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Lowering fork internal

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I've got some friend here doing Ice racing, usually they drop their suspension.

 

I know racetech do some spacer for the rear, but for the fork, how I can do it securely and reversable ?

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If it's an open bath fork then you generally have to make new springs and shim the damper rod the same amount.  For a cartridge fork you generally have to cut a new circlip for the spring seat and shim the damper rod.  Both are reversible but one just costs a lot more.

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In the threads I've read about lowering suspension, the "cutting a new circlip for the spring seat" is never really covered in any detail (that I've seen).

 

I see mine, I want to move it, but have no idea how.  Would a "regular" machine shop have what I need to remove that one, and press on a new one; or do I need to special order parts for this?

 

see attached

 

2009_yz250f_forks.jpg

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If you move that part down towards the bottom you will expose the clip

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The clip on the KYB forks you have in front of you is hidden by the ring as mog said.

Unfortunately, you cant just move it down, you have to cut it off.

 

The new groove has to be lathed into the cartridge by a trained technician.

Alternativ:
Use a ID28 alloy tube to hold the spring seats where you want them. The tube sits against the lock not on the cartridge.

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Would a "regular" machine shop have what I need to remove that one, and press on a new one; or do I need to special order parts for this?

I had my local machine shop cut a new groove on mine. Definitely not something you can do at home.

I bought replacement spring perch stops and circlips from Suspension Direct. Takes a minute to install those.

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thanks very much, you guys rock!!!!!!!

just knowing that I need to cut that (how do you dremel it without hurting the tube?), and knowing I need to order "spring perch stops and circlips" is golden.

thanks guys!

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(how do you dremel it without hurting the tube?)

 

Just take your time.  You don't have to cut all the way through it (as can be seen on the right hand side of the stop.  I cut through most of it and then put a flat head screwdriver in the slot and twisted.  Broke the remaining part of the stop.

 

2-9-12-1.jpg

Edited by H-B-R

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Once more, a thousand thanks!  I dremel'ed it until it was almost cut through; then took a big flathead, twisted, and I could see the ring underneath.

 

All that fuss for that skinny little ring.

 

Now I just need to order my new "spring perch stops and circlips", get new grooves cut by a professional, and I'm golden!

 

thanks so much

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hey as a side question; you can determine how much you want to lower your forks; and you get to decide how much to preload the springs.  If you didn't move the spring seat perch stop, the spring would be preloaded by the amount you're lowering, correct?  So how much you move it determines the amount of preload you're putting on your forks.

 

Is there any advantage to preloading them just a little?  You've removed travel, don't you want your springs to be maybe a little bit in the stroke?

 

Like if you lowered your bike 20mm, like maybe you only move the seat perch 15mm?

 

...or does this take away the "initial plushness" factor?

 

(I suppose you could cut the new groove the whole 20mm away; then shim for preload if desired.  The question still stands; to preload, or not to preload, after lowering?)

 

thanks again

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I think you also need to make a travel limiting spacer.

Yes you can change spring preload when recutting the groove. Or have the machinist cut multiple grooves, for different preload positions.

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I bought two travel-limiting spacers from race tech.  They are tapered to match the KYB forks where they go.  I have cut them, but haven't "prettied them up" yet.  I just didn't know about the spring seat thing.

 

thanks for the idea about the multiple grooves!

 

 

has anyone else who's done this think that some extra preload was good, or is the preload you were happy with "unlowered" considered good?

 

I'm probably overthinking this...

 

2009_yz250f_forks_and_spacers.jpg

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What material are the RT spacers made from? I'm in the middle of making some for my fork lowering project. How tight a fit are they on the damper rods? I'm worried that too loose a fit would let them slide around on the rod, scratching the anodized surface.

I think spring preload is a tuning variable that mostly influences the first few inches of travel. I would think less for trails, more for MX.

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The race tech spacers appear to be made out of plastic...?  I can't really tell.

 

One of the attached pics still has the dust on it from cutting it... gave it some depth.

 

I put it over the rod to "try it on for size", and when it slid down to the damper assembly at the end, it kinda stuck there.  I had to pull it off.  It wasn't locked in like glue, but once it was pushed on there, it didn't seem like it wanted to just fly off willy-nilly.  It appeared to fit nicely.

 

I wanted to lower my forks about 20mm (an inch is about 25mm).  They sell spacers that are two inches.  Why would I buy two, I wondered, when I could just cut one in half?

 

Answer:  because they come with taper that matches the internals of the forks.

 

So that meant with shipping, $52.44.

 

Kinda yowch, but with the cartridge spring perch clip and holder (which I ordered three of just in case) costing $33.26 with shipping... that means I'm still under a hundred bucks ($85.70).  Need to pay a machinist friend to cut groove(s), and then fork oil will be in there too, so call it somewhere over a hundred bucks to lower my forks.  I can live with that.

 

 

 

 

race_tech_fork_lowering_spacer.jpg

race_tech_fork_lowering_spacer2.jpg

race_tech_fork_lowering_spacer3.jpg

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