Boy, was that ever fun.

[JeffL]

Just replaced the fork springs and oil in my bike. Have no idea if I did it right, and made a hell of a mess doing it, but its done nonetheless.

Good thing I have no idea what a good suspension feels like, otherwise I might be disappointed the first time I ride it.

Is fork oil nasty stuff like brake fluid? I mean, if I were to have gotten it all over the place (which I most certainly didnt. ), is it going to eat the paint off my plastics and wreak all havoc, or what?

[Currently]

Nah ... just oil

My SV had something that looked like, smelled like and felt like automatic transmission fluid.

I put the Bel Ray into it with the springs and emulators and made a big difference.

Now I got me another set of forks on it.

[JeffL]

I ended up using Motorex 15w oil and .80kg Race Tech springs, in place of the .43kg stock springs, and 5w oil I believe? Used the Motorex because it was the only 15w fork oil they had from where I ordered the springs.

I used the instructions on how to set the sag using a formula measuring a bunch of distances in the fork with the spring installed/cap height/washer thickness, whatever, but I think my sag is fucked beyond all belief. The bike doesnt sink nearly as much as it did before, but using their method of measuring sag, I dont think its even close to the "desired" 30mm I chose to try.

Regardless, the bike will handle immensely different now, I'll pretty much have to relearn to ride.

[gmdboston]

Jeff, did it take two men and a boy to get the caps back on? When you assemble a fork like your's the cap should be about flush with the top of the tube and thread in by hand until you get to the O-ring on the top of the cap. The total pre-load on a fork spring should be 10-15mm when you finish threading the caps on, so you were looking at any spring or spacer before you start the threading the cap in you have too much pre-load.

The bike should settle 22-25mm under it's own weight (free sag) and a total of 30-40mm with you on it. If you have too much pre-load and the bike stays at or close to top out, it will shake violently when you ride it. Make sure you get it right, or go back to stock.

[Tricky Mike]

Originally posted by gmdboston
If you have too much pre-load and the bike stays at or close to top out, it will shake violently when you ride it.

That sounds like a good time

[JeffL]

With the forks fully extended, to the sag height with me on it, I was getting 55mm, and the bike was settling about 20-25mm I believe under its own weight? That sound about right?

Basically the race tech instructions stated that cutting the spacer to the distance between the cap and the spring, with the forks completely unloaded would = 0 preload, and to simply add my desired preload on top of that. Was shooting for 30mm, so I had a 0 preload length of 147mm, so cut my spacer to 177mm.

It took me both hands and good amount of effort to press the caps back on and started threading. I had probably 1-1.5" of spacer showing out the top of the fork tube.

[JeffL]

In retrospect, I probably should have made some attempt at measuring my ride height and rake, so I dont have to COMPLETELY relearn steering the bike. I know the ride height went up, so I'll have to remember my steering wont be as quick as it was.

[JeffL]

Got ahold of Peter Kates, I was way off.

Way overloaded the preload, front end was just a pogostick. I knew something was wrong the first time I hit the brakes at the end of my road. Basically there was no amount of damping I could put in the front end to try and control the spring, so it just bounced/stuttered until I came to a stop.

Not much I can do about the sag, its gonna be what its gonna be, until I start a)putting money into these forks, or b)just swapping on forks from another bike.

Oh well, should still be an improvement over stock.

Thanks for the help Peter, grabbing a little grub, and heading back out to the garage to rectify the issue. Will see you guys Tuesday.

[JeffL]

I give up. I messed up a bit yesterday with the spacers, got that taken care of today, now, pfftt.

My spacers were about 20mm too short, so I effectively had 0mm of preload on the spring. Ok, got that fixed, double checked the oil level, good to go.

Take it out for a quick spin......its better, but by no means great. Under hard braking, the front still chatters for a second before settling in. I'll get maybe 2-3 really quick bounces, and then it "somewhat" smoothes out, but not quite.

Is this just a damping problem now? Should I slowly add oil till I get the desired effect? Or do I want less oil?

I want to slam my head against a wall, especially with the trackday next tuesday, and I have no time to work on the bike/ride it to test it out. I've got a few hours sunday morning/afternoon,but thats it.