Fork Oil

[Fallen Jim Rides again]

The only place locally that seems to carry the Silkolene Fork Oil is the local Yami shop. Didn't buy my bike from them but the more I visit there the more I think I should have. Anyway, they have Silkolene fork oil in stock if ya want 5w. Can order SFO in 5w 10w etc. No in-between - no half w - no 7.5. They can order Silkolene Pro-RSF racing fork oil and in the 7.5w suggested here so frequently.

The racing oil is more than twice the price of the regular but I didn't spend $700+ on Wilburs Shock and springs to worry about a couple of buck. I do want to be sure I'm ordering the right stuff.

Might I impose on the more experienced of you to give advice?

I did read in the Silkolene catalog that the racing fork oil can be mixed to fine tune performance but that was in reference to the racing oil and no similar reference or comment was made about the regular fork oil. I think I read that here too, but thought that maybe someone was getting their leg pulled.

I could experiment but I expect that some one (or many) here have plenty of experience with this and can provide suggestions and education.

Afterwards, or even during, I'm sure some fun can be had at my expense with just the slightest creative misinterpretation of the Topic Title.

I know I would. Oops already did.

Thanks in advance guys.

 

[Bounce]

The only place locally that seems to carry the Silkolene Fork Oil is the local Yami shop. Didn't buy my bike from them but the more I visit there the more I think I should have. Anyway, they have Silkolene fork oil in stock if ya want 5w. Can order SFO in 5w 10w etc. No in-between - no half w - no 7.5. They can order Silkolene Pro-RSF racing fork oil and in the 7.5w suggested here so frequently. The racing oil is more than twice the price of the regular but I didn't spend $700+ on Wilburs Shock and springs to worry about a couple of buck. I do want to be sure I'm ordering the right stuff.

Might I impose on the more experienced of you to give advice?

I did read in the Silkolene catalog that the racing fork oil can be mixed to fine tune performance but that was in reference to the racing oil and no similar reference or comment was made about the regular fork oil. I think I read that here too, but thought that maybe someone was getting their leg pulled.

I could experiment but I expect that some one (or many) here have plenty of experience with this and can provide suggestions and education.

Afterwards, or even during, I'm sure some fun can be had at my expense with just the slightest creative misinterpretation of the Topic Title.

I know I would. Oops already did.

Thanks in advance guys.

I request that they use 7.5w Silkolene if they had it and 10w if they didn't. They put in 10w. When it comes time to do another flush, it'll be with 7.5w if they have to order it.

The trick was that, when I was paying my ticket, there was 7.5w on the shelf behind the parts counter. Grrr...

 

[Geezer]

So is 7.5 really the right stuff? From reading other threads on this I am totally lost about which fork oil to put in when I install my Wilbers springs. One thread talks about 2.5 being the right stuff and this thread says 7.5.

I did read the thread that points to a chart that compares a bunch of different fork oils but that only served to confuse me eveb more. It looks like Silkolene 5W is closer to the stock Yamaha fork oil in viscosity.

 

[SkooterG]

So is 7.5 really the right stuff? From reading other threads on this I am totally lost about which fork oil to put in when I install my Wilbers springs. One thread talks about 2.5 being the right stuff and this thread says 7.5.
I did read the thread that points to a chart that compares a bunch of different fork oils but that only served to confuse me eveb more. It looks like Silkolene 5W is closer to the stock Yamaha fork oil in viscosity.

Well, here's my opinion.

It is confusing as hell. People are waaaaay over-analyzing this. And, despite what others will say, its difficult to give the correct recommendation. You are just going to have to go with what feels good for you.

Forum member Dobias did a bunch of research on this. He is the one using the Silkolene 2.5wt fork oil because it is a close match to the Yamaha 7.5 weight oil. That reference website with the chart you referred to is great info, if you can figure it out. What it does tell you is that fork oil weights are NOT equal from one brand to another. There is no standard or consistency. One brand's 7.5wt is another brand's 2.5wt.

Overall 7.5 weight is recommend for Wilbers springs, but that is with their own oil, which there is no information about, and for which they will not provide info.

So you rolls the dice.......

Wish I could be more helpful. I recommend PM'ing or emailing Dobias. He knows his **** about this stuff, and could probably help you out.

I used MotorEx 7.5wt as many others have. I have no freaking idea if that is the ideal oil or not.

Good luck.

 

[dobias]

SkooterG,

If the oil you are using is Motorex Semi Bath fork oil 5w40, it's a whopping 90.9 cSt viscosity @40C. And that is as heavy as most any fork oil available.

