conspiracy theory, fork oil answer

[scootscoot]

It's offical, no one on here has anymore credibility! I want to firm up my fork and saw that everyone on here says there is oil in the fork. So I recieved my service manual the other day and was browsing the fork section and it didn't mention anything about oil. Strange I thought, how could Honda have forgotten to put that in?? Or did Helm screw up? All it says is to add grease to X parts in the fork. So I took everything apart and low and behold there was no oil in the fork just grease. The fork can't hold oil anyways because there's a small hole at the bottom of each fork legs, and there is no oil seal at the sliders/stanchions just a dust seal. Now I'm thinking just get firmer springs or get another rubber stoper for the left leg also. This board is just a front so unsuspecting victims would spend $$ at the BSS..darn I just ordered a "edit profanity" load of stuff!!?

Oil is used for damping, cooling and lubrication in suspension. For oil to work for damping there needs to be valves or the like so the oil can flow through it. The Rucki forks are only simple spring frorks, no valves/etc. The good thing is that there is virtually no maintenance, but the bad is there is no damping. I believe the rear shock is also like this, that's why it feels so bad. At least there are rebound/negative travel springs which kind of suprise me for such a cheap fork. Normally cheap forks don't even have negative spings.

[Ruckass]

I havent taken apart my forks so I don't know what the inards are like. But if you think everyone on this site is somehow working for BSS and this whole site has just been set up to encourage people to buy parts from BSS, then explain why people sell things privately on this site or mention other parts shops and compare prices?

"This board is just a front so unsuspecting victims would spend $$ at the BSS..darn I just ordered a "edit profanity" load of stuff!!?"

That statement makes no sense. How does a chat board make people unsuspecting victims? Noone is forcing anyone to buy from BSS. Most people research a product on the net before they buy anyways and can figure out whats the best deal for them and their scoot. If you feel like you need someone to hold your hand before you make a purchase, maybe you should ask your mom to hold your credit card for you.

Ruckass

[Dandy Dan]

Interesting, I got my fork back in pieces from the dealer so I didn't get a chance to see what was in there for oil. Here's my thoughts:

Reasons why I think there's oil:
1) I have mine in pieces right now and I definately don't have "a small hole in the bottom of the fork legs". Even in a fork with no oil they wouldn't do this because water/junk would get in and damage/rust things.
2) There is a plastic cap on the bottom of the stanction tube (see pic in the 'fork disassembly' thread also in the 'Tuning' section.) This cap has some fancy holes around the perimeter which I presumed were to let the oil through. If there really is no oil why is this plastic cap called the 'slide pipe piston' and why does it have holes? No holes would prevent the top cap from blowing off.
3) My dealer told me there was oil and that it uses 5wt oil.
4) Abe said it uses oil

Reasons why I don't think there's oil:
1) It's not in the shop manual
2) As the fork compresses the air would get pressurized and thus would blow off the top caps as they are just wedged in the top. (This would happen regardless of whether there is oil or not but it would be more severe with oil cuz there would be less air to take up the same amount of compression so the PSI would be higher.)
3) ScootScoot didn't have any in his fork when he took it apart. Perhaps the hole in the fork leg he said he has, let the oil drain out. (unless, as I suspect, you were referring to the holes in the cap at the bottom of the stanchions/slider).

Regardless I'm gonna try running mine with some 10wt oil. I am gonna fill it up to just higher than the piston and see how it works. I do think it's entirely possible you are right scootscoot because it is an unusual design but I'm still not sure. Also, I thought my dealer lost it cuz he lost a bunch of other parts but the dealer ordered me a free rubber stopper which I'll use in the other fork leg. I suggest cutting this stoppers down to increase travel as they are unneccesary tall as explained in the 'fork disassembly thread'.

P.S. I think scootscoot was joking about the conspiracy thing. No one on here or at the BSS sells fork oil so the motive is a pretty vague correlation.

[lilruck]

I dont even think BSS sells fork oil or stock fork parts, so what do they have to gain by this fork conspiracy? Another thing is why would they want you to get better performance from a stock fork, when they are selling a those $1400. fork upgrade? If everyone could upgrade their stock forks do perform well they wouldn't have a market to sell those pricey Dio forks.That doesn't make sense. Actually, who is to say you dont work for BSS store and are trying to down the fork mod so word doesn't get out that they aren't the bad and you do have another option for better forks instead of $1400. forks. Even if you just spent alot of money at BSS dont worry about it, I just saved 15% on car insuarance.

