Rgs Rear Shocks

No way am I suggesting that Cosi's info is suspect, just confirming it. The other week I was up on Bell's Line of Road for the fires, they wanted to light up the bush at the bottom of the cliffs to form a fire break. Found some old bottles and half filled them with drip-torch fuel (part diesel and part petrol) and cut up an old face cloth for wicks. We moved on before we could use them, leaving a couple of Molotov Coctails by the side of the road with my fingerprints and DNA all over them. Still waiting for the knock on the door :( :(

Better get back on topic ::)
 
Phew, thank God for that. I wouldn't be able to live with the shame :D
 
Powder coating?

I picked the frame up from the painter. Do you not understand the concept of paint?
You'd better start getting some brain cells working if you want to pass the DHOTY mantle to the next bloke.  :D


 
Dellortoman said:
You'd better start getting some brain cells working if you want to pass the DHOTY mantle to the next bloke.  :D
Click to expand...

Whatever.... (I hate it when my kids dismiss me with "whatever".....)

I gotta strap it to the rack to get it to Cosi's place, should be fun as it weighs about 2.5 tons!
 
Scored a pair of very slightly used Sachs shocks for the RGS. They are 360mm long, have adjustable rebound damping, and have 12mm eyes so I'll have to make 10mm bushes for them if they end up on the RGS. They'll bolt straight onto the Jota (12mm bolts) so I'll be able to give them a road test at the weekend.

Cam
 

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Standard length is 362mm. So 2mm is bugger-all in the scheme of things. Eating a good lunch could compress the suspension that much.  :D

Besides, I've already shortened the trail by around 5mm with the BMW forks/yokes, which is equivalent to jacking up the rear by about an inch, so I really don't want more height in the arse end at this stage.

The shocks were a good price, so I figured they'd be worth a try. I don't know much about Sachs shocks. I think they were fitted to some Japanese sports bikes. It'll be interesting to see how they feel.  Surely they've gotta be better than the old non-adjustable Konis on the Jota.

Cheers,
Cam
 
Dellortoman said:
Standard length is 362mm. So 2mm is bugger-all in the scheme of things. Eating a good lunch could compress the suspension that much.  :D

Besides, I've already shortened the trail by around 5mm with the BMW forks/yokes, which is equivalent to jacking up the rear by about an inch, so I really don't want more height in the arse end at this stage.

The shocks were a good price, so I figured they'd be worth a try. I don't know much about Sachs shocks. I think they were fitted to some Japanese sports bikes. It'll be interesting to see how they feel.  Surely they've gotta be better than the old non-adjustable Konis on the Jota.

Cheers,
Cam
Click to expand...

Hi Cam

never seen motorcycle shocks from Sachs.

Sachs makes really high end shocks for cars. Typically the Sachs ride a little "plusher" than Bilsteins, which are usually way firm. I just bought another set of Sachs rear shocks for my old Jag about a month ago, found them on sale for 1/3 their usual list price, $100 each vs their usual $300 +, so got a pair through www.autopartsway.ca for $200 plus shipping rather than the usual $600 +

Koni shocks for the same application of my old Jag are about $80 each, and total crap.

I will have to look into Sachs for motorcycles, I really like them for various of my cars.

Paul LeClair
 
Sach make the single shock on my 05 TE 250 Husky,no complains,the TC unregisterable MX version came with an Ohlins shock.No idea why the difference,you can set up shocks to do anything.Both had piggybacks so fade from heat isn't it.maybe the Ohlins ran a bladder and soaked up the little stuff better but thats more important in Enduro.Don't have a clue.Anyway no leaks or problems with my Sach.
 
The Sachs stuff usually works quite well. They also are used as OEM parts on a lot of enduros and I believe Aprilia was installing them for many years if not still doing so today.

Tom
 
From what little info I could glean from the web, Sachs shocks seem to be towards the higher end of the suspension market. Bikes like Ducati and MV Agusta come with them as original equipment. Mostly monoshock these days but some "retro" models like the Ducati 1000 Sport Classic has Sachs twin shocks.

I bought them from Steve Wood at Suspension Improvements. He said these particular shocks would normally be fitted to something like a Kawasaki ZRX 1100.  I've always found him pretty good to deal with and I'm sure he'd be happy for me to return them (and buy something more expensive) if they don't suit the bike.

Cam
 
I put the Sachs shocks (destined for the RGS track bike) on the Jota and took them for a road test today.