I can't find Motorex 7.5w.

By comparison, the Silkolene Pro RSF 2 1/2w I use is 13.6 cSt @40C.

The Yamaha #01 oil is 15.6 cSt @40C.

dobias <_<

 

[Fallen Jim Rides again]

dobias, help me out here. You say you are running the Silkolene Pro RSF 2 1/2w, I assume in the FJR. This is quite a bit lighter than the 7.5w Klaus reccomends but then the chart here refered to repeatedly demonstrates that there is so much variation between brands as to make the w numbers almost meaningless.

Why such light fork oil?

I can see that the Silkolene Pro RSF provides superior temperature stability so I plan to stay with that brand. However, many here are going with much higher vis and seem to be getting good results. Or at least they are happy.

Except maybe Bounce.

Bounce, was the fork oil the shop put in yours that you have spoken of the regular Silkolene Fork oil or the Silkolene Pro RSF? Here there is wide variation in one brand and knowing which they used could be very helpful since I know that you feel that the existing oil isn't light enough.

I mean to clear the waters (oils?) here if I can.

Right now I'm leaning toward the Silkolene Pro RSF 5W after looking at the chart and reading others experiences. It appears to be very close to what Rad is using and more temp stable.

FWIW I have a riding weight around 240 - 250 and I often ride two up with some 50+ lbs variation in passenger weight. (100 - 150) Usually have bags on with some junk in them but not packed heavy or anything. No 10/10 riding but I do like it a bit sporting.

 

[SkooterG]

SkooterG,
If the oil you are using is Motorex Semi Bath fork oil 5w40, it's a whopping 90.9 cSt viscosity @40C. And that is as heavy as most any fork oil available.

I can't find Motorex 7.5w.

By comparison, the Silkolene Pro RSF 2 1/2w I use is 13.6 cSt @40C.

The Yamaha #01 oil is 15.6 cSt @40C.

This is what I used, but in 7.5w:

Which you can purchase HERE.

 

[dobias]

Fallen Jim Rides Again,

Jim, I'm 220 lbs., stripped for action, ride 99% of the time with my 140 lb. wife and also carry stuff.

If I were you, I'd use the 80mm air space dimension. It helps prevent bottoming with the weight we're carrying when in extreme braking &/or hitting potholes.

If I were to have my forks rebuilt with new innards, I'd certainly use what the rebuilder would recommend. Why would anyone want to change from what viscosity Yamaha has determined is correct for their fork valving?

Their Yamaha #01 fork oil viscosity is 15.6 cSt @40C. The Silkolene I use is almost exactly the same. I don't concern myself with the cSt viscosity @ 100C because I'll never push the bike that badly without taking it on a motocross course & trying to win.

As long as the viscosity is close to Yamaha's #01 fork oil, I don't think the brand matters that much. I've just had good luck with Silkolene.

Sorry, but I can't bring myself to change to an unknown viscosity of Wilbers oil just because I'm using their slightly heavier fork spring.

As usual, YMMV.

dobias <_<

PS: SkooterG, I've asked for the Motorex fork oil viscosities but I'm not gonna hold my breath.

 

[FJRmogul]

How much does one need to purchase, not including a flush?

 

[MCRIDER007]

How much does one need to purchase, not including a flush?

Each fork is going to take around 24 ounces depending on the air space you decide to use, so you really need to buy 2 quarts. Premium fork oil is pretty expensive to use for a flush so I used a $2 quart of ATF to flush mine.

 

[FJRmogul]

@MCRIDER007

I've decided to use the Silkolene Pro RSF 2.5 and at $15 each I use something else for the flush. Thanks.

 

[radman]

I used Maxim 7wt. No special reason, just was the right weight and looked to be a good product, priced about right for a premium product, it was blue, and they were out of Silkolene. FWIW, I highly recommend using tranny fluid as a flush, follow up with brake clean (I dump half a can in each leg, pump a couple times, then drain well, then add the fluid you'll actually be using). This insures spotlessness, as well as insuring no other fluid remains, as after a few minutes all traces of the brake clean have evaporated. I clean and polish the outside of the legs to perfection so as to insure bug and dirt free legs during the max pumping I'll be doing during the maintenance , finishing up with a paper towel wet with fork oil, then a dry one. I'll go thorugh 2-3 cans of brake clean during a fork maint job, should give some idea as to the importance I put on cleanliness.

 

[Fallen Jim Rides again]

Rad, how does the Maxim 7w feel? Ok, that may not be the right question.

