captainscarlet Posted February 14, 2019 Share Posted February 14, 2019 As I have mentioned in other threads I am in the process of updating my suspension. At the front end this means new K-tech springs at 9.0 Nm and obviously fresh oil. I have trawled the numerous threads on this board and have understood that a fork oil with a low cST value is what's required. On that basis I have bought some of this stuff: Red Line Synthetic Oil. ExtraLight 2.5wt Suspension Fluid WWW.REDLINEOIL.COM Popular in NASCAR's professional categories, motocross, and road racing, where top engineers try to run the lightest fluid possible that maintains its viscosity and stability. It has a cST value of 8.3. I received two bottles of the stuff yesterday and confess I'm now a little unsure. It is very fluid and to my untrained eye looks more like blue coloured water! Have I gone too light? CS Link to comment Share on other sites More sharing options...
WindsorPhil Posted February 15, 2019 Share Posted February 15, 2019 I ordered new spring for mine from Stoltech. Their advice was to use 5W if revalving the front end and 10W if we are just replacing springs. I have the springs but won't get to gauge the results till spring. Link to comment Share on other sites More sharing options...
Jiri Posted June 4, 2019 Share Posted June 4, 2019 I am 224 lbs with all the riding gear. I replaced front springs by progressive Wilbers with stiffness 8,5 - 10,5 N/mm (free lenght 295mm). Replaced fork oil by lighter - cSt 40°C = 6,7 (2,5W SAE Wilbers Zero friction), height 150mm under top. After many tests I finished with 10 clicks from full hard (I tried to find the least possible damping without feeling bouncy). Front sag 30mm free/45mm with rider. It works fine now. Link to comment Share on other sites More sharing options...
dmanteigas Posted July 11, 2019 Share Posted July 11, 2019 Hi All, I have a Tracer 900 GT with 26000kms and it's now time to do front fork maintenance. Should I stick with Yamaha standard fork oil or there are better alternatives? Link to comment Share on other sites More sharing options...
StealthAu Posted July 11, 2019 Share Posted July 11, 2019 3 hours ago, dmanteigas said: Hi All, I have a Tracer 900 GT with 26000kms and it's now time to do front fork maintenance. Should I stick with Yamaha standard fork oil or there are better alternatives? If you are able to setup your compression and damping within the adjustable range, stick with the same fork oil. Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted July 11, 2019 Supporting Member Share Posted July 11, 2019 6 hours ago, dmanteigas said: Hi All, I have a Tracer 900 GT with 26000kms and it's now time to do front fork maintenance. Should I stick with Yamaha standard fork oil or there are better alternatives? Like @StealthAu suggested, if the current fork action works for you, don't change from what you are using. Most fork oils come in various viscosities - 2.5w, 5w, 7.5, 10w etc. with the thought that you can "fine tune" your fork action with thicker or thinner oil. ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
koth442 Posted July 11, 2019 Share Posted July 11, 2019 Fork oil can be pretty thin stuff. '15 FJ09 Link to comment Share on other sites More sharing options...
streeter Posted August 18, 2019 Share Posted August 18, 2019 I stayed with the stock springs but went with the Red Line fork oil. I'm pretty happy with the forks now. Before, they were very harsh going over sharp bumps, but now I don't even notice. 1 Link to comment Share on other sites More sharing options...
Premium Member 2and3cylinders Posted August 20, 2019 Premium Member Share Posted August 20, 2019 Fluid weight is relatively meaningless within a range. Always gauge viscosity on the "oil's" Cst @ 40C relative to its Recalculated Viscosity Index (VI); the higher the VI the better. Cst can vary greatly among the same "weight" oil. A good starting Cst, which is relatively low but not too low around 16 Cst. Search for "fork oil weight table" like http://mahonkin.com/~milktree/motorcycle/fork-oil.html A comparatively readily available 16 Cst fluid due to the preponderance of Honda dealers is Honda "SS-7" made by Showa is 16.44 with a recalc'd VI of 119. Kayaba / Yamaha 01 = 15.60 @ 96. If you can find it though pricey, Motul shock oil (2.5-20) is 16.10 @ 403! Or you can blend your own based on the CST and vi using Mixing viscosities | Widman International SRL 2 Link to comment Share on other sites More sharing options...
Tripletrouble Posted March 28, 2020 Share Posted March 28, 2020 There is a lot of misinformation on fork oil. Simply. One brands 10w can have a similar effect to another brands 5w. So while you may think your putting in lighter oil, you may not be. So the 'I've put in 5w and now I can beat Marquez' may not be helpful at all if you use a different brand. It's not the brands quality we're talking here, it's the consistency, thin/thick at a given temperature. The CST number is what you need for reference. For example...Your recommended Yamaha 5w ( kayaba 01) is 15.6 which is very low, or thin. Castrol synthetic 5w is a whopping 28.00 ! Here's a link to a chart for you to ponder http://mahonkin.com/~milktree/motorcycle/fork-oil.html Link to comment Share on other sites More sharing options...
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