Fork oil level question

[Tom]

Need some help.....

After reading several articles posted at FJRTech, I got it in my head that the fork oil level was to be 100mm. Then I found an FJR shop manual posted on-line and it listed the level as 79mm.

I have a 2003 US model, so can someone please clear up my confusion?

Thanks!

Tom

 

[SkooterG]

My 04 shop manual (the real thing) says 100mm of airspace with springs out.

 

[ionbeam]

I think we need to wait for someone with an '03 FSM or actual experience...

From two different FSMs:

Gen I – 2004

Quantity (each front fork leg) 22.3 US oz

Fork oil level (from the top of the inner tube, with the inner tube fully compressed, and without the fork spring) 100 mm (3.94 in.)

Gen II - 2006

Quantity (each front fork leg) 23.53 US oz

Fork oil level (from the top of the inner tube, with the inner tube fully compressed, and without the fork spring) 92 mm (3.62 in.)

 

[exskibum]

I'd rely on FJRTech -- here's their fork oil change instructions for '03 to '05:

https://www.fjrtech.com/getdbitem.cfm?item=47

Look at item 17 -- says 100mm (just as you recalled).

Like SkooterG and ionbeam, I also have Yamaha's paper service manual for my '05 (should be same for '03 to '05 on this issue). Under chassis specs on p. 2-13, it says 100mm (3.94 in) "from the top of the inner tube, with the inner tube fully compressed, and without the fork spring", also noting that this is 670 cm3 of oil for each fork leg. On p. 4-68 of that same manual, in addressing the filling of the fork leg, it only refers to the 670 cm3 volume, with no mention of the level. When I've done mine (an '05), I've just relied upon the FJR Tech article I cited (and you probably read) -- clearer instructions in one place.

 

[yamaholic]

Gents, I authored the article and found that the 79mm figure is the European version measurement for the 2002 Euro model. 100mm is Americas version 2003 model (which supposedly was the same bike, but since these measurements were different, who knew what else was).

Tom, that online manual is 'prolly for Europe, no?

I confirmed the 100mm figure for the 03 via a member that had the FSM at the time of writing the article. Looks like 03-05 are the same, 06 different again (thanks, Ionbeam). At the time of writing, it would be impossible to confirm all worldwide measurements over the model years, so sorry if there was doubt.

Guess we should update the article...

 

[dcarver]

I've often wondered..

Is that measurement with forks vertical, e.g. perpendicular to the ground or in the triple tree?

 

[gainsi]

Guys, this won't give you a definitive answer, but I've done this on my 2001 Oceania FJR-1300N. I drained out the old oil (which was very dark & dirty), & then flushed the forks with a cheap fork oil, gently raising & lowering the fork tube to work the oil. The forks were removed from the bike to do this of course. I then drained out as much of the flushing oil as possible by suspending the fork over an oil tray & giving it time to drain. Again, raise & lower the fork tube to help with the draining.

I then added the better quality oil, worked the fork tube again to get rid of bubbles, & then measured the gap from the top of the fork tube to the oil level with the spring still out of the fork tube. I used the 100mm gap & it worked fine for me. I wouldn't get too anal about how much oil you've added as it depends on how well drained it was in the first place. Also, hold the fork vertical to do the measurement (like in a wood vice).

I had seen the 79mm figure mentioned too, but 100mm works fine in my forks. Good luck.

 

[Zorlac]

GP suspension recommended 120mm of 5w synthetic fork oil after they upgraded my front forks in last year's group buy.

 

[Tom]

Thanks folks for the speedy replies and information.

And in case you're curious, I'm just doing a fluid change, new seals, and installing a set of 2004 fork springs in my 2003 forks. I would love to have been in on the group buy action, but being this close to Christmas, saving for a trip to see my parents (and sadly, possibly the last Christmas my Mom will see), and various other money sucking priorities has made the GB an impossibility. Oh well.......

And FWIW - I'd like to take this moment to give a collective thanks to those of you who've contributed to this forum in either a technical capacity or in the relm of humor. As you can see by my post count, I don't contribute much, however I visit this forum daily since I joined in 2006.

I own a 2003 that I purchased in December 2003 as part of the first priority delivery program. My decision to buy the FJR was after seeing Eddie Lawson do a rolling burnout down pit lane at Daytona Speedway on an FJR in 2003. Much to the embarassment of my friends as we sat in the stands watching Eddie, I jumped to my feet and hollered, "OH HELL YEAH - THAT'S MY NEXT F*CKING MOTORCYCLE!!!" The FJR soon occupied the garage with my ZX9R and the hellaciously fast H*nda NS50. Don't laugh - I could damn near carry the same cornering speed on the NS50 as I could on any other bike in the North Georgia mountains. Ok.....so I had to be going downhill with the wind behind me. Technicalities, technicalities.............

Again - my very long overdue thanks for the info I've gotten from this forum.

Tom

 

[teerex51]

I've often wondered..
Is that measurement with forks vertical, e.g. perpendicular to the ground or in the triple tree?

Like Gainsi pointed out, vertical.

Stef

 

[exskibum]

Gents, I authored the article and found that the 79mm figure is the European version measurement for the 2002 Euro model. 100mm is Americas version 2003 model (which supposedly was the same bike, but since these measurements were different, who knew what else was).
Tom, that online manual is 'prolly for Europe, no?

I confirmed the 100mm figure for the 03 via a member that had the FSM at the time of writing the article. Looks like 03-05 are the same, 06 different again (thanks, Ionbeam). At the time of writing, it would be impossible to confirm all worldwide measurements over the model years, so sorry if there was doubt.

Guess we should update the article...