[scootscoot]

DanDan, compress each leg and you will hear and feel air coming out at the bottom. If you're sure there is oil in the fork don't put anything under the fork legs to catch the oil and make sure you pour it in really fast! I dare you to take the pepsi challege. The stanchion tube doesn't hold anything, just empty air space, that's why it only has a plastic push on top cap. The bottom cap is just there for the spring to push against, and the holes don't do anything.

The spings are sooo soft that I can bottom out each leg by pushing on it. The rubber piece does firm up the fork that's why I'm gonna get another one for the left side, or get firmer spings. If you cut the rubber piece down it's not going to give you any more travel cause you only have as much travel as there is station tube expose, unless you cut down the guide bushing (like DanDan did). I don't recommend cutting the guide bushing(white plastic part that sits on top the negative spings) because you will mess up your negative travel, which is very important for quality travel. There will also be more flop(flex) cause of less over lap in the busing and stanchion/slider interface.

I just saved 15% on car insurance and slept at a holiday inn last night.

[Dandy Dan]

Air for sure doesn't come out the bottom of my fork legs. I tried what you said and I couldn't feel/hear anything so I wrapped my lips around the top of the empty fork tube sealing it at the top and blew as hard as I could. Nothing comes out for sure. Maybe the weld job at the bottom sealed mine but there's no way air comes out.

Cutting the rubber piece down DOES give you more travel. Here's why: the rubber piece is so stiff that it only compresses maybe 1/2 an inch but the spring could compress about 1.5" if there was no rubber piece. If the rubber piece was softer I would work ok but as is it is too stiff and limits your spring from becoming fully compressed.

Edit: When you say "The spings are sooo soft that I can bottom out each leg by pushing on it" what is happening is that you're running into the rubber stoppers which are so hard they barely compress. The stanction tube isn't going in all the way.

Quote from Scootscoot "I don't recommend cutting the guide bushing(white plastic part that sits on top the negative spings) because you will mess up your negative travel, which is very important for quality travel."

How does this mess up your negative travel? All it does is add 10mm or so of soft travel up top. Once the fork is compressed 10mm or more it would act the same as if you'd never done it. And anytime you're even leaning on the bike it is sitting atleast 10mm down. The only real advantage to this new found soft travel is an increase in negative travel which is useful for potholes etc. I would say this mod improves your negative travel because it adds about 50% more and would even make topout softer because the travel is weaker up top in that last little bit.

Quote: "There will also be more flop(flex) cause of less over lap in the busing and stanchion/slider interface."

Yeah but no. In theory yes because less overlap = more flex but in the real world the fork won't be riding up significantly higher because the travel is soft. Even it if would 10mm wouldn't produce a noticable difference.

I was looking at more fork more today and I am becoming more convinced all the time that it never did use oil.

[scootscoot]

It could be the welds..
If your fork can hold oil it still has no where to go but should feel firmer then my fork cause there will be pressure when it compresses.
Doesn't matter if there is the rubber or not, you can only get as much travel as there is expose stanchions. I'm already bottoming it out and I'm only 130#.

edit:
The non rubber side can easily be bottom out but not the rubber side. I think the stuff you poured out was water mixed with grease. Since you lost the top cap water got in and your fork apparently has no hole at the bottom so the water can't drain out.

As far as over lap goes..The bushing is very thick thus all the interface that the stachion has is the bushing ditto for the sliders. In high qulity forks the bushing is very thin so you pretty much have stanchions to slider interface

[Dandy Dan]

The rubber piece is 80mm tall (about 3") but the spring can compress to 44mm (1 3/4"). This means that the only way to get full use out of the stanchtions is to compress the rubber 36mm which is impossible under any normal circumstances. The rubber is really hard and I don't think you'd ever get more than 20mm of compression out of it under normal cirumstances (If the rubber really was soft enough to compress 36mm you wouldn't get the harsh bottom outs we get). This means that the rubber is stopping your stanction tubes about 60mm from the bottom of the fork legs when they could otherwise go down to 44mm so there is 16mm of travel to be gained. (If you do the math the rubber stopping things at 60mm tall gives you the exact travel Honda specs (56mm) so it should be right). Scootscoot, you said you can only get as much travel as there are exposed stanchtions and this is very true and important as you really don't want the part where the legs attach (crown?) running into your dust seals. According to my measurements a stock fork has 105mm sticking out of the stanchtions, of which 35mm is used up by the fork crown where the legs go into. This means you have 70mm of stanction tube available to be used. This means that a stock fork will never use the last 14mm of exposes stanction tubes. Shortening the rubber by 15mm should allow your fork to compress all the way down and thus would increase your travel. However, I realize that doing this does cut things close but if you were to shorten your rubber stopper(s) by 10mm you'd gain that 10mm in travel plus you'd have 4mm of clearance even if you still bottomed out plus the dust seals can compress a couple mm before they get damaged so it should be safe.

