PVC in Forks ??

[Derrick Adams]

When you put the PVC in the front forks, where do you put it? At the top or the bottom of the forks?

What is the limit or best length? 1"-2"?

[Billy Golightly]

I've got 2.5 inches on top of my progressive springs in the Z Derrick. They were a little bit hard to get compressed and get the cap screwed down. Easier with 2 people.

[twgranger]

I used washers in mine. The cap is hell getting back on.

[brapp]

ok what you can do is measure the freelength between the coils in the springs. thats your free travel. you want to go 1/8th of that maximum. and inother thing possible is cut a small section out of somethign stiffer liek a steel pipe or i have made aluminum chunks already. but pvc also works and they go up top near the fork caps. it stiffens them up fairly well.

[TimSr]

With what springs? If you go with progressive springs, youll want the full length of the PVC spacers that come with the springs for your weight. I think they were like 2 1/2". They go on top of the springs. If you are trying to bandaid sagging stockers, again, for YOUR weight, go with 3" if you can get that much in there.

This is not an across the board recommendation. Derrick is a very big guy, and likes being airbourne.

[Derrick Adams]

3" of PVC is installed. All I can say is WOW! I changed my seals, put in some 20w fork oil and installed the PVC and now I want to go jump something! It feels so much better already.

Now we'll see if the fork seals leak or not.

[Billy Golightly]

Derrick did you use OEM or the ones from Dennis Kirk? I have not had good luck with the ones from Dennis Kirk in my Z. I did just put a pair in the 250R forks on the 500 and so far so good with those.

[Derrick Adams]

I used the Vesrah ones. We'll see how it works out.

[TimSr]

Hey Derrick, check out Pitracer.com and look up a practice MX track near you!

[OldSchoolin86]

Great tip, I just put 1-1/4" PVC spacers in my R forks and love it. Thanks

[Derrick Adams]

Yeah, very suprising. Although 3" is too much. I could barely move the forks with all my weight!

[OldSchoolin86]

Are you making these spacers? I use a lot of this material so I just went out and cut mine. Maybe for TF06 I could cut up a bunch of them for door prizes if you think they are worth anything.

[Mr. Sandman]

What diameter PVC do you use?

[OldSchoolin86]

What diameter PVC do you use?
I used 1" SCH80 PVC and it fit perfect!

[nouseforaname90]

You just take off the hex-head fork cap, put it in, and close it back up??
Also.. how high should the oil be in the fork?

[Mr. Sandman]

You just take off the hex-head fork cap, put it in, and close it back up??
Also.. how high should the oil be in the fork?
You should measure and fill according to the manufacturer's recommendations. Less oil would be ok, but be careful with more, or experiment with different weight oils.

On another note, although minimal, because of the oil contact with the typical white irrigation PVC, it might be wise to use the gray electrical PVC which is UV and oil/chemical resistant, if you're not already.

[nouseforaname90]

What would the oil do to the PVC? Doesn't really seem like the oil would harm it..

[Mr. Sandman]

What would the oil do to the PVC? Doesn't really seem like the oil would harm it..
It depends on how much contact the PVC has with oil, but eventually it'll soften and deform. Sunlight or UV rays will yellow it and cause it to turn brittle.

But, if you have UV rays inside your forks, you've got bigger problems than sagging springs and no amount of PVC wil help.
;)

[TimSr]

When I bought my progressive springs through Dennis Kirk they were shipped with two white PVC spacers in the box, and the installation instructions told about cutting them to the appropriate length for the rider's weight. I cant imagine oil breaking them down, or I dont think they would ship them with the springs. Ive had mine for a few years now.