Ohlins Twin Shock Expectations

[1982 XC 430]

Hello, on my 82 250 XC I have a 99 KTM Front Fork setup. The Ohlin Shocks were gone threw, and by that I mean that a Local Shock rebuilder and I took them apart and reasembled them useing new Seals and Oil. He has his own busness doing modern single shocks and had never done a twin shock before. I was helping by holding the drawing and keeping track of the parts. We spent quite a wile making sure they were full of Oil.
Rideing the Bike it just feels as though there is not enough rebound dampening. I have always planed on sending them out to be rebuilt by somebody who knows what he is doing.
I have recently ridden a 83 Maico that was thrown togeather useing e-bay parts. The Forks have Race Tech Emulators, the Rear Shock was recently rebuilt by somebody who was suposed to know what he was doing. The suspension works very well just the way it is, in my opinion better than my modern KTMs. I think I just lucked out.
So what should I exspect out of my Ohlins ? We are comparing what I would consider probably as good of Twin Shock set up as there ever was, by one of the early lingage single shock set ups. Right now there is no comparison between the two.
I have always considered that the main advantage of a single shock was that they were cheaper to manufacture. KTM has just recently started useing a lingage on some of there bikes. I have always thought that a Twin Shock could be made to work ever bit as well.

 

[fran...k.]

What sort of response does your bike have when you push down on the seat and observe how fast it springs back?

I think initially a lot of the mono shock designs were quite progressive meaning that the shock moved less in the beginning of the wheel travel and more later on. This made it possible to be softer initially. As time went on it seems the linkages got less progressive. There is a weight savings in the single shock vs. dual shock, not sure how that works out when you figure the linkage, top mount reinforcement, and swing arm design. I don't think there is much doubt a single shock can be located to get better mass centralization.

I am not aware of a (non antique) motorcycle design that separates out the spring from the shock. There are some pretty impressive shocks in off road truck racing with external tubes I figure must hold damping which I would think is the most advanced stuff out there.

 

[Kartwheel68]

Every Husky I've ridden with stock valving Ohlins feel like they need more rebound damping to me. Those Ohlins are very simple and if the guy does modern shocks he should have had no problem rebuilding them since they really are not that much different.

 

[Joe Chod]

I too agree that ohlins stock valving needs more rebound dampening for MX or woods with many sand woops. Fine for snotty rocky rooty woods though and the ITC are even better than the regular ohlins. Drew Smith from WER does all my vintage stuff, has the parts, and has been doing these as a business since the "back in the day" time. Despite the fact that a modern guy should know what to do, sometimes you need to find what I call the mom and pop shop. Also...never trust a shop that does not have a shop dog or cat.

 

[Picklito]

Another option that is often overlooked is to send them directly to Ohlins USA in NC. They do an outstanding job, they have the parts, they know the shocks inside-out, and have good valving upgrades available. I'd put a "correctly done" 82 rear suspension up against any. Also, if you have early 82 or older shocks, upgrade them to the one-piece seal head while you're there. Heck, the multi-piece seal may not even be available anymore, so it might be an 'automatic' upgrade when you order the part. Drew Smith - ya - he'd definitely know what to do, too.

 

[Joe Chod]

one piece seal head is the norm as the multi pice is gone like the do-do bird (unless you find some old OEM shoebox of tuners parts)

 

[1982 XC 430]

What sort of response does your bike have when you push down on the seat and observe how fast it springs back?

I think initially a lot of the mono shock designs were quite progressive meaning that the shock moved less in the beginning of the wheel travel and more later on. This made it possible to be softer initially. As time went on it seems the linkages got less progressive. There is a weight savings in the single shock vs. dual shock, not sure how that works out when you figure the linkage, top mount reinforcement, and swing arm design. I don't think there is much doubt a single shock can be located to get better mass centralization.

I am not aware of a (non antique) motorcycle design that separates out the spring from the shock. There are some pretty impressive shocks in off road truck racing with external tubes I figure must hold damping which I would think is the most advanced stuff out there.

