ADVrider

Go Back   ADVrider > Bikes > Trials
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-10-2013, 11:39 PM   #1
Undertheoaks OP
Adventurer
 
Undertheoaks's Avatar
 
Joined: Aug 2007
Location: Bay Area, Ca
Oddometer: 49
Shock re-charging

How often do you replace shock fluid/charge ? Can typical shop do it like a normal dirt bike shock ? Getting ready to do fork and shock and curious to opinions, I have a 05 Gasgas TXT280 PRO.
Undertheoaks is offline   Reply With Quote
Old 08-11-2013, 01:58 AM   #2
Twin-shocker
Beastly Adventurer
 
Joined: Jan 2012
Oddometer: 1,673
If your shock is not sealed and can be rebuilt than changing the oil is no problem. However as you have an 05 bike, unless it has had very little use it would be a good idea to strip and rebuild the shock at the same time. If you have a sealed shock, thats going to mean it will need to be opened up to get at the internals, and parts will be unavailable.

All in all if you want to improve rear suspension, its probably a better idea to spend money on a name brand replacement, rather than messing around with the OE part, which in most cases is likely to be pretty poor quality anyway!
Twin-shocker is offline   Reply With Quote
Old 08-11-2013, 09:10 PM   #3
DerViking
Shred
 
Joined: Mar 2006
Location: Black Bill Park
Oddometer: 309
I ended up with a 2012 GasGas shock when mine lost it's rebound dampening.

A friend of ours tapped a shrader valve into the piggy back, found seals, and was able to rebuild, no problems. I have been trying to bribe him to do mine.

Having just finished putting all new bearings in the dog bones and swingarm, I can highly recommend it as a great way to improve your ride quality. Mine were sloppy....
__________________
ATGATT: When you fall off your motorcycle, you will be wearing what you were when you got on your motorcycle. Dress accordingly.
DerViking is offline   Reply With Quote
Old 08-12-2013, 07:52 AM   #4
Sting32
Trials Evangelist
 
Joined: Oct 2009
Location: Minneapolis, Ks
Oddometer: 1,279
Oaks,

LOTS of trials shocks I believe were non rebuildable (in name only). But I only kind of know my way around what GASGAS produced since 1999. The Sachs shock can be rebuilt, I have had a guy in Wichita, KS that kind of makes them rebuildable (adds a schrader valve as well) with clever knowledge. but if the shop doesn't know how and needs a book to follow they probably wont touch your non rebuildable shock?

Shocks should be ok, as long as they work, when you get better rider you will need to buy new bikes to feel the differences in shocks and everything else, until then? I think it is a wash, but newer shocks and everything do work so different and subtly and in the case of me going from Sachs to the Reiger, you just cannot believe the difference in how they act, but my "novice now going amature" buddy cant really tell you he can feel the difference, until he's gotten used to not only the power difference in my newer bike but every-other nuances...

Ohlins were rebuildable, I know that much, good shock shop, mine in wichita the guy used to be damn good trials rider, so that helps that he knows what he should be tuning for, since I am sure he did his all the time back when...
Sting32 is offline   Reply With Quote
Old 08-12-2013, 01:41 PM   #5
thegraydog
2 wheels X 6 ways
 
thegraydog's Avatar
 
Joined: Aug 2004
Location: the Coconino
Oddometer: 620
This thread is in need of Motobene. I think he said he'd be back in a week or two...

Sting is right about the evolution of suspension. I'll go for the best when I can...
thegraydog is offline   Reply With Quote
Old 08-13-2013, 02:00 PM   #6
StuInFH
Gnarly Adventurer
 
Joined: May 2012
Location: Central CA
Oddometer: 400
Quote:
Originally Posted by Twin-shocker View Post
If your shock is not sealed and can be rebuilt than changing the oil is no problem. However as you have an 05 bike, unless it has had very little use it would be a good idea to strip and rebuild the shock at the same time. If you have a sealed shock, thats going to mean it will need to be opened up to get at the internals, and parts will be unavailable.

All in all if you want to improve rear suspension, its probably a better idea to spend money on a name brand replacement, rather than messing around with the OE part, which in most cases is likely to be pretty poor quality anyway!
A club member rebuilt his and he can tell you the +/-s, PM me and I will share his ID. Motion Pro provided him with seals/bushing based on size and configuration, not the brand. Then he installed the snowmobile type valve (cuz not enough room for standard Schrader) that a local suspension shop was able to use to pressurize it (using tool for Ohlins).

