Fork Mod opinions

[discgolfer2711]

This site has been an awesome source so far. You guys no your stuff. So far I got my rear spring pre-load set to 7 (an amazing difference ) & fixed my oil leak from the shifter seal. I have had the bike for about 6 months and 3000+ miles I've been really happy with the bike. With the exception that the front fork bottoms out too often and generally is too soft.

I saw a how-to about modding the front fork with some PVC spacers on the site. Is it safe?

The easy answer would be to upgrade the fork, but don't really have the cash for that kind of thing.

Just curious if anyone has done this. Thoughts?

Thanks

[Bluehaze]

Before you do anything with spacers, I believe your best bet is to change the fork oil to something heavier.  start with 15w...  you will most definitely feel a dfiiference.  You may even go up to 20w. but start with 15w first.  its a 10dollar upgrade.  if you are here in US.   

[ineedanap]

I'm with bluehaze 100%.  Heck it's routine maintainance anyway and easy to justify.   You might not be too happy with adding lots of preload with spacers, though.  

Springs are goofy and the results of bumping the preload way up on stock springs might not give you what you expect.  

Most springs have a fixed rate.  Lets say 100lbs per inch.  So, for the first inch takes 100lbs to compress.  The second inch takes another 100 lbs to compress an inch and a total of lets say 400 lbs total to bottom out at 4 inches.  

Adding a crapload of preload to a soft fork spring can make for an interesting ride.  Example... on the stock spring above with a crapload of preload would be 300lbs for the first inch, but since springs are a fixed rate it would only take 100 more lbs for the next inch,  and a total of only 600 lbs to bottom out at 4 inches.  The worst of both worlds, way way way too firm where you want it soft, and still relatively soft where you want it firm.  

Sorry to type so much,  I'm bored.

[Bluesmudge]

Preload only really makes a difference when the springs are not under load. If you want a real improvement, do what bluehaze suggested and get heavier fork oil to change the dampening of the forks.

[lamoun]

You should preload it enough to set your sag properly.

As for the oil, it will make the fork to move a bit slower and it might help.
If you go for this then add some more oil than Suzuki comments and test.
At the end of the fork travel, the amount of air between oil and the cap, acts as an additional progressive spring. Adding oil you make the air-spring appear faster.

[dohabee]

If you add more oil could it cause the seals to fail?

I'm just thinking that the pressure would be higher when you bottom out but im not sure

[joker79507]

Get some new front springs.  I went with .85 sonic springs and am happy with them.

[discgolfer2711]

I searched the forums last night some more. It seems that switching to progressive springs and switching to 15w oil a good option. I'm not planning on modding this bike too much though, so I'll probably stick to changing the forks oil to 15 weight. Like I tell my friends, if I had an extra 300 for an exhaust or multitude of other mods, I would rather just pay the bike loan down some more.

I tried searching the forums for a "how to" on just replacing the fluid. Does the clymer manual explain it well?

[joker79507]

The "right" way to do it is to remove each fork while supporting the bike with a jack or something, then turn the tubes upside down and dump all the fluid.  Realistically it wont remove all the fluid unless you give it a good cleaning and let it dry (read:time consuming).  There is a lazy mans way to remove old fluid in the wiki.  Just use tubbing with a large syringe, or something similar to suck the old fluid out, and then pour in the new fluid.  Someone else can chime in on whether that will affect him any, having a little of the lighter weight oil in there...in my oppinion it would eventually make its way to the top because it is a lighter weight and then you could suck the rest of it out, but thats just a theory, never tried it before. 

I know you dont want to spend much money on this bike but the springs are just around 100 including shipping, if i remember correctly, and they will make you enjoy the bike that much more.  Just my opinion though.

[scratch]

http://www.peterverdonedesigns.com/introduction.htm

http://gstwins.com/gsboard/index.php?topic=27361.0

[jrains89]

before you spend a ton of money, spend 20 minutes and put new 20w fork oil in your forks. hardest part was sucking out all the old oil until we rigged up a vacuum.  seriously i never bottom out anymore and am very happy with the 18 dollars i spent versus 100 ish for everything if i had gone the spring round. if you're not going to be racing this thing i think 20w is good enough.

[wlaroche]

When you change the oil weight, you change the rate that the fork will deflect. This works both ways down and up. Has anyone seen a problem with the tire coming off the ground and not rebounding quick enough making the handleing a little squirly? I am weigh 190 and can bottom out the fork quite easily. I am thinking of adding spacers, progressive springs and/or different oil in some combination.

[VSG]

I'm about 190 and went with progressive springs and 15W fork oil.  I'm very happy with the results.

[The Buddha]

If you add more oil could it cause the seals to fail?

I'm just thinking that the pressure would be higher when you bottom out but im not sure

Oh yes it will ... but thicker weight oil will not. Thicker oil only is a measurement of the resistance to flowing.

Like our old perpetual motion theory in eng school.
Suck fluid out of a container to a high platform, then let it run back into that same container while turning a wheel.

When will you make enough electricity in the wheel to cover the electricity used by the suction pump.

You know, I am sorry - that has to be a basic question to be posed to any clown who wants to run for president.

"I am sorry, my advisors will take care of that" ... and then these 2 CIA thugs beat you up ...

Anyway, one of the conditions is that it should have pumping resistance of 0 - AKA - coefficient of viscosity = 0 - was it lambda ? I cant quite remember.

The largest loss though in practical circumstances for that type of setup is velocity of the liquid as it drops into the container - that has to be 0. So should evaporation loss in transit.

Cool.
Buddha.

[JB848]

Um ok can some one translate and bring the real Buddha back?