Using 2 stoppers as I will be instead of one like will be doing makes the rubber stopper effect even stiffer and thus the amount they will compress will be lower cuz there's two doing a one part job so you could cut them even shorter.

The exposed stanchtion tube amount is a very important thing to consider and thanks for pointing that out but I still believe there is room to add 10mm of travel safely and 15mm a little more dangerously. I cut off 15mm from my stoppers but I think I'll be safe because I'm adding the second stopper which should drop the amount they compress by atleast 5mm.

Personally, I think the best fork mod options are to shorten the rubber spacers 10mm and cut the preload down and somehow get stiffer springs. If you could find significantly stiffer springs you could almost get rid of the preload and add about an inch up top although your fork would ride a bit higher. You could also grind the top of the fork legs down a few mm if you really were serious about maximizing travel. The simplest and easiest mod would be if someone could find stiffer, compatable springs.

[scootscoot]

You can see how much travel you have left/are get form looking at the stanchions, mine went all the up against the fender. After putting everything back I hack up the stock fender and now my stachions are completely expose. As of now I have only 7mm to the bottom of the fork crown that isn't used. Wait until I bottom out the fork, going over 30 across railroad tracks, and I'll get back to you.

I think you're right about being able to cut down the rubber if you have two of them. You shouldn't worry about getting every last mm of travel out of this fork but getting quality travel. If you hack up the stuff that you suggested you'll lose quality travel. Negative travel is very import in getting better quality travel. Plus you get extra flex with less stachion to bushing to slider over lap.

With all these extra mm you are getting you are forgetting about suspension sag, which actually determins how firm your springs needs to be. On road you'll want about 20% sag in the riding postion. This means that your fork should compress 20% with you on the bike, use a zip tie on the stanchion to detimine this. I bet you will still get the same amout of travel you had before despite hacking up stuff, because you still weight the same and the springs are still the same. With you on the bike the fork will still compress to the same postion as before you hacked everything. Now if you had firmer springs then you'll get more travel cause you'll be riding a little higher up cause you'll have less sag.

You actually will end up with more negative travel now, in a way that sort of gives you more positive travel. When say going over rough surface and there is a dip the wheel will extend that extra amount of travel, that you got from hacking up the fork, into the dip. Now that the fork is top out, fork fully extended, with the wheel in the dip this is when you will get your extra travel. By the way this is the reason why negative travel is important, and so you don't get a harsh top out. Because of sag you will only get so much positive travel especially when on smooth surface.

If a fork only has 100mm of positive travel and 10mm of negative travel and you ideally have 20% sag. You will be riding with 80mm of travel left. If you hit a dip and make the fork top out you will end up with 110mm of travel, but if you hit a bump you'll only have 80mm. Once your wheel passes the peak of the bump and extends back, this is also where negative travel comes in, it'll go back to it was before the bump; negative travel just makes this transtion feel better.

The best thing to do with this fork is getting spings that will give you the recommended sag and another rubber so you don't bottom out since it doesn't have any type of damping.

Since we don't have a suspension guru on here, I should write up a tech section on the subject. I'll do it when I have time.

[chanito]

Wow! this is a great post, and is true in the manual they do not mention any fluid at all on the front fork, now scootscoot if you know a good suspension guru, i can get him some work really quick, now back to business, the front suspension, and any kind of suspension for that matter, job is to keep the wheel touching the ground all the time, when you encounter a bump on the road the suspension goes up, and that send a shock thru the bike, then the wheel keep keeps going up until it is not touching the ground any more (so that wheel is not doing any work in controlling the vehicle), after that it will fall back to ground giving you another shock, now if you encounter a dip the vehicle will fall into it, until it hits the bottom, then this bottom will behave as a bump, starting the above process, complicated by the inertia of the vehicle going down, someone a long time ago decided to solve this problem by using spring, and they do a great job of softening the blows and to keep the wheels on the ground, the problem is spring have a tendency to oscillate, which is the ability to keep moving, when the reason to move is not longer there, this creates a seasickness on the rider, to control this problem, someone else created shock absorbers, and a lot of different people solve this problem with different solutions, the solution for our bikes is the tube shock absorber, now tube shock absorbers use some kind of fluid trapped in two (or more) communicating chambers, so with the movement one will empty and the other will fill there is a valve which control the speed at what this transfer of fluid takes place, most tube shock absorbers use oil (which is fine) but oil is very linear when it flows so it moves as fast at the beginning as at the end, gas on the other hand is more friendly so it moves fast at the beginning and slows down at the end (fast equal soft, slow equal hard) therefore getting a more pleasant suspension, the preferred gas is nitrogen, because its pressure is not affected by heat (well it is, but you need a LOT of heat), but you can forget about that for our scooters because it is way expensive, any way back to topic. the need for shock absorbers is dictated in great portion by mass (how heavy something is) the heavier the more inertia the more this undesired oscillations would be, luckily for us the front of our scooter is very light, plus the unsuspended weight is super low (the part between the ground and your spring) this is very important because that is where for inertia will came from, so in theory we can get away with shock absorbers altogether, so that is why we might not have any oil in the front forks (or very little just to lubricate, and make the springs act quietly), however as it has been stated before since i never taken any front shock from a scooter before, i am not sure, having an "open" hole in the bottom of the shock is a terrible idea because as DD said it will allow moisture and dirt free roam of the shock, not good, on the other hand it is great to have as much free travel as you can, but is way more important to have control travel ( i hope you guys are still with me), the reason for the preload is to have instant response to transient travel (from nice pavement to dips or bumps) to prevent shocks, so actually is a compromise between travel and comfort, in my point of view i would want more preload (but i weight 225 lbs, or 102 kilos), but for some maybe more travel would be nice. Now i need to take apart my front forks to get to the bottom of this.
And i also expect scootscoot to do a nice tech on this subject, because i am not suspension guru

