Fork oil level

[Paul]

8 hours ago, Redneckj said:

I took off the spring guide as well when I measured the oil level.   I installed Motul 7.5 weight oil because I still have stock valving.   

you measure oil with spring guides installed, you prob have a bit too much now

 

if you look at the rr instructions it tells you to tighten the spring guide nut down on the spring guide in the step before measuring oil height

Edited July 11, 2022 by Paul

[Redneckj]

2 hours ago, Paul said:

you measure oil with spring guides installed, you prob have a bit too much now

 

if you look at the rr instructions it tells you to tighten the spring guide nut down on the spring guide in the step before measuring oil height

What do the factory Yamaha instructions say?  I have yet to purchase a service manual.  On this  manual, I found online, it says to measure the oil level and then install the spring guide.   It appears to be a factory service manual page.  

 

Edited July 11, 2022 by Redneckj
Cause

[gonebiken]

On 2/15/2022 at 10:54 AM, Hibobb said:

Would have been nice if my manual stated what "a" should be. I guess I have an early version of the manual.

[Prestone]

Its kinda weird they set the oil level from the outer tube since it goes down past the inner tube when seated against the bottom lug, it makes no sence at all

Edited December 17, 2022 by Prestone

[williestreet]

1 hour ago, Prestone said:

Its kinda weird they set the oil level from the outer tube since it goes down past the inner tube when seated against the bottom lug, it makes no sence at all

That pic in the manual is just a standard pics used in probably almost every Yamaha service manual. Some bikes will have the outer higher when collapsed, some equal and some the outer is lower like ours.

 

You always measure from the higher tube when fully collapsed.

 

 

[Prestone]

Yes i have allways done so on my bikes but i can see how people gets pretty confused about it, it would be a simple thing for yamaha to put in a drawing that makes more sence to the do it yourself people out there

[mpatch]

Kind of an odd question I’m guessing nobody will have the answer to. How many milliliters of fluid should I add to raise my oil height 5 to 10 mm? I’m going to have a handlebars off, so adding fluid is very easy but disassembling everything to measure it correctly not so easy. 

[Hollybrook]

@mpatch the correct way to set fork oil level is to use something like this: 

 

https://www.rockymountainatvmc.com/parts/motion-pro-pro-fork-oil-level-tool-p

[Tenerider]

21 minutes ago, Hollybrook said:

@mpatch the correct way to set fork oil level is to use something like this: 

 

https://www.rockymountainatvmc.com/parts/motion-pro-pro-fork-oil-level-tool-p

Exactly. Oil level affects the behaviour of the forks a lot, so it's well worth the additional effort imho.

[mpatch]

23 minutes ago, Hollybrook said:

@mpatch the correct way to set fork oil level is to use something like this: 

 

https://www.rockymountainatvmc.com/parts/motion-pro-pro-fork-oil-level-tool-p

I know, I have one.

To check it the correct way involves disassembling the whole front end and pulling the springs. 

 

I guess if I'm going to tear everything apart any suggestions on what to set the air gap to?

I know with some forks 5-10mm of air gap variation can make a pretty big difference. 

Stock forks other than stiffer springs. 

Edited December 28, 2023 by mpatch

[Tenerider]

Just now, mpatch said:

I know, I have one.

To check it the correct way involves disassembling the whole front end and pulling the springs. 

Yes, unfortunately But it doesn't take that long. Remove the front wheel, brake calipers, ABS sensor, mudguards - max 30 minutes.

Then it's just the eight triple clamp screws, fork caps, and you're done.

[Prestone]

20 hours ago, mpatch said:

Kind of an odd question I’m guessing nobody will have the answer to. How many milliliters of fluid should I add to raise my oil height 5 to 10 mm? I’m going to have a handlebars off, so adding fluid is very easy but disassembling everything to measure it correctly not so easy. 

13ml for 10mm

[mpatch]

37 minutes ago, Prestone said:

13ml for 10mm

Sweet. If that’s accurate it’ll save me a chunk of time. 
Factory is supposed to be 85mm?

[Prestone]

1 minute ago, mpatch said:

Sweet. If that’s accurate it’ll save me a chunk of time. 
Factory is supposed to be 85mm?

Yep… i allways start out at 100mm when testing new CST@ and then add from there, if needed

[mpatch]

35 minutes ago, Prestone said:

Yep… i allways start out at 100mm when testing new CST@ and then add from there, if needed

Does air gap affect these forks a ton? 
I plan on setting them at 100 initially but wondering if 5mm or so lower or higher will be noticeable. 

[Hollybrook]

@mpatch can't you use the Motion Pro tool to determine the current oil level and then move the stop up the amount you want to raise the oil? That should still work with the forks mounted and springs installed. Obviously, the level change will be more with the springs in place. 

[mpatch]

48 minutes ago, Hollybrook said:

@mpatch can't you use the Motion Pro tool to determine the current oil level and then move the stop up the amount you want to raise the oil? That should still work with the forks mounted and springs installed. Obviously, the level change will be more with the springs in place. 

That’s kinda my plan if I can make it work the way it is in my head. 
in my head unscrew the cap, jack the front tire all the way up till the suspension is fully bottomed out and then measure from there. 

Edited December 29, 2023 by mpatch

[Tenerider]

3 hours ago, mpatch said:

Does air gap affect these forks a ton? 
I plan on setting them at 100 initially but wondering if 5mm or so lower or higher will be noticeable. 

It does on mine, but I have Tractive closed cartridges installed. Nevertheless the effect should be similar: smaller air gap gives more progression on the compression stroke. It's noticeable "harder".