General impression is not bad at all. Damping seems to be an improvement over the Konis that normally live on the Jota.

The arse-o-meter is a bit of an inaccurate tool (my arse hasn't been calibrated) but the back wheel seems to follow the lumps and potholes in the road without breaking contact. There was a bit of rear wheel chatter under heavy braking. But I dialled up the rebound damping a few clicks and pretty much eliminated that - something I've not been able to do with the Konis (they're early Konis without the click adjuster).

The arse end feels a bit stiffer with the Sachs. I suspect that might have more to do with the compression damping than spring rate because the rider sag is in the same ballpark for both shocks. I don't have any numbers for spring rates or damping so these comments are pretty much subjective.

Here's a few rough comparisons:

                                      Koni                              Sachs
Eye to eye length          362mm                          359mm
Springs                          Constant rate                Progressive
Static sag                      20mm                            10mm  (not as much pre-load on the Konis)
Rider sag                        10mm                            10mm  (spring rates about the same)
Compression damping    Softer                            Harder
Rebound damping          Soft (non-adjustable)    Adjustable to a better setting to dial out rear wheel chatter


Even though the Sachs shocks are slightly shorter in eye to eye length, the rear ride height was a bit higher because of the higher pre-load setting on the springs. I didn't realise this until afterwards when I put the Konis back on the bike. The pre-load on the Konis is on its lowest setting because the bike handled better that way with the previous tyres on it. I've since fitted new tyres but haven't thought to change the pre-load. Steering felt OK with the Sachs shocks, so I could probably crank the Koni pre-load up a bit.

Cheers,
Cam

 
Cam,

You can alter/regain the rebound damping of your old Konis easily.

Remove the spring, top fixing eye and compression stop rubber.  Push in the damper rod as far as it will go and turn it while applying downward pressure.  You will feel it engaging in the bottom of the damper with it slipping in further a couple of mm.  You can now adjust the rebound damping by turning the valve in the bottom of the damper body.  Don't remember if you can feel "clicks" or not, just use your judgement in the end.  IIrc, the rod goes through 3 revolutions from one end of the scale to the other.

This method was incorporated to compensate damper wear and the associated deteriorating rebound damping.  The dial-a-rides simply had this feature moved to the exterior... bingo, modern adjustable dampers!  Koni Special D dampers had this feature from the beginning.

piet
 
Thanks Piet. I was aware of that feature, but don't know which way to turn the damper rod. OK, I could look it up on Google, but it's a lot of hassle taking the shocks off, dismantling them, adjusting, reassembling, reinstalling, then road testing only to find I've turned the bloody thing the wrong way, or too far the right way. Then having to go through the process again. So I've never been motivated enough to do it.

Road testing suspension for me means going to my "control" bit of road that has lots of bumps, corners, and bumps in corners. It became my standard road test track when I lived nearby. I live about 15km away now, but I still use that bit of road because it's a known baseline for comparison.

Maybe I need to find a closer bit of badly maintained road.  :D

Cam
 
      I have been doing some Stealbay studying and it seems the Yamaha XJR1300 come with Ohlins (of sorts) fitted, they are pretty common on there down to ?200 a pair second hand. 324-334mm eye to eye, the Kawasaki 1200 & Honda 1300 all are around the same sizing. Ok these bikes are heavier but by how much? It came from earlier in this thread where the shocks were originally listed for one of the above, just a thought. :-X
 
334mm eye to eye is too short for a Laverda. If you were to use shorter shocks, you'd need to make up some kind of adapter to change the centre distance between shock mountings.

Cam
 
z1300 of same period as Laverda do have the same shocks (or a little bit longer...) as the Laverdas. I purchased a set of Wilbers made for a Z1300 and they fitted (except for the mounting holes) perfectly. Good thing is that the mounting holes on the Wilbers can be altered easily by exchanging some alloy parts. If you have a friend with a lathe, that is a 10 minutes job to get some made... (you need 4 of these).
 
I put a set of Race Tech GS-3 shocks on my RGS. Preload and height adjustable with rebound adjustment as well. I went with 14.75 inches eye to eye, or 375mm. Picked up the back and end and gave me sharper steering. Extremely nice and handmade in the USA. Not cheap at $850 US (you can get them a little cheaper if you delete ride height and rebound adjustment) but I think they're worth it; the ride and control is excellent. I also rebuilt the forks with Race Tech cartridge valve emulators and new 0.90kg straight-rate springs, highly recommended as well.
 
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