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revalving showa bv piston assembly on a showa TAC fork while in the clamps?

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Curious if anyone has pulled the 47mm showa bv piston assembly on a showa Twin chamber spring fork out and revalved it

while in the clamp? I want to change up the BV stack but don't want to pull the whole fork/ cartridge assembly apart. I've never done it this way... so curious if it's doable? Wondering about bleeding the cartridge too as I usually do it when the fork is apart. 

 

Let me know if you've done this and if it's OK to do?.... txs,

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The for is off a 2005 CRF250R... it's not a TAC air fork...

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Yes most people add 5cc of oil when doing so

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edit : deleted my post

 

To OP, give it a try and tell us how it went.

Edited by mlatour

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I've done it on my bike. as moggy said, if you add some oil, you'll probably be okay. the cartridge rod did fully extend the next time I did seals on the bike. not what I would do for someone/customer, but it worked on my personal bike. now, I've acquired a 2002 cr250. I will probably be doing that procedure a few times when i'll fine tune the woods setup for me. that's until I score some air forx for it. lol

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It can be done but why unless you only pulling the base it's going to take longer and your guessing the cart is bleed correct

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Just pulling the base vale assembly... just did a revalve on the fork and want it to have a softer feel on the small bumps... I'm going to lighten up those bleed valve shims a lot since I've had that affect small bump compliance in the past. And I'm going to lighten up (smaller cross over... pull a few LS comp shims) the compression stack.

 

Again, looking for that small bump compliance. This is an off road setup I'm after.

 

I will tell you all this...I went pretty darn soft on the shock valving and it worked much better then I thought it would!  I actually pushed up and down on the shock while on the bike before riding it and thought "I think I'm toooo soft here".. Nope, bike tracked so much better and put more power to the ground as the rear wheel was able to stay in contact with the ground on the small chop. It was a big delta. I put a bleed shim one shim down from the face shim and two shims from that is a cross over. I didn't expect  to get this feeling I mentioned out of it. Now it could use a little more compliance on small stuff and a little more bottoming resistance (could add a few hs shims.. pull one or two LS from the shock). But it's super ride able as is. Just trying to get to the most ideal setup. I think I can nail it now. 

 

The forks were better but need to be softer for those smaller off road bumps... 43Kg springs, 1.4 ICS spring... so we'll see what the changes will do. 

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Not familair enough with Showa TAC forks but if bleeding the cartridge is similar say to purging KYB / SSS fork cartridges

I just can't imagine purging out the extra air/oil properly with them installed. Post a video I'm curious to see how it's done.

Edited by mlatour

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You rely on the bottoming of the fork on the next hard landing to purge them

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You rely on the bottoming of the fork on the next hard landing to purge them

 

So let's say I did a bad job with bleeding the air from my cartridge, If I go riding and have a few heavy landings, is it safe to assume my cartridge is now air free? I haven't ever heard of this before... Thanks

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Again if the cartridge assy is similar to a KYB / SSS.

If following a hard landing the rod is fully stroked that it bleeds / purge the inner cartridge,

that would mean any excess air/oil would be sent into the outer chamber ?

 

Does the outer chamber of the damping side fork of the TAC system contain oil?

If it does, the purged cartridge would alter the oil volume.

 

I have to look up how a TAC functions...

Unfortunately videos on YouTube mostly focus on the air side for detailed explanations, not the oil side.

Edited by mlatour

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Yes when you bleed them,you can't do more than bottom the rods ? Most tc forks cycle oil from the inner chamber to outer chamber ,so to a degree that should self prime

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It worked fine... on my 2nd revalve attempt of the BV. Still having a hard time getting that small bump compliance. RaceTech spring calculator states I should be running a ~ .41KG spring. I have a .43KG spring in it. The stock X springs are .42 and the R's are .45. 

 

I keep lighting the valving/ bleed and am not getting the softness initially I desire. I'm thinking I should try the softer springs though. hmm... Anybody got a set of .41KG showa TC springs around? 

 

PT

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.41 spring... .43 spring....

 

Hold on, what type of fork are you talking about here,

the title of the thread says 'Showa TAC fork'

 

doesn't TAC refer to a 'triple air chamber' design meaning there are no mechanical springs but rather air.

Edited by mlatour

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Look the second post down... not a TAC fork. It's a 47 Showa spring fork from a 2005 CRF250R

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