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Stock fork pressure springs?

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Cant find what the stock fork pressure springs on a crf 250 2013 is.. Looked at racetechs web site, but cant fint it. Anyone who knows?!

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I found the stock springs they list aren't always accurate.  Isn't the R designed for a 160 lb person?  In that case, what you have should be fine.  Your sag is pretty much spot on.  If you have harshness, then you may just need to replace the fork fluid and rebuild the shock, or play around with your clicker settings.

 

The manual says 0.45 kg/mm and 5.3 kg/mm for the stock spring rates.

Edited by mossman77
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Stock pressure springs are 1.9

Thanks susco64! I can se that racetechs site often suggest very soft springs?! It says 5.0 rear and 0.42 front for my 74kgs...

Sounds terrible soft for a bike that heavy!? Sag measurements is spot on with stock 5.3 shock spring, so I think it's funny their suggestion is 5.0 for the rear. The question is, could I even get the sag right with such a soft spring.

I will tare the forks down and change the fluid, and remove 4-5 face shims from the base as a start.

How will removing the 4mm pre load ring in the forks affect the fork and handling?

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Thanks susco64! I can se that racetechs site often suggest very soft springs?! It says 5.0 rear and 0.42 front for my 74kgs...

Sounds terrible soft for a bike that heavy!? Sag measurements is spot on with stock 5.3 shock spring, so I think it's funny their suggestion is 5.0 for the rear. The question is, could I even get the sag right with such a soft spring.

I will tare the forks down and change the fluid, and remove 4-5 face shims from the base as a start.

How will removing the 4mm pre load ring in the forks affect the fork and handling?

I assume you're a woods rider as removing that much from the base is a big change for mx.

Not sure what you mean by 4mm preload ring.

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I'm no suspension expert but from my understanding, replacing these alters

at which rate the cartridge builds internal pressure to combat cavitation.

 

Stock ICS cartridge pressure springs are often in the 1.9kg/mm range

Race Tech lists: 1.0, 1.4, 1.8 & 2.2kg/mm aftermarket ICS springs.

In my opinion the 1.8 are too close to see a difference if your OEM springs are in fact 1.9's

and the 1.4 too light for a 250F if you ride MX / big jumps or weigh more than 160lbs.

 

A softer ICS spring may initialy be plusher say for trail/off-road/enduro but in the event of a large / sharp hit (motocross)

the fork will have to travel further in the stroke before enough internal pressure is built up to stop cavitation of the fluid.

Cavitation of the fork oil (think air bubbles) means loss of dampening and simply blowing thru the stroke.

So unless you are very light (less than 150lbs) I don't think it's wise switching to a softer ICS if you ride motocross/hard landings.

 

The ICS spring isn't usualy preloaded on stock forks so that the first inch or so of wheel travel can more

easily 'follow' with a certain plushness rather skip over rough terrain without any internal cartridge pressure build-up.

The ICS spring is actually often installed 'loose' in the compression valve assembly with perhaps up to 4-5mm of free play before it makes any contact.

In the intend of firming up my fork's initial travel (ride higher) but still have some plushness/dampening control I have started experimenting with preloading a softer ICS spring,

(not actual preload but rather setting it with no free play) but can't yet give you my impressions as the MX riding season is over here until next spring.

 

Preloading the main fork springs only affects ride height / sag, standard preload is usualy set at about 4mm

too little preload and the spring will be loose/rattle inside the tube at full extension, too much preload will make for a harsh ride.

On many forks you simply increase preload by adding the proper washers in the bottom tube where the main spring sits,

depending on fork model/design, if despite no washers there's still too much preload you can reduce it by having the spring perches machined down a few mm's.

Edited by mlatour

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Stock ICS cartridge pressure springs are often in the 1.9kg/mm range

replacing these alters at which rate the cartridge builds internal pressure to combat cavitation.

Race Tech lists: 1.0, 1.4, 1.8 & 2.2kg/mm aftermarket ICS springs.

In my opinion the 1.8 are too close to see a difference if your's are in fact 1.9's

and the 1.4 too light for a 250F if you ride MX / big jumps or weigh more than 160lbs.

A softer ICS spring is initialy plusher say for trail/off-road/enduro but in the invent of a large / sharp hit (motocross)

the fork will have to travel further in the stroke before enough internal pressure is built up to stop cavitation of the fluid.

Cavitation of the fork oil (think air bubbles) means loss of dampening and simply blowing thru the stroke.

So unless you are very light (less than 150lbs) I don't think it's wise switching to a softer ICS if you ride motocross/hard landings.

The ICS spring isn't usualy preloaded on stock forks so that the first few inches of wheel travel can 'float' over rough terrain

without any internal pressure pushing down on the wheel, the spring is actually often installed 'loose' in the compression valve

assy with perhaps up to 4-5mm of free play before it makes any contact.

In the intend of firming up my fork's initial travel (ride higher) but still have some plushness/dampening control I have started experimenting with preloading a softer ICS spring,

(not actual preload but rather setting it with no free play) but can't yet give you my impressions as the MX riding season is over here until next spring.

Preloading the main fork springs only affects ride height / sag, standard preload is usualy set at about 4mm

too little preload and the spring will be loose/rattle inside the tube at full extension, too much preload will make for a harsh ride.

On many forks you simply increase preload by adding the proper washers in the bottom tube where the main spring sits,

depending on fork model/design, if despite no washers there's still too much preload you can reduce it by having the spring perches machined down a few mm's.

I ride only mx! But in Sweden, where I live, almost all tracks are small technical ones with tight turns and not alot of big jumps.

I like my forks to be on the soft side.. I liked my crf 250 from 2010. It was softer and worked great on our tight tracks over seas.

The shim stack on my 2013 looked like the great pyramid of Gisa in comparance with the 2010 stack. Thats why I thougt about remove some face shims.

I hate to ride the chopper style suspension set up!

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