Fastace bs-33ar rear shock

[Sidney]

My friend bought one of these shockers yesterday and it came with NO air in it. It has a valve to pump it up. The shock is so soft it bottoms out when you sit on it.

What pressure does he have to "inflate" it to to make it firm?


Cheers, sid

 

[cass38a]

What rating is the spring on that shock and what type on swingarm has he got?

 

[Sidney]

I don't know the rating but he's got a mono swingarm

 

[Sidney]

This is the shock

MSO Motocycles - Fastace BS-33AR-280L

 

[cass38a]

Lack of research before purchase is his main problem, that shock has only got a 550lbs spring no wonder he is bottoming out.

 

[Sidney]

No he has no air in it

 

[Maylands Performance]

The easiest way to check if the shocker is still gassed is to remove the shock from the bike,remove the spring and compress the shock.If it returns it has gas in it ,if it remains compressed the gas is gone.If the gas is gone get your local motorcycle or suspension shop to check the pressure and re-gas !!!
No biggy just annoying !!

Cheers brian

 

[jacko]

does it have any nitgren (spelling) in it that could be a start

 

[Sidney]

Alright cheers MPE I'll ask him on msn later

 

[cass38a]

For some reason in Australia we dont actually know what a shock absorber is and have them confused with a damper (on motor bikes you buy them as one unit so the confusion is understandable but on a car it is just dumb).

The spring is the real "shock absorber" and actually absorbes the shock and supports the wieght of the bike and rider.

The damper which is the bit containing the oil and gas (inside the spring) is there to reduce the speed that the spring compresses and rebounds (so it dosent feel like a pogo stick).

I would bet lefty that the spring is way too soft and the damper is probably fine.

Do what maylands performance suggests to check the damper/shock

 

[msomotorcycles.com.au]

Lack of research before purchase is his main problem, that shock has only got a 550lbs spring no wonder he is bottoming out.

Sorry cassa that was my fault and thanks for noticing that. I've changed the spring rate to what it should be 1000lbs and Brians right or you could try running around 100psi in it to see if it makes the difference you are looking for.

Ride Safe

Ken

 

[cass38a]

Sorry cassa that was my fault and thanks for noticing that. I've changed the spring rate to what it should be 1000lbs and Brians right or you could try running around 100psi in it to see if it makes the difference you are looking for.

Ride Safe

Ken

Ill peel out then

 

[cass38a]

I just realised that I bet my left nut that that spring was too soft. I hope you dont mind if I keep it now that Ken has admitted that it was his fault LOL.

 

[dirttau]

the spring rate is fine//////Fastace BS-33AR-280L

Durable Design
Rebound Damping Adjustment
Easy Turn Spring Pre-Load
Nitrogen-Charged
Oil damping with Internal Floating Piston
Service Friendly
280mm eye to eye
1000lbs spring

 

[Juls]

Any Fastace shock with a air valve will require air in the shock,

each shock is slightly different in it's requirement of air pressure.

The shock can use Nitrogen, or Air, Nitrogen is preferable, it doesn't compress as easily and it won't heat up. Air can be used, but it must be put into the shock using a proper SHOCK PUMP.

the chamber inside the shock is TINY, a shock pump will pump in VERY small amounts of air with each pump, and can handle very high pressures and read them accurately.

it is important to relise, that Overpressurisation of the shock WILL BLOW IT'S SEALS OUT!!

the Fastace 33AR I suggest running 50-80psi, I have run 140psi in one and it resulted in blown seals. (on both occasions)
The seals won't blow immediately, they will blow after 1-5 rides.
keep in mind, if you put in 100psi, as ths shock compresses the pressure inside the shock increases by 10 or more times that amount!! with 100psi in the shock, on bottom out the shock could be holding in excess of 1000psi, Depending specifically on How "Fast" the shock is compressed.

the Fastace 33AR requires air in it for the Compression circuit to operate correctly, without air pressure, then the oil inside the shock can move too freely, which in turn creates a soft saggy feeling shock, that bottoms out easily.

the Air pressure compresses the oil inside the shock, in turn allowing the compression circuit to operate correctly.

increasing the air pressure, will have a mild effect on sag, it will have a dramatic effect on the bottom out resistance of the shock as it increases the end stroke compression damping effect. As well as increasing the compression damping overall.

Unfortunatly it's near impossible to find out the exact specifications of the air pressure requirements of these shocks, the only information I have found, relates to the "air sprung" shocks from Fastace, which are used on there mountain bike shocks, I have seen this information INCORRECTLY LISTED against there coil sprung shocks for pitbikes on the internet by so called reputable sources.

You may notice a knocking sound of your shock when it doesn't have pressure inside it, it is possible to do severe damage to your shock, if you run it without air or nitrogen pressure in the shock.

I suggest either getting some nitrogen put in the shock, by a qualified motorcycle suspension mechanic, or obtaining the use of a quality shock pump (like the fastace one, or Rock Shox/Fox/Progressive suspension mountain bike ones) and carefully putting a medium amount of air in the shock.

Hope this helps.
Juls