I wonder what the level would be with exactly the prescribed 670 cm3 of fork oil poured in after doing a thorough job of flushing and draining. I'll be doing this operation this winter and will try to remember to pour in exactly 670 cm3 and measure it.

BTW, merci for writing and posting the fjrtech article, Mssr. Holic.

 

[hppants]

Enjoyed reading this thread. I just changed my fork seals this past weekend, but have not yet filled with new oil. I had one leaking, and one not leaking. I know for a fact that the oil in the forks was the factory oil. I have been researching heavily on this forum trying to get the correct amount of fork oil

I have an "FYI" and a question:

1. FYI - for the non-leaking fork, I took EXTREME care to remove and measure all of the oil. Using a 500 ml graduated cylinder (pretty accurate), I was able to remove 653 cc of fork oil from my non-leaking fork. Knowing that there was a small residue of oil on my spring, piston, and lower fork leg, and coupling this with the fact that over 6 years, a small amount of residue evaporated on the slider, the 670 cc figure seems very compelling to me. Your thoughts?

2. Question - I can understand how to measure the fork oil without the spring in it. I've done fork seals on a few other bikes, and they all spec'd this way. However, for the 2005 FJR, after that oil is poured and measured, how can I re-install the spring and tighten the spring/rod/piston assembly without removing it from the slider/lower leg assy? Of course, if I do that, by removing the lower bolt, all of the oil will fall out.

FWIW - I'm trying desperately to get a FSM, but alas, these seem to be made from "Unobtainium".

 

[ionbeam]

0. Read this from FJR1300.info

1. The Gen I manual specifies 6703 cm (22.3 US fl oz) and I'll add that calculates to roughly 659.489719 milliliters In theory that volume of fluid should achieve a depth that is 100mm down from the top of the tube.

2. Some text excerpted from the FSM ---->

6. Install:

• oil seal clip 1

NOTE: Adjust the oil seal clip so that it fits into the groove of the outer tube.

 

7. Install:

• dust seal 1 (with the fork seal driver) New

 

8. Fully compress the front fork leg.

 

9. Fill:

• front fork leg

(with the specified amount of the recommended fork oil)

CAUTION:

• Be sure to use the recommended fork oil. Other oils may have an adverse effect on front fork performance.

• When disassembling and assembling the front fork leg, do not allow any foreign material to enter the front fork.

 

10.After filling the front fork leg, slowly stroke the damper rod 1 up and down (at least ten times) to distribute the fork oil.

NOTE:

Be sure to stroke the damper rod slowly because the fork oil may spurt out.

 

11.Slowly stroke the inner tube 1 up and

down.

 

12.Before measuring the fork oil level, wait ten minutes until the oil has settled and the air bubbles have dispersed.

NOTE:

Be sure to bleed the front fork leg of any residual air.

 

13.Measure:

• front fork leg oil level a Out of specification → Correct.

Front fork leg oil level (from the top of the inner tube, with the inner tube fully compressed, and without the spring) 100 mm (3.94 in)

14.Install:

• nut 1

• damper adjusting rod 2

• cap bolt 3

 

a. Install the nut 1 and finger tighten it.

b. Install the damper adjusting rod 2.

c. Install the cap bolt 3 and finger tighten it.

WARNING Always use a new cap bolt O-ring.

d. Hold the cap bolt and tighten the nut 1 to specification. Nut 25 Nm (2.5 m · kg, 18 ft · lb)

 

15.Install:

• cap bolt (to the outer tube)

NOTE:

• Before installing the cap bolt, lubricate its Oring with grease.

• Temporarily tighten the cap bolt.

 

[MCRIDER007]

GP suspension recommended 120mm of 5w synthetic fork oil after they upgraded my front forks in last year's group buy.

Oil height is used to control the volume of air that is left in the forks after the springs are installed. That volume of air is then used to add resistance at the end of the stroke to prevent bottoming. Too much air will make it easier to bottom, too little air will reduce the fork travel that is actually available. The "correct" oil height is going to be determined by the rider's weight, how hard they brake, the spring's resistance, and the spring's displacement of oil/air inside the fork tube. GP suspension uses heavier springs that displace more area inside the fork tubes, therefore they recommend more oil height when the springs are out of the forks.

The recommended oil height is just a starting point for the springs that were installed in that model and a average rider. If you are bottoming under hard braking then you should add oil, if you aren't using most of your travel under hard braking then you should reduce the amount of oil.

 

[RossKean]

...

1. The Gen I manual specifies 6703 cm (22.3 US fl oz) and I'll add that calculates to roughly 659.489719 milliliters In theory that volume of fluid should achieve a depth that is 100mm down from the top of the tube.

...

How do they get 22.3 fl oz from 670 cm3?

EXACT measurement is not as important as having both the same.

 

[ionbeam]

How do they get 22.3 fl oz from 670 cm3?

EXACT measurement is not as important as having both the same.

They get that volume by being wrong. Even rounding readings can't explain it. It's the same way the FSM tells you to read a relay coil to be 100Ω when there is an internal diode in series with the coil. Can't be done.

The Gen II FSM says 696.0 cm3; 23.53 US oz; Level 92mm (3.62 in) All units are accurate with rounding.

 

[hppants]

Aw - shoot, I've got something wrong. My dampening rod nut just spins - I can't see how to get it apart. I think it spins with the spacer above the spring washer. I've got to pull it back down and look closer. Another thing I'm puzzled by is my lower bolt doesn't spin the lower piston assy like it did on disassembly. I can tighten and torque with a hand rachet - even with the top cap removed. I wasn not expecting that.

I've got something jammed up - back apart it goes. I'll take some pictures