Fork oil on Storm

[Megadan]

If there was only 200ml of fluid in those forks then they were underfilled. Here is why I say that. I borrowed a couple of your pictures for an explanation...

On the bottom of the upper fork tube (Green Arrow) is a seal and dust seal. On the lower fork tube there is a bushing (Blow Arrow). The seal is there to keep the fluid in and the dust seal is there to protect the seal. The bushing is there to stabilize the two tubes but allow movement. That bushing needs oil for lubrication as does the seal. I will come back to the purple arrow in a minute.



The damper would actually be the Orange Arrow. This is evidenced by the holes (Yellow Arrow) that are there to regulate the amount of fluid passing through to provide damping of the suspension travel. Notice this also has a bushing on it that also acts as a damper seal to separate the oil between each side, thus forcing the fluid to travel through the holes. Going back to the purple arrow, this is the area that fluid travels in and out of the holes of, and thus filling the space in the upper fork tube.



So with this all in mind we know that there needs to be fluid on both sides of the damper in order for proper damping to take place as well as to lubricate the bushing on the lower fork tube and upper tube seal, even at full extension. The reason the fork oil volume is much higher for these USD forks has to do with that upper and lower fork tubes being a larger diameter - it has a larger volume. In order to get enough fluid in there to do everything I described it will take 300+ml as you saw since 200ml wasn't even enough to effectively fill the fork lower.

As far as filling it goes. Once you reassemble the forks and slide that upper tube back up, you will fill through that upper tube (Green Arrow) between it and the damper that was held in place with the retainer.

As Pete stated, your fork is essentially just an inverted version of a traditional fork. It has no valving like a more common USD fork with a cartridge. So with that in mind, like my traditional forks, the weight of the fork oil can be used to tune how firm or soft the damping is (slow or fast). I always recommend 15wt as a starting point simply because it is in the middle of the available fork oil weights. From there if you want less or more damping you can simply change to a lighter or heavier weight oil.

Going back to the second picture, the red arrow is pointing to the spring spacer. In this case, I would state that the washer goes between the springs and the spacers just to give the spring a wider seat to rest on. You can adjust the length of these spacers to tune in your preload for setting rider sag. Longer for more, shorter for less.

Looking at the damper makes me wonder if the rebound damping is a part of the center rod that holds the upper damper and spring, or if the upper damper is the rebound and the compression is on the lower. The latter seems more likely to me. I wish I had a set of these forks to do a full tear down on so I could look at all of the parts.

Again, since there is almost no information on this particular fork design, this is merely an educated guess on the actual volume required. If there is somebody that has done a fork oil change on these particular forks that can chime in I would graciously accept whatever they stated they used.

[Duggo]

Well, 300+ is too much. It fills the fork to the rim. So, Im going back to 200.

But, that's not the hard part. How in the hell am I supposed to fill the fork and then compress the fork enough to get the nut and washer on, without the oil draining out onto the floor. Not only is it hard to compress, but it's oil and that make it worse.

If I compress the fork and get the nut on, which is going to be a 2 man job, then how do I get the oil in there?

This is getting aggravating. Maybe I should have taken it over to the dealer and just asked them to charge them up with freshie. But, Im trying to learn here.

[Duggo]

I was a little too pissed off on that last post.

I got the washer and nut on, just muscle it down and quickly put it on there.

Now I have an empty fork. The only way I see to fill it is with a syringe and needle, which I do not have. Maybe Ill get lucky with the other auto parts store in town tomorrow.

Anyway, 300 would be the absolute max ml, right up to the top. I think I'm going to go 250 tomorrow and see what happens.

I'm at an impasse until I figure out a way to get oil down in there.

Thanks for all the help today.

[Megadan]

Originally Posted by Duggo

Well, 300+ is too much. It fills the fork to the rim. So, Im going back to 200.

But, that's not the hard part. How in the hell am I supposed to fill the fork and then compress the fork enough to get the nut and washer on, without the oil draining out onto the floor. Not only is it hard to compress, but it's oil and that make it worse.

If I compress the fork and get the nut on, which is going to be a 2 man job, then how do I get the oil in there?

This is getting aggravating. Maybe I should have taken it over to the dealer and just asked them to charge them up with freshie. But, Im trying to learn here.

This is all good to know info, but it does suck having to be the guinea pig. Like I said, I am unfamiliar with Storms and their forks, so it is merely speculation on my part. If 200ml works, I can't argue with it.

You should still be able to fill the oil through the outer tube. The damper has holes in it to allow fluid to pass through, that is what the yellow arrow is pointing at. Get the retainer and nut back in place, then screw the cap back on, add fluid through the outer, and then add a little fluid at a time and give it chance to run down into the lower. If you need to, add the fluid, screw the cap back on to the upper and cycle the fork a few times. unscrew the upper tube from the cap, add more. This is a common practice when filling USD forks even on mainstream bikes. Even on the Hawk forks you can't add it all at once and have to let it bleed the air out.