But I agree with TS' comments, after looking into making my non-rebuildable OEM Olle into a rebuildable one, It seemed wiser to opt for a custom unit from WorksPerformance, down in Canoga Park. More adjustability and easy parts/service from then on.

StuInFH screwed with this post 08-13-2013 at 02:10 PM
StuInFH is offline   Reply With Quote
Old 08-18-2013, 06:45 PM   #7
garrett
Gnarly Adventurer
 
garrett's Avatar
 
Joined: Oct 2006
Location: Calgary
Oddometer: 438
I have an '05 Beta Rev3 with a Paioli rear. My local suspension guru rebuilt it and told me the there are a LOT of funky internal valves but he had no problem. The shock was much better after the service.

Garrett
__________________
I like bikes...
garrett is offline   Reply With Quote
Old 08-26-2013, 10:04 AM   #8
motobene
Motoing for 43 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,019
Quote:
Originally Posted by thegraydog View Post
This thread is in need of Motobene. I think he said he'd be back in a week or two...

Sting is right about the evolution of suspension. I'll go for the best when I can...
Back from Switz!

Nice to be needed!

The need to rebuild a shock depends. If it's working well and you see no oil weeping at the shaft seal, it's hard to justify breaking into the shock unless you have lots of experience or know someone who does. If it's working fine don't mess with it unless you want to re valve the shock to speed it up (more on that below).

I'd not be getting into a shock for prophylactic maintenance on any bike that doesn't have significant time at high forces (higher level riding or abusive trail riding). If you see a weeping shaft seal, that's a good time. By weeping I mean it will be more than a moistness. It will leave rings of oil on the shaft as you stroke the shock and you'll see significant dust accumulation below the shaft. In that case it's just a matter of time before internal pressure drops near zero and the shock suddenly 'blows', which is major oil loss and/or severe damping loss. Then you'll be replacing the shaft seal or seal head, and hopefully your shock shaft will not be scored or the chrome flaked. If the shaft is damaged, a rebuild will be vain if you don't replace it.

I bought my Econo a while back and bought also an older gold-anodized Ohlins GG45. Unfortunately it was one with problems. Correspondence with Ohlins had them telling me BS about the shock not being re buildable... that it could be rebuilt only with some special machine in Sweden. That was not something I wanted to hear.

Some further discussion with an Ohlins engineer turned up a weakness in the design: bare minimum internal volume, and he arranged to sell me parts and give me specs. I bought a new seal head and their recommended oil. I decided the internal piston for the gas reservoir was displacing too much volume. I have made trials shocks without a piston for the gas reservoir, a so called 'gas-emulsion' format where the nitrogen bubble simply sits in the top of the shock. Gas emulsion is a bit of a misnomer because you don't really get gas passing through the valve stack and a loss of damping. I dare say this Ohlins as configured would work near as well as the Reiger on my Raga if put on the Raga, which has the newer linkage with a lower rising rate (thus less abrupt feeling).

With no piston in the top of the shock, I guessed on the oil level, tossed their gas filler for a stubby Schrader (machining required), and charged to about 80 psi nitrogen with a simple Schrader air valve and dead reconing. It's worked fabulously. So much for dire warnings and 'un re buildable.'

My latest bike, an `11 Raga 300, has the very small body, high quality (and expensive) Dutch-made Reiger. Mine has the puffed-out top/reservoir with the added compression damping adjuster. Aside from fiddling with the adjustments, I'll not be touching this shock unless it has some problem, and I doubt it will for a long time.

Shocks are closed systems. When working normally, the only interaction with the outside is from forces placed on the shock in compression and the spring forcing the extension (rebound). Internal gas pressure translates through the oil to have the shaft seal put a high pressure death grip on the shaft. Unless you really abuse the shaft and seal with abrasive slime, nothing is going to get in there from the outside. That leaves oil shear and internal pollutants to degrade the shock.

Oil shear is simply fatigue of the oil molecules by being squeezed through the valve stack a gazillion times. Heat isn't much of a factor with trials shocks. Even though their bodies are really small, we tend to do intense things for only short bursts and the shocks get only a little warm. If you race around a really wooped-out loop non stop, the shock get really hot. But how often do we do that?

Modern shocks typically use high quality oils. I don't know if the factories use the ester-based synthetics, but even if they don't the oil is pretty good and it will take a ton of abuse to shear-fatigue the oil.