What is your take on the suspension using that oil? IIRC that is the racing fork fluid (125/150), is that right? Looking at the chart on the Peter Verdone site that oil has the same cSt @ 40c as the Silkolene Pro RSF 5w. and I can get that in a couple of days so I'm still leaning pretty far in that direction.

Klaus' instructions say simply 7.5w fork oil. The more I research this the more confusing it becomes. The numbers are all over the place on the ratings by the manufacturers and any kind of objective or standardized reference point.

I agree mostly with dobias on the design of of the valving but I know that given a specific valving it is routine to modify the ride by changing the oil vis to get the range of adjustment for a given riders style and weight. or just his preference. Still I wouldn't want to get too far off the mark for those valves or from Wilbers specs and the time spend researching is cheaper than trial and error here. Never mind that I want to ride not spend all my time working on the bike. Could have bought a old HD if that is what I wanted. :bleh:

Several here have used higher vis oils and seem to be satisfied but then Bounce has said that the 10w the shop put in his isn't entirely satisfactory.

Also, living in Texas as I do and given how hot it can get here I do want temperature stability for a consistant ride.

Am I overthinking this. probably but i want to get it right the first time if I can. Hopefully with some input from others experience here I can figure out what I want and ultimately we can have a good idea how different products compare when used in the FJR.

 

[Fallen Jim Rides again]

Oh, and I have to add tranny fluid and some more brake cleaner to the shopping list.

Rad, how do ya get the fluid out of the trannys up there? I only know one and he/she is pretty tough. I can take 'em but would rather be done with it quickly. Advice?

 

[radman]

Actually haven't ridden with it yet-but I suspect it will be little different than any other light to medium oil. I have run 10w and not liked it on this platform-much better with the lighter stuff. With the range of adjustments that can be applied, the lighter oil is more compliant and reacts more accurately to adjustment than the heavier stuff, which tends to negate fine tuning due to it's reluctance to flow readily through the small passages. The Feej fork doesn't really work hard enough I think to need the viscosity boost of a heavier fluid. Guys that ride hot and/or desert a lot might gain some benefit from a slight bump, 10 from 7.5, 7.5 from 5 etc, but I think it's best to run the lightest oil you can, it's just easier to adjust around IMHO.

 

[Zipper]

I'm aware that the brand of oil isn't nearly as important as the marketing geeks would lead you to believe :bleh: (as long as it's the right weight and of resonable quality). I'm not going to install my springs right away, but I have picked up a couple of quarts of PJ1 7.5 weight that I intend to use unless someone has something really bad to say about the brand or weight.

Does anyone have any experience with the PJ1 oils that I should be aware of?

TIA

BTW, I took the FJR out for the first ride with the new Wilbers shock. WOW!!

 

[dobias]

Zipper,

The PJ-1 fork oils are a good example of the inconsistant viscosities out there.

PJ-1 Cartridge Pro Fork Fluid (3.5wt) is 14.6 cSt @40C

PJ-1 Fork Tuner (2.5wt) is 26.1 cSt@40C

PJ-1 Fork Tuner (7.5wt) is 27.5 cSt@40C

PJ-1 Fork Tuner (5.0wt) is 31.2 cSt@40C

PJ-1 Fork Tuner (10Wt) is 33.9 cSt@40C

...and, no, there aren't any typos! The Fork Tuner oils are so close in viscosities, I think PJ-1 has a one-size-fits-all oil and label the same oil with different SAE wt's. for the unsupecting public.*

If I were using PJ-1 I'd go with the Cartridge Pro Fork Fluid (3.5wt).

dobias <_<

* I ran into that with GE. I needed a fractional motor to get an automotive paint shop operational before Monday morning production. I dragged a GE plant Mgr. out of bed on a Sunday to get one. We walked the assembly line to find the exact motor without luck. He grabbed another one with a much higher HP/amp label & relabeled it. He swore they used the same motors (within any given range) labeled differently for various needs.

 

[MCRIDER007]

I think Radman makes a strong case for using lighter oils but I installed mine before I read his comments. I already had a quart of Belray 10 wt and so I bought a quart of 5 wt and mixed them together. My first suspension settings were 4 lines of preload and the rebound/compression set one third from full soft. It was a nice ride but I thought I had excessive nose dive when braking. I went to 3 lines of preload and to rebound/compression set in the middle and that seemed to be pretty good, it definitely was stiffer than the prior setting. I am still going to experiment but changing the settings does effect how the front forks respond and since my settings are currently in the "middle" it gives me a lot of flexibility to adjust.

 

[dobias]

mcrider007,

Reducing the airspace will reduce the nose dive without altering the ride settings.

dobias <_<