Did you cycle the fork at all when adding that 300ml? Did any air come out while pouring it in? I ask because if you try to pour in 200ml into a Hawk fork in one go without cycling it, it will fill really high and even overflow if the upper tube is all the way down. Yet once the system has the air bled out, there is a 170mm air gap with the tube all the way down.

I am sorry if I am seeming to not help. I am doing my best given the situation at hand.

[Duggo]

I think I have to fill the oil up in this space, which is going to require the syringe.

[Duggo]

I dumped the 300 in there before putting the retainer and nut on. Not the smartest move I've made today. So no, I didnt cycle it, it filled up the main chamber all the way to the top and onto the floor.

I see what you mean that I could pour in a little, let it drip down, add more, and it would take forever. I may still do that. I'm fed up for tonight I think.

Thanks for your help Dan. I realize you're kind of taking educated guesses on some of it. If it wasnt for you telling me about that nut and retainer, I would still be at step one.

You keep giving me ideas and Ill keep using them.

[Megadan]

Originally Posted by Duggo

I dumped the 300 in there before putting the retainer and nut on. Not the smartest move I've made today. So no, I didnt cycle it, it filled up the main chamber all the way to the top and onto the floor.

I see what you mean that I could pour in a little, let it drip down, add more, and it would take forever. I may still do that. I'm fed up for tonight I think.

Thanks for your help Dan. I realize you're kind of taking educated guesses on some of it. If it wasnt for you telling me about that nut and retainer, I would still be at step one.

You keep giving me ideas and Ill keep using them.

I am always good for ideas if nothing else. Believe me, I have had to learn some stuff through trial and error with the Hawk. Generally hurting my wallet more than anything lol. Experience is the greatest teacher! You should be a Guru of Storm forks by this is over with. I just want to learn everything I can from this as well for the next guy that comes along. Honestly if you were within a couple of hours from me I would offer to come and help figure that stuff out. It would be fun to do a long trip on the Hawk.

[Duggo]

Google maps says about 11 hours.

I just hope Napa has a syringe tomorrow. There is oil splattered all over my garage floor now and I hate that shit.

I was holding up the fork with my left hand and trying to open a valve deal with my right to get the oil in there. Needed a spare set of hands. It's all over the place now.

There is a motorsport place in town, maybe they would sell me the syringe deal, but Im sure it will be marked up 200%

[Its_not_a_honda]

I filled mine with 200 ml. Rode it. Bottomed out hard. I just kept filling until I got the ride I wanted. I think I ended with 245 ml. I loosened the top allen in the triple clamp. Then took the cap off and filled with 10 ml of 10 wt. fork oil. Each time bike was on a stand with forks fully extended.

This was very time consuming but worth it in the end.

[Duggo]

That makes sense, now that I have torn the thing apart. It would take a long time for that 10 ml to bubble down, then add 10 more, until you got what you were after.

Thanks for the info.

[Megadan]

Originally Posted by Its_not_a_honda

I filled mine with 200 ml. Rode it. Bottomed out hard. I just kept filling until I got the ride I wanted. I think I ended with 245 ml. I loosened the top allen in the triple clamp. Then took the cap off and filled with 10 ml of 10 wt. fork oil. Each time bike was on a stand with forks fully extended.

This was very time consuming but worth it in the end.

Kick ass! Great post and thank you for sharing!

[pete]

I used a bicycle pump to fill a car gear box once...
and those pump top lotion bottle also work...
slow but they do the job...



….

[Duggo]

Now that I've tossed and turned all night thinking about this damned thing, I think I know that 300 ml will fit. 300 put me right at the top of the main spring pipe, without adding that last section of pipe (see the assembly pics). 300 would put me right at that line, which is still too much I would think, but it would fit.

[goat67]

Hello
I can chime in here.

I changed the fork oil on my Brozz. I did not take anything apart other than the top, I drained out what I could and added 250 ml. I used ATF fluid.
I forget the brand but it was recommend here in some thread.

I am going to do this again as I am not happy with the amount of compression I get when braking, I am going to go with Maxima 20 wt fork oil.

I am not sure if I could add more than 250ml what would be the best way to determine if I can use more than 250ml?

[Duggo]

Look at the purple arrow on the picture of me holding the assembled fork.

300 will take you up to that line, a little more than that line. I'm going to test that out in 15 minutes when the auto store opens up.

You could fill it up into that pipe above the purple arrow if you want. That seems like a lot of compression and just doesn't seem logical too me. Because it's going to come out of the drain holes and always be over compressed, if that makes any sense.

Using heavier fork oil makes the most sense if you want stiffer.