S
Thought I would try to bring some of the useful topics from the old forum, frustrating work!
Snowhawk Suspension Question: The Holy Grail of 'Hawk handling?
Tue January 23, 2007
When was the last time anyone changed the oil in their forks? Any guess what color that stuff is(hint: it ain''t supposed to be BLACK!)
Unlike a motorcycle, our exhaust passes between the fork legs causing the oil to be exposed to additional heat. This heat could cause accellerated breakdown of our oil's dampening properties. Especially, as we stuff larger motors and pipes into our 'Hawk's belly and elevate the heat level between the 'legs.
I am changing my fork seals and this led me to think about the service life of fork oil in the 'Hawk. The '03 forks had never been apart and the sauce I poured out looked to be gear lube out of a 1903 tractor! This sludge can't be doing any good for the fork dampening and overall handling of my 'Hawk. It took a whole can of brake cleaner to get my base valves clean. Base valves are the stacks of flexible metal shims in the bottom of our fork tubes that control oil flow for compression dampening. It didnt take as much cleaner to get the rebound valves in the top ot the forks clean, but more oil stopping sludge came out of them as well. With no goo in the valves and fresh clean oil, the fork action was sooo smooth compared to before. At first, before I took every thing apart, when I pressed one tube on the floor, it felt squishy, almost pasty and slow to rebound. The other tube was slightly stickier than the first and squishy. After the service, both tubes pressed smoothly with equal resistance and rebound time.
I bet this difference has a dramatic effect on handling. Even more so where our 'Hawks can be weakest: bumpy trails.
Remember: Dirtbikes have wheels so they dont care about track geometry. If our forks compress and the rear suspension doesn't, the geometry changes, this changes the point of track contact from the flat of the skid to the front "approach angle" portion of the skid. Changing skid contact points changes handling characteristics because now, the horizontal skid shock is starting the upstroke dampening, instead of the upright skid shocks. In downhill bumps it is the worst because the rearend gets unweighted as the front fork gets weighted causing the most dramatic difference between the front and rear dampening positions. These small but signifcant things can make a smooth ride feel akward and uncertain.
Think of how nice it would be to have quality suspension feedback on that "one" off camber downhill left hander onto the narrow bridge crossing the creek, you know, the "one" that is always whooped nasty with braking bumps and no place to go, if you miss the bridge, but in the creek. To be able to ride through that section with the ski smoothly following the terrain providing predictable feedback for course corrections to stay on the line would be too easy. If your oil looks like mine did, I think you would be in for a rough and sketchy ride into the creek!
Do yer forks got fresh oil? How smoothly the fork can handle these transitions depends on if the fork oil is fresh and if the valves are clean, therefore, working at their maximin efficiency. Start the season with a fork service as opposed to ending the season with a fork service, that way the forks don't accumulate any oil contaminating condensation over the summer in storage.
Don't forget the little bleeder screws on the fork caps. The air in the forks should be "bled" or equalized with atmosphere before EVERY ride in order to keep air pressure from accumulating and blowing the seals. Fork bleeding is done by extending the fork all the way out, grabbing your knife and slashing... oh, wait, wrong subject... unscrewing the bleederscrew til the hissing stops(a second) then screw it back in again, repeat on other side. Lower the front end back down and ride!!
Thanks everyone for trying to follow my convoluted thought process. If someone has additional thoughts or experience or facts to ruin my flawed reasoning and make more sense of this subject, please, contribute!
YMMV and all that other stuff.
Is this a big job to do?-can it be done in my garage?Im an auto tech by trade with access to many tools-what type of specialized tools would I need or is this best left for the dealer- which is 3 hours away.
I rebuild my forks and rear suspension shocks every summer. It really makes a difference in performance and extends the life of your suspension.
Besides cleaner, seals and oil, the only "special" tools are the snap ring pliers for seal retaining ring, a large bore syringe w/ extention tube that can be marked for fork oil height-it sucks the excess oil out of the tube, and a "fork seal driver"(pvc pipe cut lengthwise in half to slam the new seal into the upper tube, this driver slides up and down the lower tube as it impacts the seal).