I will say it fails the the push down on the seat test. It feels " Springy" . I'm not sure if the Single Shock saves all that much weight, at least at first. My 83 Maico Swing Arm weighs about double what a Twin Shock Arm weighs, Granted after 82 they were trying there best to build something that wouldn't break.

 

[1982 XC 430]

I have asked this here before, but I will ask again. The Race Tech Gold Emulators seem very popular with the Vintage Forks for a lot of brands. In my rideing with them on my Maico I can see why. I plan to do a set of My Husqvarna Forks to see if they work the same. I am tempted to send my Ohlins Shocks to them and have them do there magic on them as well. I realise that when done they won't really be Ohlins any more. Any body have anything to good or bad to say about this Idea? Thanx...

 

[Kartwheel68]

Race Tech can not improve on the Ohlins other than revalving like everyone else.

 

[1982 XC 430]

By reading Race Techs web sight, I believe that they are going to rip out the OEM Valveing and install there own. It sounds as though they can do this to most any Vintage Shock, so no matter what brand the Shock is, it will end up with probably the same Valveing as a new set of Race Techs Vintage replacement Shocks.

 

[adam6402]

By reading Race Techs web sight, I believe that they are going to rip out the OEM Valveing and install there own. It sounds as though they can do this to most any Vintage Shock, so no matter what brand the Shock is, it will end up with probably the same Valveing as a new set of Race Techs Vintage replacement Shocks.

Well, we both must have read the same thing, you can be the first and let us know how they turn out.

 

[Kartwheel68]

Race Tech fork Emulators for damper rod forks are great, but there is nothing special about Race Tech Gold Valve shock valving, and it will not be better than the Ohlins parts. When Race Tech sells a "Gold valve" kit for a modern shock, what you are really buying is access to their shim stack database. The actual parts in the Gold Valve are no better than any OEM parts, but they sell you that so you feel like you are getting something for your money. For a pair of Ohlins shocks you will spend a lot of money for parts that are no better than what you have, and because its a twin shock application you wont get any benefit from the shim stack database because they only have specs for modern shocks. If you want your modern shock rebuilt, Race Tech is as good as any other modern suspension shop, but if you want vintage Ohlins rebuilt or revalved, just send them to someone who does them regularly to have them serviced, like Drew Smith, dont waste any money on Race Tech.

 

[pcnsd]

Race Tech fork Emulators for damper rod forks are great, but there is nothing special about Race Tech Gold Valve shock valving, and it will not be better than the Ohlins parts. When Race Tech sells a "Gold valve" kit for a modern shock, what you are really buying is access to their shim stack database. The actual parts in the Gold Valve are no better than any OEM parts, but they sell you that so you feel like you are getting something for your money. For a pair of Ohlins shocks you will spend a lot of money for parts that are no better than what you have, and because its a twin shock application you wont get any benefit from the shim stack database because they only have specs for modern shocks. If you want your modern shock rebuilt, Race Tech is as good as any other modern suspension shop, but if you want vintage Ohlins rebuilt or revalved, just send them to someone who does them regularly to have them serviced, like Drew Smith, dont waste any money on Race Tech.

Having rebuilt and revalved a shock or two including installations of the Racetech gold valve kits I will respectfully disagree. Technology has a habit of moving forward over time and the technology surrounding shock piston design has indeed moved. This is not to say that the Ohlins twin shocks are anything other that top of the line equipment and very adjustable. The piston design offered by Racetech however is of more recent development. The Ohlins piston is itself an advancement on the original design that used equal orifice cross sectional areas for compression and rebound. It has a larger area for compression damping. This moved the limiting effect of orifice size and placed more of the flow restriction under the control of the shim stack. (Look at some of the early Marzocchi piston/shim shocks for comparison). The Racetech gold valve is an expansion on this theme. You can do quite nicely with the Ohlins OEM gear. If you have time you may wish to try multiple stage valving similar to what came with the ITC shocks. The real limiting factor with the late Husky suspension was in front. Husqvarna did not follow the development curve with Simon and Fox and the 40mm forks leave much to be desired throughout their range. As already discussed the Racetech emulators will get you away from the temperature sensitivity and general malaise of the stock forks, but they will still be flexi.

