Changing 2006 Gen 2 Fork-Oil

[Jeff Overman]

Need to change Fork-Oil on my Gen 2; don’t want to take the Fork’s off and I’m planning on using a Syringe with plastic and metal-tubing to suck it out. Oil has never been changed and it’s shot! Has 46k miles on her!

Is there anything it need to know before it get started? For example; should I use original 15W oil or go to 5W?
Thank you in advance for your help concerning this matter!

Sincerely,
Jeff Overman

 

[rbentnail]

Need to change Fork-Oil on my Gen 2; don’t want to take the Fork’s off and I’m planning on using a Syringe with plastic and metal-tubing to suck it out. Oil has never been changed and it’s shot! Has 46k miles on her!

Is there anything it need to know before it get started? For example; should I use original 15W oil or go to 5W?
Thank you in advance for your help concerning this matter!

Sincerely,
Jeff Overman

I highly recommend you read the service manual procedure for checking level after refilling. Done fully compressed.



The fluid itself has been discussed many times, mostly in that there is really no "standard" for weight designations of suspension fluids. I use Honda SS-8, 195 lbs, strickly solo rider. Do a search and you'll likely find charts comparing different mfr's fluid weight comparisons. Do not trust what is on the bottle.

 

[RossKean]

I doubt you will be able to do a satisfactory fork oil change without removing the forks from the bike.

 

[fastpappy]

Just consider the sediment that has probably collected at the bottom, that is what you want to get out. Some people actually do a refill/pump and flush before the final refill. Just my 2cents.

 

[RossKean]

Some people actually do a refill/pump and flush before the final refill.

I do that but only with a few ounces. I also like to let the forks hang upside down for an hour or so to drain out everything. I have heard of some who use inexpensive automatic transmission fluid to displace residual cruddy fluid but then you would have to displace that with a few ounces of fork oil.
Note: Original fluid is less than 15W!!
I used to use Belray 5W. Switched to Maxima Racing Fork Fluid as recommended by Traxxion for my AK20 setup.

See the following - neither complete nor recent.

 

[escapefjrtist]

Echoing others, remove the forks and do a flush and fill with the proper suspension fluid. Anything less and you're leaving a lot of contaminates in the fork and cartridge.

~G

 

[Oldjeep]

Removing the fork tubes is simple. No reason to try to shortcut the process. Even with them off, flushing them is a pain if you are not tearing them down completely.

 

[Auburn]

at 46,000 miles, your bushings are shot too. You should rebuild the forks and replace the bushings and seals. The Maxima oil recommend above is really good.

 

[RossKean]

Note: With 46,000 miles, you may be looking at fork seals and bushings before too long. I think I did mine first at 60,000 miles or so but I probably could have extended that a bit if I had used a SealMate (or similar) when it started leaking. You might get another 5,000 or 50,000 miles before irreversible leaking but the Teflon coating on the bushings will be totally trashed long before reaching the 50K. Probably not great at your current 46,000 miles.

As Oldjeep said, removing the fork tubes is easy. Bike on centerstand. I use a 2 x 4 on a car scissor jack under the header pipes to lift the front end. Remove fender and front wheel. Three Allen pinchbolts on each side and its done. Pull forks out the bottom and be careful they don't slide and hit the garage floor.

If you do decide to go for bushings and seals, have a look at the following...
https://www.fjr-tips.org/maint/ForkSeal-BushingReplacement.pdf

The Maxima oil recommend above is really good.

The one recommended by Traxxion for their setup was Maxima 125/150 Racing Fork Fluid but I am not sure how that would work for OEM cartridges.

 

[GPRIDER]

I guess you can call me crazy, but I find it hard to believe fork bushings are worn out at around 50k on a high milage bike if the fluid is maintained properly.

GP

 

[RossKean]

I guess you can call me crazy, but I find it hard to believe fork bushings are worn out at around 50k on a high milage bike if the fluid is maintained properly.