If only I could have said "it" this way. NOOOOO, I have to write a freaking book on the subject.
I changed the fork seals and oil on my '02 last week. Somebody used cottage cheese for fork oil. Weirdest thing. The other fork must have been an experiment as well. It had tapioca pudding in it. I'm pretty confident that it'll ride well this season.
Hey the same goes for your rear shocks also little bits of ice are shoved past the seals esspecially the lower front one w out the rubber gaurd so its flat amazing how much water they can accumulate so you should service these just as well each season cuz yuck same ugly black gunk is growing.
Very good read.
how often would you recommend changing the oil in the forks on a new hawk?
On the new 800 both rear shocks have the rubber protector on the top. how often would you say the rear would have to be done. how do you rebuild a rear shock? Once a season should be good enough, unlike our dirtbikes the environment is pretty clean so the oil stays clean longer. Try different weights/measurments of oil.
The seals on the early 503F's had weak springs, which leaked out and in.
We are working with Craig Bowman of CB Racing suspension specialists, Race Tech Certified, he is playing with one of our 2005 600HO short tracks.
360-425-4750
I am curious what Craig comes up with on that 600ST, he knows his way around a suspension bench. I bet he could get the shimming dialed in for powder vs. the hardpack it was setup for. Low speed vs High speed dampening curve? Or could it be the magical combination of both with the transition at just the right point in the travel of the 'Hawk.
Having a professional suspension tech do the services on our shocks means that the right tools and safety equipt are utilized and we don't accidently get fatal oil injections or cause a catastrophic gas release from the high pressure gas charge in the shocks. They also have the all important nitrogen cylinder with guaged needle next to their bench to recharge the shock when they are done. Another advantage to professional work is that they know what a worn or out-of-spec part looks like and can recommend replacement before there is greater damage done to the internals. I wouldn't know if my piston bushings were worn beyond their service life or if my valve shims were "bent" just by looking at them.
Snowhawk Suspension Question: The Holy Grail of 'Hawk handling?
Tue January 23, 2007
When was the last time anyone changed the oil in their forks? Any guess what color that stuff is(hint: it ain''t supposed to be BLACK!)
Unlike a motorcycle, our exhaust passes between the fork legs causing the oil to be exposed to additional heat. This heat could cause accellerated breakdown of our oil's dampening properties. Especially, as we stuff larger motors and pipes into our 'Hawk's belly and elevate the heat level between the 'legs.
I am changing my fork seals and this led me to think about the service life of fork oil in the 'Hawk. The '03 forks had never been apart and the sauce I poured out looked to be gear lube out of a 1903 tractor! This sludge can't be doing any good for the fork dampening and overall handling of my 'Hawk. It took a whole can of brake cleaner to get my base valves clean. Base valves are the stacks of flexible metal shims in the bottom of our fork tubes that control oil flow for compression dampening. It didnt take as much cleaner to get the rebound valves in the top ot the forks clean, but more oil stopping sludge came out of them as well. With no goo in the valves and fresh clean oil, the fork action was sooo smooth compared to before. At first, before I took every thing apart, when I pressed one tube on the floor, it felt squishy, almost pasty and slow to rebound. The other tube was slightly stickier than the first and squishy. After the service, both tubes pressed smoothly with equal resistance and rebound time.
I bet this difference has a dramatic effect on handling. Even more so where our 'Hawks can be weakest: bumpy trails.
Remember: Dirtbikes have wheels so they dont care about track geometry. If our forks compress and the rear suspension doesn't, the geometry changes, this changes the point of track contact from the flat of the skid to the front "approach angle" portion of the skid. Changing skid contact points changes handling characteristics because now, the horizontal skid shock is starting the upstroke dampening, instead of the upright skid shocks. In downhill bumps it is the worst because the rearend gets unweighted as the front fork gets weighted causing the most dramatic difference between the front and rear dampening positions. These small but signifcant things can make a smooth ride feel akward and uncertain.
