fork oil

[penguin1300]

I'm overdue to flush the front fork oil and plan to tackle the task this weekend. I see the factory recomends 10wt fork oil. Is 10wt really the best bet? Or would it be better to goto a heavier/lighter weight?

I'm 185lb and ride very aggressively.

The reason I ask is that I had a YZF600R that I swapped from 5wt to 7.5wt and was extremely pleased. This is a pretty popular move on the YZF board. I'm curious if there is a popular opinion on this topic for the FJR.

I welcome all opinions.

 

[twowheelnut]

The Kayaba stock oil is supposed to be rated at "5" weight. That nomenclature varies from vendor to vendor which means Motuls "5" weight ain't the same as Kayaba's or Silkolene's - maybe. :blink: If you do increase the weight, stay with the Kayaba oil for a fair comparison. If you are going to pop open the tubes, why not upgrade the springs and go with what the spring mfg recommends for your weight and riding style?

 

[evil_henchman]

Viscosity numbers mean next to nothing when it comes to fork oil. This has been posted before but here it is again Click

 

[twowheelnut]

Thanks for that link, evil. I Googled the **** out of it, but couldn't find it.

 

[JimLor]

How come nuttin' is what is seems? I'm doing the change and bought 10w - think now I'll go with Canola oil as it has a high burn temp!

 

[Bounce]

I have 10wt Silkolene in my forks now. Next time it's the 7.5wt.

 

[JimLor]

Bounce - how come?

 

[Geezer]

I'm running with Silkolene 2.5w. It is very close to stock Yamaha 10w. I like it and plan on using the same thing next time.

 

[HaulinAshe]

Maxima also makes an extremely good synthetic fork oil that we use in the motocross world. Their weights behave as "normal".

I use 10w on the FJR, but I rarely exceed 100 mph and don't race it. Both their 3w and 5w fork oils work great in race conditions and rough terrain.

 

[Bounce]

Bounce - how come?

The 10wt is just a bit too harsh. the 7.5wt would make it more compliant under compression without being sloppy like OEM.

 

[JimLor]

Ok, I'm going to ask the question because I'm trying to understand the subject. Peter Verdone's article on Fork oil is chock full of information. For those of us who aren't conversant in the particulars of what the heck he is talking about, let me ask a couple of what I hope are simple questions.

1) Is the final chart listed in order of what we the unwashed would consider "viscosity?" The FJR uses Yami 01 Fork oil (from the service manual) - are those brands listed close by (above and below) similar in performance? Looks like those near the Yami 01 are listed as from 2.5wt to 7wt oils.

2) What is the relative importance of the column headings? Assuming question 1's answer is yes and I chose a "viscosity ( example, column 1 range from 15.00 to 16.50)," what would my second, third, etc priority be in picking a particular brand in the viscosity range (VI next - the higher the number the more consistent the "viscosity" over a temperature range - pretty dramatic differences between some oils)?

Hope someone in the know will take the time to answer this and that it will help folks on the forum!

 

[evil_henchman]

1) Is the final chart listed in order of what we the unwashed would consider "viscosity?" The FJR uses Yami 01 Fork oil (from the service manual) - are those brands listed close by (above and below) similar in performance? Looks like those near the Yami 01 are listed as from 2.5wt to 7wt oils.

The chart lists the oils with the "thinnest" oils which flow most easily on top and the "thickest" oils on the bottom. So I'd say the answer is yes, most people would consider that to be viscosity.

2) What is the relative importance of the column headings? Assuming question 1's answer is yes and I chose a "viscosity ( example, column 1 range from 15.00 to 16.50)," what would my second, third, etc priority be in picking a particular brand in the viscosity range (VI next - the higher the number the more consistent the "viscosity" over a temperature range - pretty dramatic differences between some oils)?

The main thing you want to be concerned with is the first column @ 40C. The only other thing to look at is the third column, viscosity index (VI). The higher the number the more stable it is over a wide temperature range. I wouldn't insist on one with the highest VI rating though I would make sure I didn't get one with a low VI. Mid range should be fine. It's more important in a dirt application because the suspension gets a much better work out and heats up more.

 

[Rickster]

Thanks for that link, evil. I Googled the **** out of it, but couldn't find it.

added the fork oili link to the '06 bin-o-facts. should make it easier to find now.

 

[snikr]

I used the 7.5 wt Silkolene oil when I put in my Wilbers front springs. Just right for my 220 lbs.

Tom