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SE/SP Rear shock rebuild


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kiwisteve74

 
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SE/SP Rear shock rebuild

Sun Sep 18, 2011 10:56 am » Post: #1 » Download Post

Hi guys, there are lots of references made in various posts about rebuilding or re-gassing the SE/SP shock. I have done quit a few rgv250 shocks in the past and they are easy enough to do, however looking at the NSR shock i will have to weld a schrader valve to the back cap of the reservoir cylinder? Also i cant see how it works? the rgv showa shock has a bladder which is pushed into the reservoir and once locked in place is filled with nitrogen to displace the oil. The NSR one seems to be the reverse with the bladder in backwards placed under pressure by the nitrogen surrounding it? is this how it works? i have replaced the oil and removed the air but is the bladder normally full of nitrogen or oil? I cant see how it would work???

I wonder if someone has had it apart and assembled it incorrectly?

anyone done this?
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nxrsr20

 
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Sun Sep 18, 2011 7:49 pm » Post: #2 » Download Post

This is all vague as hell, but I had a shock recently rebuilt and all they did was put a schraeder valve on the reservoir. I don't know what they did because it was done by a so called "guru".
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kiwisteve74

 
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Mon Sep 19, 2011 4:34 am » Post: #3 » Download Post

yeah, i know i have to add a schrader valve but this will put pressure in behind the bladder and not in it, i guess the bladder is filled with shock oil instead of nitrogen and the nitrogen surrounds the bladder?
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Matt@TYGA
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Mon Sep 19, 2011 4:53 am » Post: #4 » Download Post

If you can fit the valve then it's straight forward. I've done many.

The bladder has the oil. You gas up the reservoir on the outside of the bladder. It's no different really to gassing up the bladder.
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kiwisteve74

 
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Mon Sep 19, 2011 8:09 am » Post: #5 » Download Post

thanks matt, just making sure im doing the right thing. how the hell do you get the oil in the bladder and bleed the air out those two little holes? I will give it a crack later on.
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Matt@TYGA
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Mon Sep 19, 2011 8:25 am » Post: #6 » Download Post

kiwisteve74 wrote:how the hell do you get the oil in the bladder and bleed the air out those two little holes?


And that's why people who rebuild suspension can ask you for a fortune and then ask you to leave the workshop Wink
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kiwisteve74

 
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Mon Sep 19, 2011 8:42 am » Post: #7 » Download Post

fair call Matt, I do all the work on my bikes myself as i like to understand how things work. I got sick of taking things to bike shops and have them coming back with vice marks and hammer hits all over them. Im a bit of a perfectionist when it comes to things mechanical. The more i try the more i learn, the more i learn the more i understand.

I got a few ideas how to get the air out of the bladder, i will grab some nitrogen out my work van and we should be good!
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Matt@TYGA
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Mon Sep 19, 2011 9:10 am » Post: #8 » Download Post

I understand your predicament with shops.

One trick is to use the bladder as a sort of squeezy.........put oil in the shock body, give the bladder a squeeze and let it suck the oil in. After that, careful positioning of high points and you can bleed all the air out with a bit of a squeeze and suck here.....and a tap with a mallet there.

One thing that may cause some shock builders an issue is that air can sometimes lurk in the valve under the shim stack. Just pushing the valve through the oil slowly doesn't release it as the shims never open and the oil goes through the bypass or low speed orifice. A strategically aimed sharp crack or two with a mallet opens the shims enough to release the air.
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kiwisteve74

 
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Mon Sep 19, 2011 10:46 am » Post: #9 » Download Post

All done, didn't take too long, the only problem i struck is that i didn't notice the split ring that enables the two bottom plates to separate for spring removal and i ended up taking the lower eye/adjuster off to remove the spring. when i screwed it back on i messed up the adjustment screw so it didn't work. i had to remove it and re-bleed. I noticed the split ring when i went to refit it. there is no air in it now and i filled it with 150psi of nitrogen. it seems real soft but i need to wind the preload back into it as i backed the rings right off. will try that tomorrow night.

thanks again for the help Matt.
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Matt@TYGA
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Mon Sep 19, 2011 11:01 am » Post: #10 » Download Post

With it full if gas, fully compress it and allow it to extend. You can fiddle with the rebound adjuster at this point to check that it's functioning properly.

Also, if it doesn't fully extend then there's air in there. Or if when you fully compress it it quickly moves a couple of mm before the rebound damper takes effect, same problem.

Anyway, good on ya for doing it.

FYI, the shimming on the stock shock and the F3 shimming are very different. Early F3 shocks also have a very different valve. Later F3 shocks use the same valve as an NSR, which is same as CBR250RR, VFR400, RVF400 and plenty more I'm sure. In fact, they all mostly use bits from the same parts bins.

I've not tried a double shim stack on the rear, but it works on the forks. Gives a real plush ride around the town when you're cruising, but then stiffens up at full tilt.
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2T Institute
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Sun Sep 25, 2011 1:47 pm » Post: #11 » Download Post

kiwisteve74 wrote: The more i try the more i learn, the more i learn the more i understand.


Then there is realisation. That you can go to work and earn more than it costs in the same amount of time it took you to do the job Very Happy Very Happy Very Happy . I'm surprised nobody uses thes shocks which are bloody good and extremely well priced. I get them from the UK and for much cheaper than any local suspension places for the same features.

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Matt@TYGA
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Sun Sep 25, 2011 2:12 pm » Post: #12 » Download Post

Once you know the insides of a shock it's pretty easy to then be able to shim and damp it to compete with most aftermarket stuff. Ok so a steel body's not as trick as aluminium but it's always good to be able to do it yourself. And in my book the knowledge gained by hands on experience is worth it
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anonymous.shyster
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Sun Sep 25, 2011 8:01 pm » Post: #13 » Download Post

2T Institute

Care to give us more info on the shock in the teaser pic?
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shmokica

 
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Mon Sep 26, 2011 12:53 am » Post: #14 » Download Post

Took a guess. Google Nitron. Smile
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2T Institute
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Tue Sep 27, 2011 10:18 am » Post: #15 » Download Post

Matt@TYGA wrote:Once you know the insides of a shock it's pretty easy to then be able to shim and damp it to compete with most aftermarket stuff. Ok so a steel body's not as trick as aluminium but it's always good to be able to do it yourself. And in my book the knowledge gained by hands on experience is worth it

Sometimes it is, sometimes it isn't.I spent lots of time and lots of $$ getting a 'cheap' set of Swedish $hitter Shocks to work on my vmx bike. Bit the bullet and bought a set of YSS shocks have not touched them since I bolted them on(except for setting the rebound) I reckon I spent less on buying the YSS than I did, shims, seal heads springs etc etc. Not to say that the knowledge isn't worthwhile I just don't have the time to play with suspension gizzards. Very Happy

Yes it's a High/low speed comp Nitron <$900 AUD landed, colour grows on you especialy after you go for a ride.
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