Think of how nice it would be to have quality suspension feedback on that "one" off camber downhill left hander onto the narrow bridge crossing the creek, you know, the "one" that is always whooped nasty with braking bumps and no place to go, if you miss the bridge, but in the creek. To be able to ride through that section with the ski smoothly following the terrain providing predictable feedback for course corrections to stay on the line would be too easy. If your oil looks like mine did, I think you would be in for a rough and sketchy ride into the creek!
Do yer forks got fresh oil? How smoothly the fork can handle these transitions depends on if the fork oil is fresh and if the valves are clean, therefore, working at their maximin efficiency. Start the season with a fork service as opposed to ending the season with a fork service, that way the forks don't accumulate any oil contaminating condensation over the summer in storage.
Don't forget the little bleeder screws on the fork caps. The air in the forks should be "bled" or equalized with atmosphere before EVERY ride in order to keep air pressure from accumulating and blowing the seals. Fork bleeding is done by extending the fork all the way out, grabbing your knife and slashing... oh, wait, wrong subject... unscrewing the bleederscrew til the hissing stops(a second) then screw it back in again, repeat on other side. Lower the front end back down and ride!!
Thanks everyone for trying to follow my convoluted thought process. If someone has additional thoughts or experience or facts to ruin my flawed reasoning and make more sense of this subject, please, contribute!
YMMV and all that other stuff.
Is this a big job to do?-can it be done in my garage?Im an auto tech by trade with access to many tools-what type of specialized tools would I need or is this best left for the dealer- which is 3 hours away.
I rebuild my forks and rear suspension shocks every summer. It really makes a difference in performance and extends the life of your suspension.
Besides cleaner, seals and oil, the only "special" tools are the snap ring pliers for seal retaining ring, a large bore syringe w/ extention tube that can be marked for fork oil height-it sucks the excess oil out of the tube, and a "fork seal driver"(pvc pipe cut lengthwise in half to slam the new seal into the upper tube, this driver slides up and down the lower tube as it impacts the seal).
If only I could have said "it" this way. NOOOOO, I have to write a freaking book on the subject.
I changed the fork seals and oil on my '02 last week. Somebody used cottage cheese for fork oil. Weirdest thing. The other fork must have been an experiment as well. It had tapioca pudding in it. I'm pretty confident that it'll ride well this season.
Hey the same goes for your rear shocks also little bits of ice are shoved past the seals esspecially the lower front one w out the rubber gaurd so its flat amazing how much water they can accumulate so you should service these just as well each season cuz yuck same ugly black gunk is growing.
Very good read.
how often would you recommend changing the oil in the forks on a new hawk?
On the new 800 both rear shocks have the rubber protector on the top. how often would you say the rear would have to be done. how do you rebuild a rear shock? Once a season should be good enough, unlike our dirtbikes the environment is pretty clean so the oil stays clean longer. Try different weights/measurments of oil.
The seals on the early 503F's had weak springs, which leaked out and in.
We are working with Craig Bowman of CB Racing suspension specialists, Race Tech Certified, he is playing with one of our 2005 600HO short tracks.
360-425-4750
I am curious what Craig comes up with on that 600ST, he knows his way around a suspension bench. I bet he could get the shimming dialed in for powder vs. the hardpack it was setup for. Low speed vs High speed dampening curve? Or could it be the magical combination of both with the transition at just the right point in the travel of the 'Hawk.
Having a professional suspension tech do the services on our shocks means that the right tools and safety equipt are utilized and we don't accidently get fatal oil injections or cause a catastrophic gas release from the high pressure gas charge in the shocks. They also have the all important nitrogen cylinder with guaged needle next to their bench to recharge the shock when they are done. Another advantage to professional work is that they know what a worn or out-of-spec part looks like and can recommend replacement before there is greater damage done to the internals. I wouldn't know if my piston bushings were worn beyond their service life or if my valve shims were "bent" just by looking at them.
