Fork Oil Change Made Easier

[HotRodZilla]

Want a better way to service your forks?

Call dealer, make appointment. Drop off bike. Go do whatever you want to do. Get phone call, go pick up serviced bike. Pay nice people for doing that bullshit for you. Ride away happy.

You can thank me later.

 

[hppants]

No special tools required for the "A" model AFAIK

I added some more language to the "remove fork cap" step to make things a little more clear.

I can't find anything on the oil quantity or type. For my Gen 1, I used the Honda 7wt, which was extremely close to the Yamaha factory oil. We will need others to weigh in on this.

 

[LKLD]

Want a better way to service your forks? Call dealer, make appointment. Drop off bike. Go do whatever you want to do. Get phone call, go pick up serviced bike. Pay nice people for doing that bullshit for you. Ride away happy.

You can thank me later.

Actually 'Zilla, I looked into that first. $250ish sounded a bit steep to me, so figured I'd have a go at it on an upcoming tech day.

 

[bluesdog]

You may want to loosen the upper triple clamp bolts prior to loosening/removing the fork caps, because the upper clamps exert pressure on the threaded portion of the caps when they are tight.

When refilling the forks, slowly and carefully exercise 'em a few times and check the level again before re-assembly.

 

[taodow]

Any one know the result of having a tad more or less than specs. I ask because my 06 manual says to bleed the forks. Haven't figured the bleed, book gave no process.

Does state 3.62 in. from top which I measure with a caliper.

 

[hppants]

Well, it's a hydraulic piston. Too much oil will make the system stiffer, and WAY too much oil will probably cause the seals to blow. Too little oil will make the system more spongie and the dampening will be less effective.

You don't need to measure it with a caliper. Get a wooden paint can stirrer and make a knife scratch (fine line) on it 3 5/8" from the end. Add oil until you it reaches the mark. As Bluesdog points out, you will need to burp out the air by exercising the fork. So fill the fork in two stages. Put about a 1/2 pint in there first, burp out the air, then top off the fork with the remaining amount. You will fill with the fork fully extended. Once filled, add the spring, spacer, and washer. Hold the fork extended with one hand firmly while you install the fork cap. If you let the fork collapse, the oil will overflow, make a big mess, and you will have to start over on your measurement.

Also agree with B/D regarding the order of things - loosening the upper triple clamp first will make breaking the fork cap much easier - I had forgot about that part. I'll change my previous post to reflect that.

 

[gixxerjasen]

Want a better way to service your forks?
Call dealer, make appointment. Drop off bike. Go do whatever you want to do. Get phone call, go pick up serviced bike. Pay nice people for doing that bullshit for you. Ride away happy.

You can thank me later.

And no one names a screw up/procedure after you.

Wait a second...what am I even doing in this thread in the first place? Oh wait...I can change the fork oil, no problem. I have the motion pro tool. Worked well, though I'm always a fan of DIY tools.

 

[MCRIDER007]

I can't find anything on the oil quantity or type. For my Gen 1, I used the Honda 7wt, which was extremely close to the Yamaha factory oil. We will need others to weigh in on this.

I think you are referring to Honds's SS-7 Suspension Fluid which actually is a 5wt oil and has similiar viscosity to Yamaha's 01 fork oil that was recommended for the GEN1s.

The purpose of the oil height recommendation is actually a back door way to have the correct amount of air inside the forks so the compressed air can add additional resistance at the end of the fork's compression stroke to help prevent bottoming. Too much oil decreases the air volume resulting is a much higher ratio of compressed air and can blow the seals; too little oil reduces the air resistance at the end of the stroke but does not effect damping unless the oil level is so low it is below the top of the cartridge.

The recommeded oil height is also a function of the fork spring weight. The suspension pros usually recommend a larger oil height (actually less oil) when you install heavier springs.

 

[LKLD]

I saw it mentioned that Gen III's have different amounts in each fork. Any idea what those are?

 

[MCRIDER007]

I saw it mentioned that Gen III's have different amounts in each fork. Any idea what those are?

The 13A service manual says an oil height of 106mm in the left side and 90mm in the right side.

 

[hppants]

Mc007 - you are correct. It is the SS-7, and indeed, it is 5wt oil.

Is that the recommended oil for the '14A?

 

[MCRIDER007]

Mc007 - you are correct. It is the SS-7, and indeed, it is 5wt oil.
Is that the recommended oil for the '14A?

Yamaha recommends their M1 fork oil for the 13A (and numerous other bikes they sell) and claim it is a "zero" weight oil....which is very unlikely....but I have not been able to find what viscosity the M1 oil actually is. I plan to use SS-7 when I change the fork oil in my 13A....at least on the right fork. I don't think it matters what oil you put in the left fork since it doesn't have any damping.

 

[escapefjrtist]

I saw it mentioned that Gen III's have different amounts in each fork. Any idea what those are?

The 13A service manual says an oil height of 106mm in the left side and 90mm in the right side.

...so what do you suppose we should do with my 15A?

--G

 

[RaYzerman19]

The "bleed" is excercising the cartridge up and down to expel any trapped air, before the springs, etc. are reinstalled. Gen II stock oil level is 98 mm IIRC, but those with aftermarket springs, or those who "tune" their suspension, can vary the oil level lower to get more air cushion.... or follow the aftermarket springs supplier's oil level recommendation, e.g., mine is 130 mm. from top of fork tube. Gen III is different because you have different damping side to side.