The primary reason for rebuilding a shock for maintenance reasons is the buildup of suspended internal pollutants. These are particles that get sloughed off into the oil from parts moving over each other. The better the shock design and materials, the less fast it will slough off particles. Most modern shocks tend to not have bare aluminum bores sloughing off aluminum oxide particles, which are highly abrasive and can lead to more particles being sloughed off. Some non-cartridge fork legs and cartridge bodies are bare aluminum, and you've seen the resultant grey oils when you change them. Get a lot of particles in oil and wear accelerates.

A minority of shock oils have lubricating particles in a colloidal suspension, like molybdenum disulfide. Moly oils will start out as a grey/black fluid. I used to build gas-emulsion trials shocks based on Works Performance shock parts. They recommended a moly oil, perhaps because their shock bodies were bare aluminum.

The typical higher-end shock body these days is anodized aluminum or in some cases, steel. Anodizing forces the surface to convert to aluminum oxide, which is a wear resistant transparent coating. It's only a few ten thousandths of an inch thick, and pigments are often added for looks. Steel bodies tend to wear pretty well, as in little, coated or uncoated.

What does it take to rebuild a shock? First is experience! It can be very frustrating if you don't have it. There are certain tricks that are hard to describe on a forum. If you lack the confidence, and you are going to do it, have someone experienced do it.

I've done many shock rebuilds with simple tools. If the seal isn't leaking, I don't replace it. Seals will last a long time if the oil is clean and the shock shaft and seal have not had to run in gritty slime. If a shock body lacks a simple Schrader connection for gassing up the shock, I'll machine for 1/8 NPT and fit a stubby version. Take care that you have room for even a stubby Schrader at the upper eye area, one direction or the other! I use the best quality and thinnest ester-synthetic shock fluid (not fork oil) I can find. Shock fluid is very low viscosity, which helps keep the shock moving modern-fast.

If you are rebuilding an older shock, as in early 2000s and later, keep in mind the evolution in damping specs, which has been from glue slow to very fast, particularly in rebound speed. It used to be that the minimum rebound setting was still too slow for modern trials. The Raga I just bought I found to be right, as in too fast at minimum settings, so I actually have some adjustment!

Take extra care to chose the thinnest oil you can find when rebuilding older shocks, as in the lowest SSU numbers or the vague "very light" or SAE 2-1/2 shock fluid. Over damping is like living on a planet with more gravity, and the further back you go in model years, the slower damping tends to be from the factory. I just rode a Kawasaki KLE500 in Switzerland. It's a 2000s model but an `80s design with glue-slow suspension. The shock was so over damped it would pack down in corners, causing gross under steer when doing Switzerland's twisty mountain pass roads. And no adjustment so no minimum setting to make things LESS wrong

You may also benefit from some re valving, like removing the shims from the compression and rebound valve stacks, or shuffling one of the smaller diameter shims to lower in the stack between the larger diameter shims so they will flex up off the piston easier. This may require multiple tries, but don't be so bashful on the `90s and older bikes. Don't forget to speed the forks up to maintain balance between front and rear, and often you can do that with the thin fork oils.

A quick test of suspension balance is to put both hands in front of the 'seat' area and push down fast and let the bike come back up to you. Watch for how fast the front and back ends come back up to you. One should not lag the other by much.

Hope this helps....

motobene screwed with this post 08-26-2013 at 04:40 PM
motobene is offline   Reply With Quote
Old 08-27-2013, 01:51 PM   #9
Jonny042
Adventurer
 
Joined: Mar 2012
Oddometer: 71
Shock Heat

Motobene, thanks for the very educational post!

I have a '12 "race" with the single adjustable reiger, which lost its charge and damping after a few months of use.

I sent it back to reiger over the winter and they rebuilt it, and they claimed the oil looked very dirty and "used".

I am now uneasy with this shock - the bike seems to be under-damped, even with the damping adjuster at 3 clicks from maximum, it seems a little "fast", especially in creek type sections. I am wondering if it is on it's way out again, but it does seem to have it's charge still (extends itself on it's own at least).

For the 2013 "not-raga" and the 2014 race, the reiger shock has been flipped right side up to keep the oil from the heat of the exhaust, and I can't help but wonder if that is an admission that the "upside down" mounting is the wrong way to go. Any thoughts on that, or on my shock dilemna?
Jonny042 is offline   Reply With Quote
Old 08-27-2013, 05:52 PM   #10
laser17
Studly Adventurer
 
Joined: Mar 2008
Location: Boston,Massachusetts
Oddometer: 703
Does your damping change as the shock/exhaust heat up? If so, you can try some reflective tape to reduce the heat absorption into the reservoir. If not and its supper fast - seems its shot. All the guys riding reigers I know end up speeding the stock settings up as the middle setup is fairly slow. I know two clicks on my shock (Raga model) is noticeable and 5 clicks is a huge change. Gets REALLY slow even with my HD spring on it.