[lilruck]

Does the manual tell you how much torque those four bolts that hold the forks on need. My Forks were not on my Ruckus when I got it and I just bolted them on and haven't gotten a manual yet. Thanks

[chanito]

No it does not, just said to tighten pinch bolts securelly

[scootscoot]

When a vehicle encounters a dip what should happen if you have ideal situation is not the vehicle going into the dip then the fork works but the wheels should go into the dip and the vehicle stays in the same position (this is what negative travel is for). This only hold true if the bump or dip is within the travel range of the suspension and you have good suspension. Watch a video of off road riding (motorcross, DH mtb, whatever) you will see that for the most part the rider and the bike will stay relatively level with the terrain while the wheels are bounching mad, and when the bumps are beyond the the travel range of the suspension the bike will move then the riders arms and legs act as suspension and the rider's body still stays constant relative to the terrain.

Telescoping forks are the best design overall, it's tried and true. For forks only oil is used for damping not gas as far as I know. Gas, nitrogen, is used in rear shocks as well as oil, not sure of our rear shock. On street I've never encouter heat issues with suspension but offroad in technical terrain heat effects happens occassionally.

Our forks don't have any oil cause of economic reasons.

[Dandy Dan]

Well this has been an informative thread. Here are my conclusions:

1) The fork doesn't use oil. (Scootscoot, I didn't actually take mine apart, the dealer did and gave it back to me in pieces so I never got to see what was in there although a water/grease mix is a likely guess). Thanks for this info scootscoot.

2) I undertand what you said scootscoot about the bushing being the interface between the legs and the stanchtion and shortening this compromises the rigidity. I agree that this would make a difference but there is also about 25mm of overlap with the bottom cap on the stanchtion. The bushing height does matter but I think a larger factor for rigidity is the distance between the bushing and the lower cap. What I mean is, 1 inch of interface with a 5 inch gap and then another 1 inch of interface will be way stronger than say just 3 consecutive inches of interface even though the actual surface area contract is smaller. Shortening the bushing 10mm does drop this distance (between bushing and lower cap) and so you're right that it does weaken things. I agree with everything you said but I don't think the difference will be noticable or significant.

3) Two rubber stoppers might be a bad idea as bottom outs would be even harsher. I'm thinking about shortening the one I've got coming by 5-10mm to be totally safe with respect to the crown hitting the dust seals and just tossing the other one I cut 15mm off of.

4) Regarding negative travel. I think we all understand what it does so I won't share my thoughts. The only thing I want to say is that I don't think shortening the bushings will mess it up. The fork sag will easily use up way more than the new 10m of travel so I don't think it would have any effect on normal hits. The riders weight adds preload to the fork and this preload is greater than what the bushing puts on there so the actual amount of preload the bushing causes seem insignificant. The only difference I see is that it would add about 50% negative travel and because the main springs would be less compressed when the fork tops out it seems to me like top outs would be less harsh than before.

