Front Fork Oil

chapindad · May 19, 2011, 03:13:21 PM

How do check the oil? I think mine are good but honestly I have no idea.

Thanks

John

fj1250 · May 19, 2011, 04:59:23 PM

If your going to check it, just change it!

MC

andyb · May 19, 2011, 05:01:45 PM

+1

To check it, you either drain some from the bottom (and then you're low, so you need to add more anyhow), or you pull the caps from the top and see what you've got (and that's the same thing that's required to change it).

If you haven't changed it in the past two years, go ahead and change it.

markmartin · May 19, 2011, 11:17:00 PM

As said, I think it'll be easier to change it than check it. It'll cost you 1 quart of fork oil.

I think you have an '89??..

The easiest /quickest way I know how to change the fork oil is:

*Put the bike on the center stand.
*Remove the chin fairing.
*Support the bike under the frame so that your front wheel is off the ground.
*Loosen the very top triple clamp bolts on the forks.
*Loosen the handlebar screws and slide the bars off the fork tubes and tie off .(tie together- try to keep your master cylinders upright as much as possible)
*Unscrew the top fork cap with a 27mm hex driver. How to make one is here:http://www.fjowners.com/index.php?topic=671.0 Do this carefully, the cap is under pressure from the fork spring - push down on the cap and wrench as the cap is coming out of the fork .
*remove the fork drain screw at the bottom (side) of the fork slider and drain the fluid.
*reinstall the drain screw.
*remove the cap / rod assemblies and springs from the fork tubes.
*fill the fork tube to about 130mm (?)from the top of the tube to the fluid--this is measured with the forks fully compressed. Cycle the forks up and down several times as you fill the tubes with fork oil, to distribute the oil into the damper rods.
*reinstall the springs.
*reinstall the cap/rod assembly and tighten.
*re tighten the top triple clamp bolt.
*reinstall the handlebars

Note; not disassembling the fork and cleaning the sliders out with solvent will leave a wee bit of a scuzzy slurry of fluid at the bottom of the fork slider. Still, you'll have 99% new fluid which has to be better than the old completely scuzzy fluid.

carsick · May 19, 2011, 11:53:27 PM

Quote from: markmartin on May 19, 2011, 11:17:00 PM
*Remove the chin fairing.
......
*reinstall the springs.
*reinstall the cap/rod assembly and tighten.
*re tighten the top triple clamp bolt.
*reinstall the handlebars

Mark,
Very thorough procedure. Curious though, why remove the chin fairing? And even moreso, why not reinstall it? Is this to keep it safe forever? Because if you're not using yours, someone else could.

Pat Conlon · May 20, 2011, 01:07:40 AM

It's hard to put 2 jack stands under the frame rails with the chin fairing in the way.....

ribbert · May 20, 2011, 05:21:59 AM

Put a bottle jack on the lug in front of the sump drain plug with the chin fairing in place.

markmartin · May 20, 2011, 07:04:35 AM

Quote from: carsick on May 19, 2011, 11:53:27 PM

..., why not reinstall it? Is this to keep it safe forever? Because if you're not using yours, someone else could.

You're on to me. I was trying to create a glut in the '89 chin fairing market in order to get a good deal should I want to replace my leaky clutch slave disfigured scoop.

Quote from: ribbert on May 20, 2011, 05:21:59 AM
Put a bottle jack on the lug in front of the sump drain plug with the chin fairing in place.

Yeah, I'm getting too old to tempt fate. I'm sure it works, but I can't get over the vision of a bottle jack sticking up through my motor. 'Just can't bring myself to do it.

Arnie · May 20, 2011, 09:57:10 AM

After you've removed the cap/rod assemblies, and after you've removed the springs and the itty-bitty "drain" screws.....
Work the fork legs up and down to get most of the old, gloppy, fork oil out. If its more than a year old, it'll probably be like treacle.

NOTE: It really is better to remove the whole fork leg and turn it upside down to drain.

Then replace the drain screws, and refill with oil as markmartin has said.

Cheers,
Arnie

chapindad · May 20, 2011, 10:00:43 AM

Sounds like I have found my Memorial Weekend project. I have new bearings coming in for the front wheel anyhow so I will just redo all this at the same time. Should I get a seal kit while I am at it?

markmartin · May 20, 2011, 11:24:04 AM

Quote from: chapindad on May 20, 2011, 10:00:43 AM
Sounds like I have found my Memorial Weekend project. I have new bearings coming in for the front wheel anyhow so I will just redo all this at the same time. Should I get a seal kit while I am at it?

I think this is the definition of 'scope creep'. Well, you'll have the front wheel off anyway, and if your opening up the top of the forks, you're about half way through a fork rebuild , so if you can afford the parts, I'd do it. However, as was recommended to me, if your going to change the oil seals, change the bushings while your at it. It seems that changing the seals without changing the bushings sometimes leads to the seals leaking way prematurely. And new bushings can only make your forks work better(more scope creep, but what the hell).

This write up http://www.fjowners.com/index.php?topic=1911.0 will help show you what's involved in a fork rebuild, minus cutting the rods and installing emulators. Unless of course, while you've got the forks apart.....

Have fun.

markmartin · May 20, 2011, 12:35:01 PM

btw, Randy - RPM can have all these parts to you correctly, quickly and probably at the best price.

http://www.rpmracingca.com/

RichBaker · May 20, 2011, 06:55:59 PM

Quote from: ribbert on May 20, 2011, 05:21:59 AM
Put a bottle jack on the lug in front of the sump drain plug with the chin fairing in place.

That's what I did for years, until I got a fork stand.....

fb747 · May 23, 2011, 12:21:49 AM

I think this is the definition of 'scope creep'. Well, you'll have the front wheel off anyway, and if your opening up the top of the forks, you're about half way through a fork rebuild , so if you can afford the parts, I'd do it. However, as was recommended to me, if your going to change the oil seals, change the bushings while your at it. It seems that changing the seals without changing the bushings sometimes leads to the seals leaking way prematurely. And new bushings can only make your forks work better(more scope creep, but what the hell).

[/quote]

+1 on this,
I did my seals earlier on in the year without doing the bushings... after I write this I am going to go and wash fork oil of my forks.
This time around I think I'm going to do it properly and pull the forks right out and apart give them a good clean and install new bushings, seals, straight rate springs and emulators. Hopefully these new fangled ones Randy has been on about.
Also make sure the seals you purchase are Yamaha and not some generic brand as you will just be pulling the forks down again soon if you skimp out on the seals.

Here's a pic of the fork cap tool I made, its just an 18mm bolt with a 5/8 socket bashed onto the threaded end.

Good luck with it all.

chapindad · May 23, 2011, 12:15:33 PM

Thanks. I think I am going to just replace the fork oil and see. I am bad about scope-creep, just ask my boss. I will leave the rebuild for another project, I think. I just realized yesterday that I need new front pads badly so I will do that and the fork oil.

Also, Thanks for the picture.

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Front Fork Oil