I would ask Reiger to make it right - they seem to be fairly good in the customer service arena. If you have a 2nd problem on the same shock, I would seem to think they may take a better look. Ask them about the heat and why they changed. If its a design issue, I would think they may help out with an upgrade or suggestions. Talk to Stu - he knows the main guy over there who sets up Ragas bikes. Stu may even set you up with a full adj loaner while you wait if he hasn't already loaned it out.
laser17 is offline   Reply With Quote
Old 08-27-2013, 06:32 PM   #11
Jonny042
Adventurer
 
Joined: Mar 2012
Oddometer: 71
Hi Laser, Stu got me in touch with the guy at reiger and I dealt directly with him - I had previously sourced stiffer springs via Stu, so asked his advice and he was nice enough to share his contact info.

I played with the damping (cold) out in the yard today, and compared it to the ohlins - the ohlins has a much wider range of adjustment, but it is possible to set it too slow. The Reiger seems to have less adjustment but down to 1 click from full feels overdamped, but only just barely. I am going to play a bit more next time I go riding (and get the shock good and hot).

When you say 2 clicks/5 clicks, do you mean 2 clicks out from full? 2 clicks out from full feels about right to me, 5 clicks from full seems too fast. 15 clicks from full and there may as well not be a shock at all.

For what it's worth, and for curiousity sake, I played a bit with compression and rebound damping on the front and found the range of adjustment is similarly small, as in, the difference between max damping and min damping is not really very large - this made me feel better about the amount of damping I am getting from the shock (as in, they seem well matched). Either that or my forks arent dampening well, either.

All this lack of damping means the bike is awesome for "trick" riding, hopping, zaps (lots of rear wheel lift), etc. but also seems like it gets thrown off line in rough stuff like rocky creek beds. So in other words good for goofing around but I am sure I would take fewer points if I could slow it down a bit more, like the 2011.

Thanks and all the best, Jon

Quote:
Originally Posted by laser17 View Post
Does your damping change as the shock/exhaust heat up? If so, you can try some reflective tape to reduce the heat absorption into the reservoir. If not and its supper fast - seems its shot. All the guys riding reigers I know end up speeding the stock settings up as the middle setup is fairly slow. I know two clicks on my shock (Raga model) is noticeable and 5 clicks is a huge change. Gets REALLY slow even with my HD spring on it.

I would ask Reiger to make it right - they seem to be fairly good in the customer service arena. If you have a 2nd problem on the same shock, I would seem to think they may take a better look. Ask them about the heat and why they changed. If its a design issue, I would think they may help out with an upgrade or suggestions. Talk to Stu - he knows the main guy over there who sets up Ragas bikes. Stu may even set you up with a full adj loaner while you wait if he hasn't already loaned it out.
Jonny042 is offline   Reply With Quote
Old 08-28-2013, 06:41 AM   #12
motobene
Motoing for 43 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,019
The Reiger does have a very small diameter body, so pressure will be high and hard on the oil.

The Reiger I have came to me well certainly 'broken in' under the hammering feet of an Expert rider. That rider's preferences were for very fast suspension response. Too fast in my opinion. The forks topped out and the rear responded so fast it'd bounce back fast when slamming into a rock face. I kept adding clicks until I struck a balance between quick and calm, which as I said earlier was right in line with what a Reiger video said was their recommended starting settings, roughly in the mid range.

Sounds like your shock isn't quite right because you're having to max out your settings. Perhaps something is going on in there that will trash the oil faster?

I noticed my Reiger has a wrought aluminum, thread-in body that is hard coated (hard coating imparts a transparent greyish or greenish or greenish-yellow cast to aluminum, depending on the alloy). Hard coating is aluminum oxide like anodizing, but it is 10X thicker than anodizing. It's about the best wear surface you can have in a shock body, and the base aluminum is great for thermal transmittance. Hard coat almost eliminates entirely the slough-off of particles from the piston-body interface.