[mpatch]

I am half tempted to do it the right way just to see where it’s at from the factory.

[Bard]

For the question about 110mm with fork extended, no dont ever do that.

 

The suspension travel on the T7 is 210mm. If extended level there is only 110mm air gap your suspension travel would be maximum 109mm as fluids do not compress.

 

If you go to racetech website there is a calculator there for spring rate and so on. They suggest for my weight and my spring rate and adventure riding there should be 110 mm gap (collapsed obviously) with fully synthetic 5W oil in the forks.

 

What does small air gap versus big air gap mean in the forks?

Well the hydraulic pressure with small gap is bigger, making the flow of oil slower, also the thicker the viscosity the slower it will be. That means if you go on uneven surface that the forks struggle with keeping up and you get a harsh bumpy ride. The same that happens if you don't bleed your shocks as the pressure builds up, and higher pressure give higher hydraulic pressure and again a harsher ride.

If the level is too low, you can such on air and the suspension will be total crap no damping, like an old American car bouncing around. So the best is to set the level as calculated by suspension specialists as correct for you and your bike.

Remember the stock setup is street biased for 75 kg rider, if that is you do nothing, if not do something.

 

As it is a lot of black magic in suspension (in my opinion) I always use racetech calculator and set up my bike with springs calulated, oil viscosity, oil level, sag and so on from them. That has always made a massive difference in my suspension. I have done it on several bikes, and always loved the difference.

 

So I always ride my bike as is for a while, when I do know it after a season I calculate springs, oil and level and do that. Then I play with settings.

 

For the T7 springs are needed for me back and front, new oil and level in front, and a preload adjuster in front. With that I think I will be fine for a good while, when I one day know the bike so well and if I then ride better than its adjusted for me suspension well then I change shock and forks. But that might never happen, probably will not. I dont ride like Pol Tarres, and have no ambitions to do so.

[Tenerider]

21 minutes ago, Bard said:

 

What does small air gap versus big air gap mean in the forks?

Well the hydraulic pressure with small gap is bigger, making the flow of oil slower, also the thicker the viscosity the slower it will be. That means if you go on uneven surface that the forks struggle with keeping up and you get a harsh bumpy ride. The same that happens if you don't bleed your shocks as the pressure builds up, and higher pressure give higher hydraulic pressure and again a harsher ride.

If the level is too low, you can such on air and the suspension will be total crap no damping, like an old American car bouncing around.

 

As far as I know, this is not correct.

The air gap height determines the rate of the so-called air spring, which works like an additional spring in series (on top) of your coil spring.

The smaller the air gap, the harder this "air spring".

To my knowledge, it doesn't affect hydraulic damping.

 

Mind this air spring behaves like a progressive coil spring. A smaller air gap (i.e. higher air spring rate) may thus help against bottoming out quite well.

For a softer, less progressive feel choose a bigger air gap and vice versa. If it's too small, the whole fork will feel really harsh. A few mm difference affect the feeling quite noticeable.

[Bard]

5 minutes ago, Tenerider said:

 

As far as I know, this is not correct.

The air gap height determines the rate of the so-called air spring, which works like an additional spring in series (on top) of your coil spring.

The smaller the air gap, the harder this "air spring".

To my knowledge, it doesn't affect hydraulic damping.

 

Mind this air spring behaves like a progressive coil spring. A smaller air gap (i.e. higher air spring rate) may thus help against bottoming out quite well.

For a softer, less progressive feel choose a bigger air gap and vice versa. If it's too small, the whole fork will feel really harsh. A few mm difference affect the feeling quite noticeable.

 

For sure it gives air spring, like I stated I am definitely no expert but when I was racing the suspension specialist explained me it also affected the flow and rebound, so I assumed he was correct but he might have pulled my leg for all I know.

 

Anyway the main point is to use new values for a new spring rate, there is a reason why manufacturers and suspension specialists tell you, this spring, this oil type, this air gap, this sag for what you do.

To not follow this by, i had some other oil laying around, or dismissing air gaps etc will make the suspension worse, sometimes way worse that stock.

 

When I was racing there was suspension specialist to setup the suspension for that track that day, ah it does not matter is completely wrong, it matter a lot. 

 

No you probably don't need a specialist for your ride, but use data you easily find to see the right setup. You most likely have no need for new shock and new forks, as you can get a lot more out of the ones that is on the bike.

 

Also if you ride mostly on tarmac in leisurely speed, with an odd well maintained gravel road in between the stock setup will do you perfectly fine. If you push the bike while canyon carving, jump when on not well maintained stuff, and do hard riding on these occasions you will have a lot to benefit from by setting up the bike correct. If your ambition is enduro riding with it like Pol Tarres, change the shock and forks.

 

One of the things many do (an I did) was to splurge a ton of money into modding the bike, money I could have had way better riding gear for myself with being far far far more comfy than I was, money I could have traveled so much for. Don't waste money on the bike until you have to. When you ride so hard the suspension bottoms out with the stock setup, change springs, oil and all that, if this never happens to you why do anything before that happens? When the suspension you put correct springs and all fails you because you ride it so hard it stiffens up and you loose contact with the ground from a correct setup, then you change the shock if that was the weak spot, or the forks. This cost a ton of money, and honestly who rides the T7 that way? Not many that is for sure, some do but very few. I know of perhaps 5 besides Pol that do. And if I wanted to ride like that I would prefer an enduro 250 two stroke to do it with, not the heavy and top heavy T7.