All 2st DIY shock service?

[budpat105]

Been thinking about doing my own rear shock lowering. Looked at service and looks to be an do able task. Sometimes looks can fool you. What do you say? Thanks

 

[Kyle Tarry]

Are you going to put the lowering spacer between the seal head and the top-out spring, or between the seal head and the circlip?

 

[juicypips]

dont you have to re pressurise the shock with nitrogen?
that would be the only thing i would be concerned with.

 

[Motosportz]

dont you have to re pressurise the shock with nitrogen?
that would be the only thing i would be concerned with.

You can use air in a pinch and most shops will pressurize it for a small fee.

 

[budpat105]

lowering spacer going between top out spring and seal head, have a small local shop that will do nitrogen, but the actual disassemble of shock looks like it's not real hard.Just didn't know if I was overlooking something.

 

[Motosportz]

lowering spacer going between top out spring and seal head, have a small local shop that will do nitrogen, but the actual disassemble of shock looks like it's not real hard.Just didn't know if I was overlooking something.

it is not hard, a few tricks to learn but not a big deal. Getting the piston or blatter in right and the oil air free is always the fun part to me.

 

[Kyle Tarry]

I think that some of the Sachs shocks require that you remove the entire clevis assembly to get the top out spring off... Pretty sure that mine has a circlip like the midvalve bottoming cone.

 

[Arctra]

Been thinking about doing my own rear shock lowering. Looked at service and looks to be an do able task. Sometimes looks can fool you. What do you say? Thanks

Do it mate... it's not that difficult. See my DIY post here: http://www.cafehusky.com/threads/diy-sachs-shock-service.36344/

 

[budpat105]

just saw on race tech web page that their lowering spacers are not recommended for shocks with top out springs. Time for more research.

 

[Picklito]

It's just because the typical spacer is soft plastic like nylon, and the spring can chew it up. The dual Ohlins on my older husky's used an aluminum spacer and I wouldn't hesitate to make one and run that between the top-out spring and the seal head. Yes, aluminum is soft, too, and over a LONG TIME could wear a bit as well, but should not a an issue in a normal shock oil change interval. Plus... you'll be able to do it yourself!

 

[Kyle Tarry]

Does anyone know why they put the spacer between the top-out spring and the seal head, instead of between the seal head and the snap ring?

 

[uranys]

It seems like that would work too. I think an adjustable clevis would be the best solution.

 

[MotoMarc36]

Does anyone know why they put the spacer between the top-out spring and the seal head, instead of between the seal head and the snap ring?

In this manner you are limiting the oil capacity which is never desireable. Sure the spacer displaces some oil but not as much as moving the whole sealhead upwards. But in thinking about it, that is perhaps splitting hairs and not much of a factor to consider.

A very real disadvantage to putting the spacer between the sealhead and snapring, is moving the guide bearing in the sealhead closer to the the other bearing, the piston ring. This can have all kinds of real-world negative effects like increased sideloading and stiction, accelerated wear on bearings, oil, and shockbody surfaces, etc.

I would think some carefull chamfering of the topout spring should minimize any issues. I've had decent results with "schedule 80" PVC spacers in forks, don't see why it wouldn't work in a shock.

 

[Kyle Tarry]

Interesting points Marc.

I'd argue that, while you're sort of correct on the bushing-piston distance, you could also argue that it hasn't changed at all. At full top out, the distance will be the same as it always was; at rider sag, the distance will be the same as it was without the spacer, and at, say, 10 inches of wheel compression, the distance will be the same. The only thing that is different is that both the piston and the seal head are deeper inside the shock body for any given wheel position, which I don't think is especially bad, but I could be missing something.

The problem with the topout spring in a shock (compared to fork spacers) is that fork springs are always preloaded, so there isn't any impact or much relative motion between the spring and the spacer. In the shock, the topout spring moves with the piston (I think? Am I remembering that right?), so every time you top out it smashes into the spacer. Lots of shocks don't have topout springs, so in those it probably doesn't matter.

I've though about lowering my WR a bit, and if I did I think I would put the spacer behind the seal head... Have to think about it more though...

 

[Picklito]

Good stuff man! Some shocks have the top out spring built into the seal head (some years KTM PDS) and some have it 'moving' with the piston. I don't think it matters. The 'mashing into the spacer' thing would be essentially the same either way. But, if we think it through, the original metal disc that acts as the extension stop (sometimes called rebound disc) also mashes into the spring every time the shock tops out.

 

[budpat105]

I agree good stuff!! I think I can dig up a piece of aluminum and cut one out with a hole saw. I called race tech and they said I could remove the top out spring if there was a rubber bumper inside. Think I will leave spring and use the aluminum spacer.