I'm still trying to figure out why there are holes in the 'piston' cap on the lower end of the stanchtion tube. They could just be there as part of the manufacturing process caused when they punch out the little legs that clip into the stanchion. This still seams like a poor design because the air pressure would ramp up inside the stanchtion and push on the cheap top cap which is likely what caused mine to blow off (well it probably was a bit loose and that didn't help). I think filling this holes with something (superglue? i dunno...) might be worth doing if you're in there anyways. I'm actually thinking about modifying a damping system into my fork. Here's what I'm thinking, (I'd value your input): Drill out the holes a bit bigger or just drill new ones. Also, I'd ensure the bottom has a proper seal on both legs (I'd like some more opinions on whether other peoples fork legs have holes in them. One of our forks is odd). Then I'd need to prevent the top cap from blowing off so I'm thinking I'd weld a round disc into the top of the stanchtion so the plastic cap would just be for eye candy (I'd weld it 1/2" down so it wouldn't mess up the stock cap). Then I'd fill it up with 10wt oil so at rest it would fill the fork up to just above the newly modified piston (lower stanchion cap). I'd only do this in one leg as that would likely be enough. Your thoughts? The plastic piston is like a 4$ part and shouldn't even be wrecked if the system sucks and I could drill the welded cap out of the stanchtion if I wanted although leaving it there wouldn't really cause any harm. I'd doesn't seem like I could really loose even if it is terrible.

Edit: I bet this thread wins for longest average post length. With the exception of a couple one liners almost all the posts are essays.

[scootscoot]

DanDan, before you cut up the new rubber piece try it out first and see if your dust caps reach the bottom of the fork crown. Two rubber at full lenght would be too harsh towards the bottom half of travel but if they where cut down a little I think it would work out better. Now how much to cut down depends on your weight and guesstimation.

You can try that oil thing but the holes don't need to be very large, try'em as is first then go from there. Don't wasting your time welding the stanchion top, you'll need some place to relieve the pressure build up since these forks don't have oil seals, it might squirt oil out your dust cap.

Our post are pretty long but I hope people will find this tread informative and not too confusing.

[Dandy Dan]

I will (try it without cutting the rubber). I'll see how close I can get it and then add some safety margin cuz I won't be able to simulate a large pothole hit and if I still think there's room to add more travel I'll do so.

Have you tried compressing your fork without the main springs in and just pushing on the rubbers? They really don't have much give. Maybe 1/2" under normal circumstances. Two full length rubbers would just be cruel on ones wrists. Perhaps two with one shorter than the other so it ramps up more gradually. I'll have to play around a bit.

Good point on the dust seals not being to handle the pressure. Are you suggesting I don't run with the stock top cap? I kinda want to because I ride in the rain and don't want dust etc. gettin the oil. Perhaps I could drill a small hole in the top cap to relieve the airpressure. I'm curious how much the dust seals suck because they don't look extremely cheap. I think they could handle minor airpressure. I agree that I do need someplace to relieve the pressure as I would blow through the dust seals if I seal the stanchtion tube. Can you think of a better idea than a small drilled hole (1/8"??) in the top cap? Then I could just replace the oil every few mths and it shouldn't get to gross.

[scootscoot]

Yeah, I think the easiest way is to drill a tiny hole in the top cap. Trying to compress the rubber side by hand is pretty hard but when riding at 30+mph over RR tracks or large pot hole the fork will easily give.

[chanito]

When i stated that a vehicle falls into a dip and jumps in a bump i was explaining the dynamics of a vehicle so people will understand the need for a suspension, obviously a good working suspension would isolate the vehicle from dips and bumps, but anyway i think you and DD have it all figure out

[scootscoot]

Bottom out with ~8mm of stanchion left, I think that's the height of the fender. DanDan can you check the height of the fender if your fork is still apart, I've choped mine up and toss out the stanchion part of the fender already.

[Dandy Dan]

I actually just put mine together today. I think is was about 4mm but that's a guess. Anyways, here's what I've learned lately,

1) There's no way to put an oil damping system in. The seals just are so weak the oil blows out of there like it's nothing
2) Scootscoot, your right when you say you don't really want the fork compressing more than it does stock. There's a bit of stanchion left but not much so it's not really worth the hassle or risk
3) You can add a bit of travel by cutting the bushing from 30mm to 20mm and then taking that 10mm bushing (or any other spacer) and putting it under the spring. If you just cut the bushing the new found travel is really soft and is almost useless but adding back the preload to the spring by putting a spacer under it that doesn't interfere with the rubber stopper will get you the preload back. Note: Doing this will decrease the ridigity of your fork slightly.
4) Lastly, you could stiffen things up a bit by just adding preload under the spring, with a compressed height of 44mm and the rubber stopper having a non compressed height of 80mm and maybe 60 compressed, there is some room to add more preload without losing any travel. Make sure you don't just stick a spacer at the bottom of the leg cuz if it lifts the rubber up too then you've just shortened your travel for no gain. You need a Cheerio shaped piece so the rubber isn't lifted up.