Fork oil replacement

[nortstudio]

I have read a bunch on here and the archives about redoing the forks. I plan on getting new seals and springs in the near future, but I will have to wait a bit for that.

I'm wondering if I can replace the fork oil with the forks on the bike - or if off the bike, without messing up the seals etc. there is no leaking on the outside of the forks, but the diving is pretty bad, so I fear the oil is a smelly, watered down mess.

I have the drain screws, can I just pump it out, and refill? If so, what level would I use, since the normal procedure would be off the bike.

Thanks

[yamaha_george]

I have read a bunch on here and the archives about redoing the forks. I plan on getting new seals and springs in the near future, but I will have to wait a bit for that.

I'm wondering if I can replace the fork oil with the forks on the bike - or if off the bike, without messing up the seals etc. there is no leaking on the outside of the forks, but the diving is pretty bad, so I fear the oil is a smelly, watered down mess.

I have the drain screws, can I just pump it out, and refill? If so, what level would I use, since the normal procedure would be off the bike.

Thanks

Hi,
changing the oil in the forks depends on your forks. Yamaha changed the design slightly over the years .
Very early models had a tiny screw at the axle end that capped a drain hole in the lower casting IF you have this type you remove the wheel only (so the forks can be "pumped" to remove the old oil & flushing liquid. ) You will have to support the bike in a steering stem type paddock stand OR tie it to the rafters in the garage or barn to keep the bike from falling over.

If you have the non-drain type forks the forks will HAVE to be removed.

I did a fairly comprehensive write up on this, along with how to install PD valves (emulators in America) @ :=

http://www.saltmine.org.uk/fzr/fork.html

This write up also tells you how to make your own fork tools !!

[taggy]

it's propabaly advisable to drop the forks out and leave them inverted for a day or so to allow all the old oil out.

[nortstudio]

Thanks guys. George, I read you write up 2 days ago, but obviously you were going full tilt with the emulators etc. that would be great to do down the road - but fresh oil would have to be better than what I'm experiencing now.

I do have the drain screws, and some hefty rafters/joists I could support it from in the garage (yay 19th century NYC builds!). I might give this a shot. Any idea of how to measure the oil like this? X" from top etc.

Appreciate the help.

[yamaha_george]

Thanks guys. George, I read you write up 2 days ago, but obviously you were going full tilt with the emulators etc. that would be great to do down the road - but fresh oil would have to be better than what I'm experiencing now.

I do have the drain screws, and some hefty rafters/joists I could support it from in the garage (yay 19th century NYC builds!). I might give this a shot. Any idea of how to measure the oil like this? X" from top etc.

Appreciate the help.

+
NS,
well at least you have rafters to hang the bike :-] so you are off to a good start.
Did you read the how-to on suspension tuning (Jim & I wrote that L o n g ago) but it will give you a .clue as to how to pick an oil weight and how much oil for the 600 in standard form should be listed in the FZR handbook (not near my library of bike books so cannot look it up for you this time sorry.) There is also aset of notes on what Jim and I used on our bikes NOTE this is for our body weight and in Jim's case his bike , mine is for an FZR600 '92 model

[nortstudio]

Yep, I read that article when I first got the bike (and saved it to my phone for reference at the garage) - but I will go back to it for a refresher course. I just knew that usually these bikes are done using a measurement (so many inches from the top - fully compressed...etc). But I am sure that going by the volume amount will be a vast improvement.

Hope you are feeling better, and thanks for all the info.

Scott

[pefrey]

The easiest way to set the oil level is to buy one of those "flavor injector" syringes and cut the barrel off just above the cross drilled holes. Overfill the forks with your new oil, insert the syringe 110mm into the tube, and suck out the oil.

[nortstudio]

Thanks pefrey. Just to clarify, the 110mm is with the forks not depressed, and still in the triples? I don't have my manual in front of me at the moment - and I'm taking notes from this thread!

Appreciate all the help.

[kilika2]

This is in the wright up that George has in the wiki.


Hold the fork upright and with it fully compressed and no collar or spring installed fill it with fork oil to 3.98 inches from the top of the fork through the cap bolt opening. Be sure to fully extend and compress the fork a few times do distribute the oil. There are many different types of oil people have used. Automatic transmission fluid, engine oil, and different weights of fork oil have been used.

It's what I did.

Chris.

[nortstudio]

Yep, I have all that. I'm trying to determine if it's possible to do this without taking the front end apart - just put some fresh oil in it for now, until I get all the parts needed for a fork total rebuild.

if its not possible to do it on the bike, then my question would be, can I remove the forks, do all of the fluid swap, without damaging the seals etc?

George's write up is clearly for doing it the correct, thorough way. I'm looking to get some (any) oil in there for the time being.

[Nik]

Yep, I have all that. I'm trying to determine if it's possible to do this without taking the front end apart - just put some fresh oil in it for now, until I get all the parts needed for a fork total rebuild.

if its not possible to do it on the bike, then my question would be, can I remove the forks, do all of the fluid swap, without damaging the seals etc?

George's write up is clearly for doing it the correct, thorough way. I'm looking to get some (any) oil in there for the time being.

NS,
You can do this with the forks in the clamps (since you have the drain hole in the lowers type forks) Y-G did say that you will have to take the wheel off as that will aid in the pumping out the crap oil & flushing to give the internals a clean out Yeh Y-G does that bit extra at that point as he would hate to put fresh oil ontop of any old crud left in the fork.
Fork oil level is with no spring inside and fully compressed and the 110mm sounds familiar, Y-G & I (I provided the drinks) did this on my bike last summer when he was over here. Y_G did use a Huge vetenarians syringe (turkey baster) to set the levels spot on in both forks.

Since you are not putting emulators (sorry Y_G PD Valves) there is no need to disassemble the fork tubes from the castings and therefore no need to disturbe the fork seals so you are safe there.


I heard today Y-G was seen by a fresh team of Spine specialists yesterday and they are starting a fresh approach to his problem. You will be pleased to know he is out of hospital for now at least and not due back in till January for the final decision meeting with the new surgeon. Camala and his two girls are glad to have him home again (something they may regret LoL) but Knowing Camala she will not let him to much slack and letting him "over doing it" which being err shall we say stubbon he is want to do.

[nortstudio]

Thanks Nik. I will be following the full procedure one time/finances permit. But until then, I figure it's best to know I have at least some oil in there.

I will certainly have the wheel off, and maybe it's best to just have the forks off too. I just know that sometime soon I will have new seals and springs going in there - so I was looking to avoid the full tear-down. Always looking for the easy way out - when I KNOW that it never ends up being the easier/better way

Appreciate the help. Hopefully this oil can at least improve it some until I get dig in for a real fix.

Scott

[pefrey]

I know at least one person used a wet-vac with a smaller diameter hose taped on to suck out their old oil.

Either which way, you will have to unload the front suspension to take the fork caps off (lift by the frame or the triple tree) or the spring will shoot out with some force and you will gush old oil all over the place. I doubt you will be able to get the springs back in until you unload the front suspension.