GP

I guess it depends on your definition of "worn out". I'm pretty sure that dimensions are still well within whatever specs Yamaha has for them. There is no doubt that the Teflon (or whatever polymer they use) coating is worn off to a significant extent. I would not proactively replace bushings but would do them if I had to change seals anyway because of a leak I couldn't stop by cleaning the seals.

Does it matter that the polymer coating has worn off especially since they are constantly bathed in oil? I don't know the answer to that one but with the "slide hammer" method of separating the forks is used to remove the seals, the upper and middle bushings are almost invariably damaged. I have never tried to remove/replace the seals without separating the forks...

 

[Oldjeep]

I guess you can call me crazy, but I find it hard to believe fork bushings are worn out at around 50k on a high milage bike if the fluid is maintained properly.

GP

I replaced mine at 19K? and they were awful worn. Now that I have thicker oil, better springs I don't expect that to repeat - but I was amazed how worn they were.

 

[RiderJoe]

I agree with @Oldjeep and @RossKean 's recommendations above. If you want to change the fork oil, the effort of doing that properly (by removing the forks) gets you to a point that changing the bushings and seals at the same time would be only half more amount of work, and that would give you another 46K miles+ of piece of mind. Not replacing all accessible items while the tubes are apart would only mean that most likely you will need to tear everything down again in a few more thousand of miles and do the replacements then. That equals to a lot more time, effort, and more money (as you will need to change the fork oil again). This is of course, how I would approach things - do what works for you.

Now that I think of it, on a lot of cars equipped with timing belts it is recommended to change the the belts at 80-100K miles. At the same time it is a common, and good practice to also replace the water pump and the belt tensioner. Why? Not necessarily because they are bad at the time, but because by 100K miles they are at the end of their life cycle. Since most of the cost is in the labor to take the front of the engine apart to replace the belt and not in parts costs, adding the cost of a new pump or belt tensioner becomes negligible compared to having to pay the mechanic the same (whole) fee again just to replace the water pump in a few(?) thousand miles.

 

[Mr_Canoehead]

My fork seal on one side blew out at about 40k miles. I did the full rebuild at that time and my bushings were pretty worn. The bushing change is pretty easy and the bike felt more solid afterward. Highly recommend doing the whole thing.

 

[thefix]

The issue everyone has but dont know or admit too is…. Are your forks perfectly aligned to each other? If you have never done a stiction test and correction… then your bushings are surely poo. I did my alignment that made my forks much smoother than when i got it. Luckily bike had low miles. The manual simply says make axle end flush with tube. There is more to it. Just moving the right fork a few thousandth can make big difference. Dealers doing tires don't read the manual much less check fork action. I also will be changing my fork oil … less than 16k. Removing tubes

 

[RossKean]

...If you want to change the fork oil, the effort of doing that properly (by removing the forks) gets you to a point that changing the bushings and seals at the same time would be only half more amount of work...

Except for two possible issues.
1) Sometimes, the forks do not come apart as easily as you might like! The middle bushing can get jammed under the top bushing and may be a bitch to get out without damage. A heat gun to warm the upper bushing region of the fork can be your friend.
2) You need a special tool to seat the middle bushing. (see the reference I linked, above)
https://www.fjr-tips.org/maint/ForkSeal-BushingReplacement.pdf

@RiderJoe is correct, compared to a proper fork oil change, it does not necessarily take much longer to do the bushings and seals if you know what you are doing and have the right tools. My advice would be to do it yourself if you are comfortable with this stuff. If not, go to a competent shop - not like this is something that has to be done very often.

 

[Auburn]

Also, search around here on the forum there are a few threads with info on how to obtain or build your own special tools need to do a complete fork service.

 

[Whooshka]

Hint: Loosen the upper clamp pinch bolts first before you loosen the fork caps

And I'm not sure you can get a hose/syringe past the washer on top of the spring. I've tried it on another bike and no-go.