Rear shock rebuild opinions

[docc]

Suspension set-up can take surprising new turns . . .

[motowarren]

 

To see if you need a stiffer or lighter spring you need to set your sag. Setting sag tells you if your spring is too soft, too hard, or just right, based on how much free sag you have (how much the bike sags under its own weight without the rider) after you have set the race sag (how much the bike sags with the rider on board) to the correct amount. It is not something you need to guess about.

 

Checked my sag this evening and with spring set at 152MM between the adjuster rings I have about 25-26 mm sag. So I think that spring should be pretty close yes? I'm thinking a simple rebuild should do. Maybe some slight revalving. The shaft seal is replaceable isn't it?

[docc]

Not sure what you mean by "between the adjuster rings" since the one against the spring is the adjuster ring and the other is a lock ring. Yet, 26 mm is a good sag measure; on the stiff, or tight, side - could be out to 30-33 on the 'comfort' side.

 

The picture of my SACHS is 145mm from the top coil to the bottom coil, with 12mm remaining in the adjustment.

[motowarren]

Not sure what you mean by "between the adjuster rings" since the one against the spring is the adjuster ring and the other is a lock ring. Yet, 26 mm is a good sag measure; on the stiff, or tight, side - could be out to 30-33 on the 'comfort' side.

 

What I meant by "between the adjuster rings" should have been between the spring seats, top one being the adjustable ring and the bottom one being the none adjustable seat at the bottom of the shock

[docc]

Ah! We could say, then, "spring length." The one pictured is 145 mm.

 

I have edited my previous posts where I mis-measured. So, for clarity (if we could hope for such a thing ), I'll say it this way:

 

The range of adjustment is about 30mm. The shock pictured is "preloaded" 18mm or 60% of the adjustment range. (Even if the adjusters are backed all the way off, I suspect the spring still has some "preload." I could not find any specification for this spring's free length.)

 

The angle of the photo does not show the threads below the adjustor ring, but there is another 12mm to maximum.

 

I am surprised with your weight and your spring length that you do not have more sag. Possible the PO already changed the spring?

(The stock coil wire is about 0.445" with 6 full coils)

[GuzziMoto]

 

To see if you need a stiffer or lighter spring you need to set your sag. Setting sag tells you if your spring is too soft, too hard, or just right, based on how much free sag you have (how much the bike sags under its own weight without the rider) after you have set the race sag (how much the bike sags with the rider on board) to the correct amount. It is not something you need to guess about.

 

Checked my sag this evening and with spring set at 152MM between the adjuster rings I have about 25-26 mm sag. So I think that spring should be pretty close yes? I'm thinking a simple rebuild should do. Maybe some slight revalving. The shaft seal is replaceable isn't it?

Please either re-read my post or google setting sag (I take no responsibility for what results you get, though.....). The race sag alone means nothing with regard to your spring rate. You have to measure both.

After you set your race sag, how much the bikes sags with the rider on board, then measure your free sag, how much it sags under just the weight of the bike. If your race sag is around 25 - 30% of total travel then your free sag should be around 5 - 10% OTT. If it is more then that your spring is too stiff, less then that your spring is too soft. Street riders tend to shoot for the 30% / 10% OTT numbers and some racers like closer to the the 25% / 5% OTT side.

 

As for what you choose to do, it depends on you resources ($$$) as well as your requirements. The stock shock is pretty average. It holds the rear of the bike off the ground and mostly keeps things under control. A higher quality shock like an Ohlins (even a low end Ohlins is a very nice shock, they do not make cheap shocks) or a Penske is a definite improvement but if you are happy with the stocker then a nicer shock would not be required. It depends on how you ride and what you expect.

 

A shock seal is usually a pretty universal thing based on dimensions. As my Sachs cracked at the lower mount, as they are prone to doing, I did not even look to see if the seals are available but rather went the upgrade route.

[Francis Chartier]

These are good shocks, not much behind the Oehlins. The Oehlins you find in Guzzis are of the cheapest type Oelins ever made.

Send a Sachs for overhauling and you'll get back at least the same quality that others have with their cheapo Oehlins.

 

I have a '99 V11Sport.

I fit an Ohlins S46HR1C1S (retail part, not OEM part for Guzzi) with a spring choosed for my riding style and load, and found it far superior to the original Sachs.

Same for the crappy Marzocchi 40 fork, replaced with a USD 41mm Paioli fork with Ohlins springs. Paioli Fork

 

As the '99 Sport use the short frame, I change triple clamps for a 1100Sport model to gain a little more stability and I am very pleased with the results.

[motowarren]

Well guys thanks for all the advice. I sent the shock out to race tech today. When they get it they'll look it over and call me and make some recommendations and we'll go from there. I'd love to have one of those good Ohlins but I'd have to park the bike the rest of the year to get one of them. I'll let ya'll know what Race-Tech says

[Rhino1]

Well guys thanks for all the advice. I sent the shock out to race tech today. When they get it they'll look it over and call me and make some recommendations and we'll go from there. I'd love to have one of those good Ohlins but I'd have to park the bike the rest of the year to get one of them. I'll let ya'll know what Race-Tech says

 

Any updates, Motowarren? I'm looking at either an 8963 Penske, or possibly having Racetech redo the Sachs. Very curious to see how your Racetech re-do turns out. Thx.

[motowarren]

Well guys thanks for all the advice. I sent the shock out to race tech today. When they get it they'll look it over and call me and make some recommendations and we'll go from there. I'd love to have one of those good Ohlins but I'd have to park the bike the rest of the year to get one of them. I'll let ya'll know what Race-Tech says

 

Any updates, Motowarren? I'm looking at either an 8963 Penske, or possibly having Racetech redo the Sachs. Very curious to see how your Racetech re-do turns out. Thx.

 

Just got my Race-tech rebuilt shock installed yesterday and took it for a short ride. Seemed much better simply because i didn't think about the shock when I was riding. Usually the first thing I think about when I ride this bike is how bad the shock is. I hope to get a chance this weekend to give it a much more thorough evaluation. They rebuilt the Sachs, revalved it and put a different spring on. Then they preset everything before shipping for my weight which is 200lbs if I skip Pizza for a day or so. The price was $508 with shipping.

[motowarren]

Any updates, Motowarren? I'm looking at either an 8963 Penske, or possibly having Racetech redo the Sachs. Very curious to see how your Racetech re-do turns out. Thx.

 

Just got my Race-tech rebuilt shock installed yesterday and took it for a short ride. Seemed much better simply because i didn't think about the shock when I was riding. Usually the first thing I think about when I ride this bike is how bad the shock is. I hope to get a chance this weekend to give it a much more thorough evaluation. They rebuilt the Sachs, revalved it and put a different spring on. Then they preset everything before shipping for my weight which is 200lbs if I skip Pizza for a day or so. The price was $508 with shipping.

Aha, at last my RM is living up to expectation. After installing the RaceTech rebuilt/revalved rear shock it felt much better but just not right. Not balanced, not smooth. Finally I cranked the fork rebound and the compression adjusters all the way in. And cranked the steering damper 15 clicks in (tighter) and suddenly it feels like I always thought it should be, confident .Works great for me your comfort zone may vary

[Baldini]

...I cranked the fork rebound and the compression adjusters all the way in. And cranked the steering damper 15 clicks in (tighter) and suddenly it feels like I always thought it should be...

Did you check sag on the forks already?

 

KB