As for that second adjuster, I don't think that's so important. I was surprised Reiger's compression adjustment actually did something, because the typical compression adjustment is only meters slightly the tiny volume of oil being displaced by the stroking of the rod, which on the Reiger is very small in diameter. Contrast this with the typical rebound adjuster which is an adjustable bypass of the rebound valve stack and thus much higher in volume of oil displaced.

Another way to think about adjustments is that if the shock is valved right enough you don't need adjustments. They are quite nice to have when things aren't right of course. And if you are to have only one adjuster rebound is definitely the one to have.

The compression-adjustable Reiger is an oddity, because it appears to increase reservoir size. Higher oil volume, greater thermal mass and heat shedding potential (more surface area) from the bulged reservoir area is a good thing. This may make the 2-adjuster version a bit more robust.

As for right side up or upside down, when you have a DeCarbon-type piston or bladder reservoir shock like the Ohlins and Reiger, it doesn't really matter which way they are assembled. The stroking mass is about the same either way. Rod-up can be a little harder on the rod and seal and shaft because crap can more easily collect around the seal area. But trials bike shocks are fairly well protected, and rod-up puts the shaft farther away from the ground, as well as the body farther away from the muffler side.

The body-up heat issue makes sense because the body and muffler are right next to each other. I'll check out flipping mine over. A quick, rough measurement of the eyes at either end may not be the same width. Another option is to leave the shock body-up as on most bikes, and simply shield the body from the infra-red heat radiating from the side of the muffler. Ceramic cloth bonded onto the muffler with silicone 1, or a hanging thin aluminum sheet between muffler and body would help.

It can get really hot in the upper shock cavity area. Hot weather plus little wind plus aggressive loop trails, and extremes like catching the oil on fire in the muffler. You build up oily carbon on the header pipe and oil load the muffler packing. Then you do something like blast down trails sustained or go up mountains sustained. The header catches fire, then the fire works in a wave back into the muffler. When this is happening the bike will blubber like fouling the plug and a ton of smoke will come out. It's good for the bike to burn the crap out, but you'll want to do this in 2 or 3 stages, not all at once. I once melted a brake line on a Fantic being very aggressive at burning out a pipe!

motobene screwed with this post 08-28-2013 at 07:13 AM
motobene is offline   Reply With Quote
Old 08-28-2013, 09:11 AM   #13
laser17
Studly Adventurer
 
Joined: Mar 2008
Location: Boston,Massachusetts
Oddometer: 703
Hi Jon - I was referring to clicker changes relative to the current settings that are fairly close to the stock factory setup. Compression is probably 2-3 clicks faster and rebound is 2-3 slower (I use a HD spring). I played around a fair bit with this and it was the 1st shock where I could really feel small changes. Sorry - I never tested the near the max/min limits on the reiger.

I would still send it back through Stu. Reiger is more likely to try and make him happy than you and fix it for free even if it looks used- he's sold several high end shocks for them. (This is an assumption on my part) Cant hurt and Im sure Stu will back you up and hook you up with a loaner in the meantime. (my guess is that You'll probably still be on the hook for shipping though)

Trebor

Forgot to mention - the front fork adjustments (zokes) dont do a whole lot. Ive always made adjustments to them via oil and spring changes. My current bike (stu's 11 raga) came with custom re valving and oil for us gravity challenged. SOOooo much better than my 09 with just HD springs. Doesnt deflect as much - yet will soak up the big hits w/o a harsh bottom out. It may not be perfect for a jumbly stream bed though. Balances well with the rear too. I have no experience with the Tech forks - but hear they offer better adjust-ability via top of fork dials - but cant find HD spring for them so far.

laser17 screwed with this post 08-28-2013 at 09:53 AM
laser17 is offline   Reply With Quote
Old 09-07-2013, 07:35 AM   #14
motobene
Motoing for 43 years
 
Joined: Mar 2013
Location: Wichita Mountains SW Oklahoma
Oddometer: 1,019
If you get here, search also for my two threads, Inside the Ohlins GG45 Shock, and Inside the Reiger Shock. They will cover more of what's inside the shocks, and oil and recharging.

motobene screwed with this post 09-07-2013 at 07:51 AM
motobene is offline   Reply With Quote
Old 09-08-2013, 11:20 AM   #15
Undertheoaks OP
Adventurer
 
Undertheoaks's Avatar
 
Joined: Aug 2007
Location: Bay Area, Ca
Oddometer: 49
Thanks for all of the info, great stuff and knowledge well taken into the memory banks.
Undertheoaks is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 09:01 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014