Regards,
Paul

 

[Kartwheel68]

I dont disagree with that. I have several pairs of Marzocchi piggyback shocks on Pentons and I have messed with those shim stacks. Adding a shim or two makes a difference, but as you pointed out the shims have much less effect than an Ohlins or a modern shock. I learned to revalve shocks by installing Gold Valve kits. Every one I did I measured and cataloged the shims that came stock, the ones Race Tech said to use, and the ones I ended up liking. After a while I realized what they were really selling was the access to the shim stack database. On a modern shock there is no advantage to Gold Valves, in my opinion anyway. While there might be a slight improvement over an '82 Ohlins piston, it will be minor and I very seriously doubt it could be felt "seat of the pants" versus a good revalve of the oem parts by someone who knows what they are doing. You will not get anything like the dramatic improvement the Emulators make in a damper rod fork, which literally transforms those forks once you get them dialed in.

 

[adam6402]

Have any of you experimented with different weight shock oils? As I recall they came with 7.5 weight. I don't care for my current damping or rebound and was thinking about trying a little heavier oil

 

[Joe Chod]

you guys are all tracking. The husky 40s work different than most other forks and with the emulators and changing the hole sizes and # of them in dampner rod is it. Like said..arent paying for the product as much as for the R&D time and experimenting with shim stacks. That is why I believe the suspension guys deserve every dime. Lots of time spent by them coming up with the 99% solutions...it isnt the time they actually spend on yur compnenets. And BTW Drew has been doing some work with the emulators on the 40s on his own vintage Husky so I am gonna send him a set next week with some RT fork emulators and have him work his magic. He did my ITC's and they are awsome.

 

[pcnsd]

Have any of you experimented with different weight shock oils? As I recall they came with 7.5 weight. I don't care for my current damping or rebound and was thinking about trying a little heavier oil

Oil weights fall into some very broad viscosity categories. Literally an oil that is 7.5 wt can also be 10 wt and 15 wt. and still be within the applied viscosity range. I have used the Ohlins twin shock oil (7.5wt) and Maxima's heavy racing shock fluid (10wt) for servicing the Ohlins twin shocks with good result. I will not advise using viscosity as a tuning tool on shocks. You are better to change the valving. It is far more precise and effects only the circuit you are targeting.

Regards,
Paul

 

[Orville Story]

I have asked this here before, but I will ask again. The Race Tech Gold Emulators seem very popular with the Vintage Forks for a lot of brands. In my rideing with them on my Maico I can see why. I plan to do a set of My Husqvarna Forks to see if they work the same. I am tempted to send my Ohlins Shocks to them and have them do there magic on them as well. I realise that when done they won't really be Ohlins any more. Any body have anything to good or bad to say about this Idea? Thanx...

I have purchased the race tech Gold Emulators for my HD XR1200. It did make a difference in the damping, but the most improvement came by changing out the springs. The difference was important to me because I am 250lbs. I have ordered the same for my Husky. I am changing the springs to RT FRK SPR 33.6x521mm .50kg, stocks springs are set at .32kg which may be fine for some one that is 175 lbs.

I am still studying out the best way to deal with the rear shocks. I believe that maybe my best bet is to send them to Ohlins as Picklito suggested. I considered rebuilding them myself, but I am not confident in refilling and charging them correctly.

 

[adam6402]

Filling and charging them is the easy part, the hard part for me was getting the third internal clip out during diss-assembly.

This theead has lots of info on rebuilding them.

http://www.cafehusky.com/threads/twin-shock-piggyback-ohlins-rebuild.7450/

 

[Kartwheel68]

I am 250lbs. I have ordered the same for my Husky. I am changing the springs to RT FRK SPR 33.6x521mm .50kg, stocks springs are set at .32kg which may be fine for some one that is 175 lbs.

Just FYI, Craig Hayes, who is well over 300lbs and an Expert, uses stock fork springs with emulators. Even with his weight, those .50kg springs that Race Tech recommends are massively too stiff. I have not heard a single person who thought those springs were good, everyone said they are too stiff.