and with 35mm of front sag, the bike seems to want to tip in a bit too much, on my very short test ride this evening, but the suspension seems about 200% better than before...no clunking, not harsh initially, then loose on rebound...More like a 'real' fork.

  Thanks for all your patience putting up with my bazillion lame posts..Now I can actually see results when I change a setting with the front end, and it is behaving like a normal suspension...so I have a base-line to fine tune from, to get an idea of exactly what modifications I will eventually want to do.

  It is a bit more complex dialing in a different type and specific model bike you  have never had experience with...especially when someone else may have done modifications, some poorly....Like the forks here.  When you go to the service manual and work from the specs but a mod has been done you aren't aware of, things get confused.

I am just glad I didn't have a "tank-slapper" episode at speed, or have the front wheel drop off while canyon riding...   This front fork inspection and revision, that is the last part of the bike I have not taken apart and re-assembled according to the books, so I now feel pretty good about this now nice VFR.   Next major task will be my Tempest Gray paint job after I mount some frame sliders..

  Thanks again, all
  Don Hanson

If you are curious and haven't found out yet, your part number indicates the springs are .95kg/mm Ohlins for a 05-06 ZX6R

[image: View Post]NakedViffer, on 22 March 2012 - 09:42 PM, said:

If you are curious and haven't found out yet, your part number indicates the springs are .95kg/mm Ohlins for a 05-06 ZX6R

  Ah,  I was wondering where this guy came up with the springs.   He also mentioned something about a ZX electrical component..maybe in the charging system.   That is another place I will soon be 'visiting' on this bike.   I did find a used but good R & R that I got for cheap and will stash under the saddle if I go on a longer trip somewhere with the bike.

   When I bought the bike, I was under the impression that the seller didn't do any of the work on it himself...he mentioned something about getting it from 'his cousin'....Every time I go into this, I find something that isn't stock.  He had the gearing really high...two down at the rear and one up at the countershaft...it was like 3rd gear was freeway speeds....

  I wonder if the whole inside of the forks are Ohlins?  Would that not be a sweet surprise....But there is no rebound adjustment...so

  Thanks for the info.  Don Hanson

Possible, but not probable. Being that the forks come with no rebound/compression stock. Adding aftermarket internals wouldn't change that, you'd have to swap to forks with external adjustment. So you may have other aftermarket parts in there.

[image: View Post]gnarly928, on 22 March 2012 - 07:48 PM, said:

and with 35mm of front sag, the bike seems to want to tip in a bit too much,
That is 35mm. with you on the bike, right?
Glad you got it sorted :fing02:

You might want to go over to my site and check out the How To section on setting fork spring preload. What you DON'T want to do is make the overall stack height the same as stock. The stock setup has a bunch of extra preload added to make up for the excessively soft springs. What you need is approximately 16mm of initial preload.

Go through the steps outlined on my site and I think you should be able to get it sorted out just fine.

Hint: if your springs are 300mm long the space total length should be around 120mm.

[image: View Post]JamieDaugherty, on 23 March 2012 - 07:14 AM, said:

You might want to go over to my site and check out the How To section on setting fork spring preload. What you DON'T want to do is make the overall stack height the same as stock. The stock setup has a bunch of extra preload added to make up for the excessively soft springs. What you need is approximately 16mm of initial preload.

Go through the steps outlined on my site and I think you should be able to get it sorted out just fine.

Hint: if your springs are 300mm long the space total length should be around 120mm.

  Ah, the Master.....

  Thanks..I got to 35mm of sag with the preload adjuster almost all the way down.  I need my spacers just a bit longer...I sized them to take no force on the spring to start the threads with the preload set in the middle of it's range.

It's pretty amazing, the difference between fully functional forks and the way these were before.  I was going to add about 10mm to my spacers to bring my preload adjusters up to what the manual say...9mm.

  Now, with the forks working more normally I can go back to the rear, also and begin to adjust and dial in the whole package.

  Don Hanson

Don,
Will sizing your spacers that way give you the 16mm preload you are looking for?   Jeff  J

[image: View Post]jeffyjeff, on 24 March 2012 - 09:18 PM, said:

Don,
Will sizing your spacers that way give you the 16mm preload you are looking for?   Jeff  J

   I put 11mm more onto the spacers.   That, with my preload adjusters out now about 10mm from the top of the fork cap nut, that gives me 35mm of sag at the front...  

   I just today did about 200 miles with an R-1, a Daytona 675 and some other sporty bikes, riding every twisty road around Hood River, Oregon on our Saturday morning coffee ride and the bike felt very good, better than I anticipated.  Couple of times on rough sections the front end steeped out, but it was only slightly.   I have no idea of how old that tire is, it looks ok, but.. A Shinko (?) on the rear...  About 3/8" of chicken strip on that one, with snow on the roadsides, so cold pavement...

  Anyway, for my first  real spirited ride on this bike, I was pleased.   The R-1 guy with the full Ohlins, trick everything and track leathers...he was a bit surprised to find me glued to his wheel, or leading and leaving on some roads I knew better than him.   I imagine with some good tires and a bit more seat time on this bike,  it will be plenty adequate for canyon carving..it already is.   And one more thing...after that 150-200 miles, nothing hurt...no sore wrists, no tight back, no cramped thighs...I actually chose to add an extra 50 mile twisty road when everyone else went for lunch and then home...   I will say, the Daytona with the underseat Jardine exhaust...that was beautiful sounding..And the R-1 also had dual carbon underseat cans....

  Fun stuff.  Don Hanson

More on my suspension dial in...after getting the forks as right as I wanted for sag and ride height, I went and re-checked the rear...The rear tire was about 2 inches above the floor when on the  center stand....(no wonder I was having difficulty getting it onto the stand)  My sag was almost 70mm, so obviously the spring is soft, and maybe it is the wrong shock altogether...since the fork springs came from another bike...
  I didn't go so far as to get the whole shock out and off the bike to read all the numbers and cross check the spring.   For now, since the rear seems to behave pretty well anyhow, I shimmed the rear top shock mount and gained 20mm of ride height at the back, then set the remote adjustable ride height setting almost full hard...that brings my sag numbers down...for now, best I wanted to deal with.  The shock link plates were quite dry in the bearings and there was some gravel grinding around near one of the bushings.  Cleaned and greased, should make things smoother.
   I haven't had a test session yet.  Kinda fun, dialing in a "new" bike...

Any way you could post some pictures?

Its beginning to sound like the bike was lowered and you're chasing your tail trying to band aid the thing.