Fork Oil

[Daredevil]

hey guys, about to get my fork oil done to my 05 r6. I've done 4 track days and i have about 6500miles on my bike, without a single fork oil change, i figure now would be a good time. Not only cause it should be done but im signed upf or 3 track days in 3 weeks.


What weight should i go with? I just figured i should go with Motul, since that's the only brand i really know anything about. (brakes)
Do i need to replace my seals (they are perfectly fine, but wasn't sure if i should do it all at once)
and if it matters im about 5'8" 150 with gear.
thanks

[Jello_Biafra]

7wt, it's only gonna get warmer.

[kyles here]

i have 14k and 10 track days on mine, think i should mine:laughing

[afm199]

put in what it came with. Probably 150Cs/ 5 weight

[Daredevil]

put in what it came with. Probably 150Cs/ 5 weight

well, i only ask because that is what i would assume to do, but my question is, how can i benefit from putting heavier oil in, or lighter?

[afm199]

the lighter the oil the less temperature affects viscosity. On the old damper rod forks with 20 wt oil they were very very stiff when cold.

Heavier oil will increase the damping. Mostly the rebound damping. It affects the rebound 2 or 3 times as much as the compression. If you need more rebound damping (your current adjustments do not allow enough) then go SLIGHTLY heavier. Do not do this unless you need to. If the forks work fine now, dont change the oil viscosity.

[norcalzx10r]

Check your Service Manual. Stock oil height and weight is fine. Fresh oil always a good idea. Unless your seals are leaking, I would just change the oil.

[Evol-E]

Seals are fairly cheap and since the forks don't come apart as often as they should I would suggest just changing the seals while your in there.

[Daredevil]

according to the stealership my bike has 10 weight oil in it :o

[afm199]

according to the stealership my bike has 10 weight oil in it :o

I seriously doubt it . Check the manual, don't listen to some phone voice. It is possible but not many cartridge forks I know of use 10 wt oil. Too heavy.

The race tech site says 06 R6s use US1 or 3.5 to 5 weight, I would go with 5.

[Yody]

Do you have the USD forks ore conventional?

[enzo76]

Desmoto just changed my 05 R6 fork oil with 5wt. I think that's Yamaha's recommendation, as well as Desmoto's

[kyles here]

would i be ok just turning it over and pouring it out? or is there something else to do?

[Jello_Biafra]

Pour it out into a graduated container and let drain overnight. Discard bad oil and replace with equal amount of fresh stuff.

[Daredevil]

thanks guys ill have my mechanic put 5 weight in

[Daredevil]

thanks guys

i just got off the phone with dave moss. he told me 10 weight is too heavy, 5 is too light and i hsould go with 7 weight for optimal results. my mech is putting it together tomorrow am, can't wait.

[kxmike]

thanks guys

i just got off the phone with dave moss. he told me 10 weight is too heavy, 5 is too light and i hsould go with 7 weight for optimal results. my mech is putting it together tomorrow am, can't wait.


+1...that's about what I run , usually mix 5 weight and 10 wt to get the desired viscosity.

[uraniaclio]

would i be ok just turning it over and pouring it out? or is there something else to do?

I think so. I've heard best way to do this is to measure the air gap. I take that to mean distance between the lip of the outer tube compressed and the fork oil with springs out. I was looking through the Triumph service manual and that's what it says. I've heard others measure fork oil by volume so I'm not sure which is best. I would think volume would change with debris from the internals of the forks.

[afm199]

I think so. I've heard best way to do this is to measure the air gap. I take that to mean distance between the lip of the outer tube compressed and the fork oil with springs out. I was looking through the Triumph service manual and that's what it says. I've heard others measure fork oil by volume so I'm not sure which is best. I would think volume would change with debris from the internals of the forks.

Measure with spring out. measure with fork collapsed all the way (if there is a zip tie, remove it so the fork bottoms on the dust seal) measure to the lip of the HARD CHROMED tube. (the one that hold the oil) on USD forks the tube will be the lower one, on regular forks, it will be the only one. Do not measure by volume.

BTW the best measure of fork oil is centistokes and the actual viscosity on lighter oils varies hugely, with some 5 weight being heavier than other ten weight.