Fork Oil preferences

[jazzyrigged]

What does everyone use for their fork oil? I have heard of people using motor oil of various weights depending on the kind of ride you like. I can either use motor oil available at any parts store or what I already have, or go to the Harley shop which is the only motorcycle store open on Sunday. Anyone have an opinion on the subject. Thanks All

 

[blue900]

for my 81 I have been happy with Amsoil fork oil in 10W

The service Manuel says Yamaha fork oil 10W

 

[pyrocentric]

I'm running ATF in mine. I can't really say if it's good or not.

 

[aldo5468]

I'm using 15w and Progressive springs in my '82 XS650. Started using 15w fork oil in my '94 Virago (in which I also have Progressive springs) because the OEM front springing in these machines was notoriously soft. Decided to use the same approach when I got the 650 last Spring - firms it up a bit.

 

[anysnail]

ooohh, good thread. i've been wondering the same thing myself but i always forget to ask. damn my flakiness!

 

[gentlemanjim]

10-15w Fork oil or ATF. Both have seal swell agnets to keep the for seals pliable so they won;t leak. Engine oil does not have that additive so I would not use it.

 

[bloodthirstysystem]

seeing this thread made me remember that i put motor oil in after rebuilding the forks, temporary to try them out.. i forgot to change it. gonna try the ATF

any type works? figure i'll get DEX3, the old stuff

 

[5twins]

These 35mm forks will work better if you use slightly more than the recommended amount of oil. The stock amount is just under 6 ounces per leg. I run 7 ounces of 10wt. fork oil per leg.

 

[inxs]

- and even better with racetech cartridge emulators

 

[retiredgentleman]

15W-40 diesel motor oil................works great.............firms up the suspension.

 

[larrydreed]

Considering using Marvel Mystery Oil (MMO) for forks. Any discussion or experience with MMO in forks?

 

[jetmechmarty]

Keep in mind that if you increase viscosity, you will slow the high speed damping. That's not always good. See post #8 by 5Twins. That's what I do. Instead of filling with required ounces, I fill to about 130 mm from the top, with spring removed and tube compressed. I'm happy this way. I get less dive, especially braking. So, if you really want to get bucked in the hands, go to 15 or 20 wt and add a second brake to the front wheel.

Also, while experimenting with fork oil wt, don't change brands. Fork oil viscosity numbers aren't consistent between brands. I wish I could tell you where I got that info, but I can't. So, maybe this is just as well ignored. Common sense says, if you're using ATF, MMO, or engine oil, you'll have no point of reference for viscosity experimentation. Fork oil is made for forks. That's what I use. I picked Bel-Ray because that's what was available where I lived.

 

[Gordon in nc]

+1 for Bel-Ray..........been using it for years. 5 wt to 40 wt on the shelf. Yep, that's right 40 wt. Ask me around the campfire what I used that 40wt fork oil for. I use 10 and 20 in most of my bikes.

Gordon (Go Green) in NC

 

[Mailman]

Just as an experiment I bought this to use in my XS2. Walmart Super tech non foaming , recommended for hydraulics. It was inexpensive and my forks seem to work perfectly.

 

[jetmechmarty]

Unless you use your XS650 in AHRMA or WERA Vintage racing, I seriously doubt anyone here pushes their bike hard enough to get the forks to fade. Simply run what feels good for you.

You're right, but what would we talk about?

I recently moved to Mississippi. The roads are terrible. Dirt roads in Georgia are usually better than the paved roads here. Dual disc brakes (unsprung weight) are not an option and I want the forks to move as fast as possible (high speed damping). I'm on OEM forks with 10 wt Bel-Ray. I raised the level as per a previous post.

 

[Mailman]

I recently moved to Mississippi. The roads are terrible. Dirt roads in Georgia are usually better than the paved roads here. Dual disc brakes (unsprung weight) are not an option and I want the forks to move as fast as possible (high speed damping). I'm on OEM forks with 10 wt Bel-Ray. I raised the level as per a previous post.

You know, I hadn’t even considered that. Here in Arizona our roads are generally in really nice , smooth condition. We get very little rain and no snow and ice to heave roads and create pot holes. My forks really aren’t working very hard for the riding I do.

 

[5twins]

Doing the Minton Mods will improve and quicken fork response, especially to the little stuff. I still need to fine tune the forks on my '83. I added 1" preload spacers to the stock springs but it seems I've made them a bit too stiff. My goal was to preload them a little more than the stiffest stock setting (20mm) as even that seems to be too soft many times with stock springs. 1" (about 25mm) seemed like a good size. That would be about another half step stiffer than the stiffest stock setting. But, I also put another washer in there between my spacer and the spring, and I didn't take that into account. It adds probably near another 1/8" to the preload. So, I think I'm going to shorten the spacers to 3/4". Combined with the added washer, that should give me about 22mm of additional preload.

I'm also re-thinking my 7 ounce oil amount. That might be a bit much too, adding a little too much air-spring effect. I know that amount does set my oil level higher than 130mm (5 1/8"). I'm somewhere in the 4 1/4" to 4 1/2" range.

I use real fork oil as well. I don't consider it too expensive seeing that you don't change it nearly as often as motor oil. The manual calls for 4000 mile change intervals but I doubt anyone does that. I probably go a good 10 to 15K on mine. It doesn't get very hot or dirty like motor oil, so I don't see the need for such frequent changes. Since I run fork gaiters, hopefully I'm keeping most of the dirt out.

 

[XSLeo]

The amount of oil your forks hold it doesn't cost much to try a few different combinations of weight and amount.
The older bikes used motor oil. The later bikes used fork oil. ATF has been used for many years.
Experiment a bit and find what works for you.
Leo

 

[pjc]

I use real fork oil as well. I don't consider it too expensive seeing that you don't change it nearly as often as motor oil. The manual calls for 4000 mile change intervals but I doubt anyone does that. I probably go a good 10 to 15K on mine. It doesn't get very hot or dirty like motor oil, so I don't see the need for such frequent changes. Since I run fork gaiters, hopefully I'm keeping most of the dirt out.

Today I disassembled right fork assembly (left tomorrow). I swear that in 39 years the fork oil was never serviced. Foul syrupy mud, what was left in there. I confirmed that the tube had a bit of a bend in it too. Some surface rust and the suspected bent tube were why I bought a set of good tubes from member Kawabunga here. I'm going to use 6 oz atf as I've used atf in other forks with satisfactory result.

 

[mrtwowheel]

Others have said that ATF is about 7-1/2 wt depending on the type and brand. I don't really know about the 1/2, I just added that to sound like I know what I'm talking about. Our farm stores around here have non-detergent oil from 10wt up. That oil is intended for hydraulic and compressor use, probably the same oil that is in the "fork oil" bottles and the "compressor oil" bottles, but costs much less, that's what I use. Non-detergent oil does not FOAM..

Scott