Torque spec for fork cap...... using your 24mm wrench, just snug it in. The O-ring and triple clamp will hold it, don't worry.

 

[MCRIDER007]

I saw it mentioned that Gen III's have different amounts in each fork. Any idea what those are?

The 13A service manual says an oil height of 106mm in the left side and 90mm in the right side.

...so what do you suppose we should do with my 15A?
--G

I would do exactly the same as you did when your forks were on your '09 but you are going to have to find a new source for your Honda SS-8 because I gave you all I had in stock.

 

[Fred W]

You don't need to measure it with a caliper. Get a wooden paint can stirrer and make a knife scratch (fine line) on it 3 5/8" from the end. Add oil until you it reaches the mark. As Bluesdog points out, you will need to burp out the air by exercising the fork. So fill the fork in two stages. Put about a 1/2 pint in there first, burp out the air, then top off the fork with the remaining amount. You will fill with the fork fully extended.

No, actually, you fill the fork and measure the level with the fork fully compressed.

I don't think it matters what oil you put in the left fork since it doesn't have any damping.

Not sure that is true. The left leg still has a damper cartridge in it, but it is not adjustable. Only the right side has the ability to adjust the damping, but they may both contribute to it. Why else would they bother putting oil in it?

As for the two different oil levels, that is surely a mystery. The springs appear to be the same, so would displace the same amount. Why not have both at the average height? That would theoretically provide the same amount of air spring.

 

[hppants]

Fill compressed? That is different from the Gen I. Doing so there would cause the oil to over flow. Leads me to believe the Gen II uses substantially less oil than the appox. 650 cc for the Gen 1. Interesting in that I find the dampening for the Gen III is much more effective than even a fresh fork oil change in my Gen I. Perhaps my springs were getting tired, though.

Thanks for the clarification, Fred.

 

[MCRIDER007]

I don't think it matters what oil you put in the left fork since it doesn't have any damping.

Not sure that is true. The left leg still has a damper cartridge in it, but it is not adjustable. Only the right side has the ability to adjust the damping, but they may both contribute to it. Why else would they bother putting oil in it?

As for the two different oil levels, that is surely a mystery. The springs appear to be the same, so would displace the same amount. Why not have both at the average height? That would theoretically provide the same amount of air spring.

Motorcyclist magazine was the first to report that the left cartridge was "dead" with no damping. I found this hard to believe and contacted Traxxion because I had a set of AK-20s I wanted to install in my 13A. Traxxion confirmed that the left cartridge was dead as did GP Suspension at a Tech Day later that year. You still need oil in the fork for lubrication and rust prevention but I wouldn't be surprised if ATF would work as well as fork oil since I used ATF in my Venture Royales for 90K miles (damper rod system) after my dealer told me that is what they used for fork oil.

 

[Fred W]

Fill compressed? That is different from the Gen I. Doing so there would cause the oil to over flow. Leads me to believe the Gen II uses substantially less oil than the appox. 650 cc for the Gen 1. Interesting in that I find the dampening for the Gen III is much more effective than even a fresh fork oil change in my Gen I. Perhaps my springs were getting tired, though.
Thanks for the clarification, Fred.

Actually, it has always been measured with the fork compressed, even on Gen 1's. If you filled it to the specified height with the fork leg extended and then stuck a spring in it you'd have practically no air space at all. You just may be dis-remembering the process.

I don't think it matters what oil you put in the left fork since it doesn't have any damping.

Not sure that is true. The left leg still has a damper cartridge in it, but it is not adjustable. Only the right side has the ability to adjust the damping, but they may both contribute to it. Why else would they bother putting oil in it?

As for the two different oil levels, that is surely a mystery. The springs appear to be the same, so would displace the same amount. Why not have both at the average height? That would theoretically provide the same amount of air spring.

Motorcyclist magazine was the first to report that the left cartridge was "dead" with no damping. I found this hard to believe and contacted Traxxion because I had a set of AK-20s I wanted to install in my 13A. Traxxion confirmed that the left cartridge was dead as did GP Suspension at a Tech Day later that year. You still need oil in the fork for lubrication and rust prevention but I wouldn't be surprised if ATF would work as well as fork oil since I used ATF in my Venture Royales for 90K miles (damper rod system) after my dealer told me that is what they used for fork oil.

OK, there must not be any orifice restrictions in that damper assembly then. That's pretty weird.

And you're right... why bother using expensive suspension oil in that side if it doesn't matter what it is.

 

[MCRIDER007]

Fill compressed? That is different from the Gen I. Doing so there would cause the oil to over flow. Leads me to believe the Gen II uses substantially less oil than the appox. 650 cc for the Gen 1. Interesting in that I find the dampening for the Gen III is much more effective than even a fresh fork oil change in my Gen I. Perhaps my springs were getting tired, though.
Thanks for the clarification, Fred.

Actually you measure the oil level with the fork fully compressed and the springs out. That is not only the method used for the GEN1, it is how to measure the oil level on every motorcycle that uses conventional or inverted forks. If you were measuring with the forks extended I'm surprised the oil didn't overflow when you added the springs.