[kidwoo]

I've got an 03 firefly that I put some spacers in and changed the spring to drop the travel to a permanant 90mm for my jump bike and the dampers don't seem to work. I've got the stiffest spring available in there so I'd expect more stress on the damper. But I've put 20wt oil in there and the damper(s) doesn't do anything at all. I never touched the damper side when I did the travel mod.

Is there something about the damper that it doesn't or won't engage since it sits lower in its travel now. It seemed to work okay before I screwed around with the spring side.

The compression damper is on the top, so I saw this piece when I put in the heavier oil. I'm assuming the rebound stack is the same. Pretty much a shim-style with some lockrings and a rubber gasket.

Any ideas?

 

[Kornphlake]

I think the TPC + system uses a stepped cylinder the piston runs through so that oil can flow around the piston when it's in the initial part of the travel giving a plush feeling, once you push the damper past the step the piston fits tightly in the cylinder and forces the oil to pass through the piston. lowering the fork might have made it so the piston is always in the reigon where oil can flow around the piston making it feel like there's no damping.

Then again I could be totally wrong on how the damper is designed and what it really does. The one TPC fork I owned did blow up at one point, the compression damping was always very sensitive, I could go from pogo stick to lock out with just a few turns of the compression adjuster knob, then one day it was full time pogo stick no matter how much I turned the knob. I took it apart and saw nothing unusual the put it back together with fresh oil without any perceptible change in performance. I ended up selling the fork on eBay the way it was, I wish I could have figured out what was wrong with it though, my concience still eats me up for not disclosing the blown compression damping and the buyer seems to have never noticed there was anything wrong.

 

[dfinn]

...my concience still eats me up for not disclosing the blown compression damping and the buyer seems to have never noticed there was anything wrong.

note to self, never buy anything from Kornphlake

 

[kidwoo]

lowering the fork might have made it so the piston is always in the reigon where oil can flow around the piston making it feel like there's no damping..

That's kind of what I was thinking.

then one day it was full time pogo stick no matter how much I turned the knob. .

Bingo.

my concience still eats me up for not disclosing the blown compression damping and the buyer seems to have never noticed there was anything wrong.

Note to self: Never buy anything from Kornphlake.

 

[kidwoo]

boomp

 

[thaflyinfatman]

I got a brand new 05 Flick+ a couple of weeks ago, and I'm convinced the compression adjuster does nothing. It has the TPC damping (not TPC+) if that would make any difference - ideas? I haven't pulled it to bits yet, might have to do that soon.

 

[MisterMental]

is it me or is 20wt oil too heavy for the tpc cart.? they run on 5 standard dont they? souldnt 10 be a better weight to start with?

 

[vitox]

kornphlake:


the tpc+ is a piston with two valves on it, the first one is at a fixed height (upper piston) and the lower one slides up and down the piston shaft with a spring to help it back to its original position at the lower end of the rod, as you compress the fork the oil pressure presses the lower valve up until it hits the upper valve and from there on you have more compression damping. this is not too far from the SPV system but thats another story altogether.


kidwoo:

try with 5wt see what happens, maybe that marmelade you have in there now doesnt let the rebound valve to close or something freak like that.

 

[vitox]

Then again I could be totally wrong on how the damper is designed and what it really does. The one TPC fork I owned did blow up at one point, the compression damping was always very sensitive, I could go from pogo stick to lock out with just a few turns of the compression adjuster knob, then one day it was full time pogo stick no matter how much I turned the knob. I took it apart and saw nothing unusual the put it back together with fresh oil without any perceptible change in performance. I ended up selling the fork on eBay the way it was, I wish I could have figured out what was wrong with it though, my concience still eats me up for not disclosing the blown compression damping and the buyer seems to have never noticed there was anything wrong.

id take a wild guess at a broken shim being the culprit (just a tiny bit of breakage to the one closest to the valve core will do just what you describe)

 

[kidwoo]

kornphlake:

kidwoo:

try with 5wt see what happens, maybe that marmelade you have in there now doesnt let the rebound valve to close or something freak like that.

I did. Before I dumped the sludge in there I changed the oil that was in there, mostly just to check levels and used 5wt.

The only reason I put 20wt in there was to create an extreme case in the event that the damper was overwhelmed with the really high spring rate. I figured if the damper did nothing with 5wt but was functioning properly, I would see a really dramatic amount of damping with the 20.....and I would know the damper is at least doing its thing.

There was no change at all in behavior between the 5 and 20wt which makes me think position of the damper rod may have something to do with it.

I've had these things apart before but not in the last 2 years.....thanks for the refresher. It helps visualization.

 

[MisterMental]

i would have thought 20 would be far too thick but if you say youve tryed 5 and theres no difference then it would be a bit broken then wouldnt it

 

[Orvan]

I wonder why Manitou did not just retain the Dorado TPC+ cartridge and its range in both rebound and compression on ALL TPC+ fork line-up. The TPC+ in the Dorado (pre-05) is by far the best TPC+ of all TPC -sealed and self-contained.

I'm hating these 3-4 click adjustment that don't do much.

 

[kicknitLivE]

I think Kornflake is right. Your using a damper that is meant to cycle through 130mm of travel, but has been lowered to 90mm. I think you may need the 80mm compression assembly, designed for the jumper.

 

[vitox]

I think Kornflake is right. Your using a damper that is meant to cycle through 130mm of travel, but has been lowered to 90mm. I think you may need the 80mm compression assembly, designed for the jumper.

thats sort of the obvious conclusion


but why?

to the damper its the same thing, the 80mm assy is probably just a shorter rebound rod to set the height correctly.

 

[Kornphlake]

id take a wild guess at a broken shim being the culprit (just a tiny bit of breakage to the one closest to the valve core will do just what you describe)

Is there a seal somewhere that keeps the oil in the stanchion and out of the leg? (maybe whatever seal changed when they went from no-bath to semi-bath) On my fork I could take the compression damper assembly out and compress the fork so that the oil level would rise, then push the damper assembly back into the fork. With the bleed valve completely shut there was obvious resistance, as soon as the top cap was threaded on it was like the oil was going somewhere down inside the leg instead of rising up past the damper. It didn't seem to be a speed or force issue because even without the springs in the fork I could cycle the fork thorugh it's travel by hand with no apparent damping.

 

[kidwoo]

Is there a seal somewhere that keeps the oil in the stanchion and out of the leg? (maybe whatever seal changed when they went from no-bath to semi-bath) On my fork I could take the compression damper assembly out and compress the fork so that the oil level would rise, then push the damper assembly back into the fork. With the bleed valve completely shut there was obvious resistance, as soon as the top cap was threaded on it was like the oil was going somewhere down inside the leg instead of rising up past the damper. It didn't seem to be a speed or force issue because even without the springs in the fork I could cycle the fork thorugh it's travel by hand with no apparent damping.

There's a threaded plastic bottom cap that the damper rod slides though. The damper is a closed system with the rebound and compression stacks just being stuck to opposite ends of the fork.

 

[bomberboy1234]

I have heard putting just normal car transmission fluid can make a fork feel great.