Author Topic: fork settings (Read 3041 times)

musturbo · « **on:** May 20, 2005, 10:55:50 AM »

I noticed riding today if I get into heavy bumps the front will go into a violent high speed wobble. Not fun at 50 mph. Couldn't find anyhting loose, fine on the regulat terrain. Just going thru the rough stuff. Guessing it is my genius in suspension tuning. Help!

KXcam22 · « **Reply #1 on:** May 20, 2005, 04:10:48 PM »

Musturbo,
I think either a touch too much compression damping, or too much spring preload (if there is any). Basically with the power on over rough stuff with your weight back (not much weight on the forks) the forks ricochette off stuff instead of absorbing with the first few inches of travel. Does that sound familiar? Hope this helps. Cam.

musturbo · « **Reply #2 on:** May 21, 2005, 02:23:46 AM »

That is exactly what happened. Thanks man.

GDubb · « **Reply #3 on:** May 22, 2005, 06:56:26 AM »

My bike does the same thing when I go wide open across the flats at the dunes... so far I just put my weight as far back as I can and pull back harder on the bars, but when I let off the throttle and the front end gets heavier it can get pretty scary. Sounds like what you are talking about Cam... can I fix this with the adjustments? or do I need to consider springs and valves? I weigh right at 170 so I think the stock set-up should work for me... hopefully just adjustments then? More notes... it handles the whoops fine, the faster the better, and have never noticed a hard bottom-out on big landings. Any advice is much appreciated. Suspension baffles me for some reason, so unless I can get some specific instructions(which I know is hard to do over the computer) I just leave it alone.

KXcam22 · « **Reply #4 on:** May 22, 2005, 05:39:46 PM »

GDubb,
Are you running the stock fork springs? They might be a touch soft but you should be able to tune it with the clickers and oil level. I tend to run my compression damping a touch soft (better for rough trails and general riding) and increase the oil level to stop any bottoming. Increasing the oil level simply reduces the total amount of air in the fork. The smaller air volume compresses faster and adds a rising rate to boost the fork spring. This only acts in about the last 3" of travel. If you like whoops you might like them even more with a bit stiffer fork springs. Helps stabilty in the whoops too. Hope this helps. Cam.

Brett · « **Reply #5 on:** May 22, 2005, 11:12:33 PM »

I weigh 60kg (130lb) and have the same problem as gdubb in that in the soft sand the front end ploughs when not giving it enough noise. How do you measure and adjust the fork level? do you just open up the bleed and measure down with the bottom of a vernier calliper?

KXcam22 · « **Reply #6 on:** May 23, 2005, 04:53:25 PM »

Brett,
It's quite easy. Take off the bars and remove the fork caps and springs. Compress the fork fully ( On a stand I use tie downs to hold the front wheel up). The oil level is measured oil surface to top edge of the fork. Buy yourself a cheap turkey baster (those syringe things) and mark from 0cm (tip) to 120cm on the side. I just filed marks and wrote with a felt pen. Overfill the fork a touch and then slide the baster in to the right marking and suck out the extra oil to get the right level. Cam.

Brett · « **Reply #7 on:** May 24, 2005, 11:38:20 PM »

Sounds easy, i spose you would require the forks to be vertical. Is there any chart available to work out what springs i have for front and back?

KXcam22 · « **Reply #8 on:** May 25, 2005, 02:03:35 AM »

Brett,
As long as the tip of the turkey baster (or whaterver you suck the excess oil out with) is roughly in the center of the fork the angle doesn't matter too much. You can always tip your bike on the stand till the front wheel touches the ground. Race Tech has a good site for showing you what springs you should have. As for the ones on there, if they are not stock then it can be hard to tell. Cam.