crf 250 2010 suspension issues

I recently bought a crf 250 2010. I really like the way the engine performs, but not happy with the suspension:foul:.

Forks works very well in the fast sections of the track with small bumps:ride:.

But not when hitting the medium sized bumps. I can't really say if the forks dive to low in every bump, but I think so.

In small fast bumps the forks, as I said, have a good grip, but the rear feels a bit bumpy. I notised a small improvement by clicking the rebound clicker in 3 clicks from what the book suggest, and the LS compression clicker out 2 clicks.

I'm 82kg in my gear, and a intermediate rider....

Shock is stock everything and sag is 105mm

Forks are 0,45Nm springs (stock 0,44), oil ammount 330ml and revalved this way...

16-32.1 (5 removed, I think)

30.1

28.1

26.1

24.1

22.1

20.1

18.1

16.1

8-14.2

4-12.2 (Must be added to prevent the nut from bottoming?)

Base Plate: 20mm x 1.65mm

4-12.2

Mid

Comp

4-20.1 (one added)

18.1

16.1

14.1

12.1

11.1

2-11.3

2-17.3

Reb (stock)

4-20.1

12.1

20.1

18.1

16.1

14.1

2.12.2

Any ideas just by looking at the shim stacks?

Mr P

sounds like too much weight on front wheel , some use a lowering link on the rear of the 250 to stop this , you could go up a rate in springs in the forks , what's your free sag on the rear and try to measure for sag as well , with the extra shim on the mid and softer base it should not blow through the stroke

we are testing one today. the rider will be adding a link to the rear. sdi makes one, and so does pro circuit, fc and so on.

we tightened up the float to .15

that bike really was like a stink-bug. we ran the same sag 105, then 108. the rider swapped out springs. he's running .46kg's up front, and a 4.9 in the back.

sag numbers are within the spec we like to see.

I measured the sag again after posting the thread.

Actual sag was 99/28, changed to 105/31 now, maby I should go with a 5,0 rear spring?

Mr P

I would imagine that the current spring rate is optimal based on your free sag numbers.

yes it's good

we are testing one today. the rider will be adding a link to the rear. sdi makes one, and so does pro circuit, fc and so on.

we tightened up the float to .15

that bike really was like a stink-bug. we ran the same sag 105, then 108. the rider swapped out springs. he's running .46kg's up front, and a 4.9 in the back.

sag numbers are within the spec we like to see.

What means tighten up the float? And how do that affect the damping?

Mr P

What means tighten up the float? And how do that affect the damping?

Mr P

More than likely the float was tightened with that added 20.1 to the mid valve.

Your valving looks close and that 20.1 in the mid was a must do.

You need a rear link. Start with 340CC... then add to control bottoming if needed. Set clickers at C5-10 R10.

when adding shims under the clamp try to make them bigger than the clamp, its unlikely the 14.2(*) are bending but you dont want variables, you could put the 32.1(5) there instead.

The faster the rider, the stiffer front springs I have been running than "normal".

And on all bikes i lower the rear internally 3mm.

Sag around 105.

One example is a local A rider I am running .50 front fork springs he only weighs 170 with no gear...so clearly a little on the stiffer side of normal - but prior with .47s and stiff valving it was not enough. This way we could back down a tad bit on the valving and still hold up the front end under heavy braking.

the stiffer fork springs do help with the braking for sure. when i first got a hold of this bike and tested the springs, i couldn't believe they were .45's.

the float was the only thing i changed at the time of the spring swap.

too windy for track yesterday, we are hoping to test this week.:smirk:

more preload , +3 or 4mm helps also on the CRF (450 +250).

:smirk:

have you used the nylon spacers at the bottom of the tube? i have found them in some sets. could be used to help spring twist? they were about 2mm thick.

the springs i got from diverse did have some added preload spacers.

i had a set of the tunable spring seats from sdi, and installed them as well. drilled out for the fast mx specs. they're much shorter than the nationals you find in the pc stuff.

i used 350cc of oil.

:smirk:

have you used the nylon spacers at the bottom of the tube? i have found them in some sets. could be used to help spring twist? they were about 2mm thick.

the springs i got from diverse did have some added preload spacers.

i had a set of the tunable spring seats from sdi, and installed them as well. drilled out for the fast mx specs. they're much shorter than the nationals you find in the pc stuff.

i used 350cc of oil.

on my forks, i use pvc tubes instaed the stock spring seat stopp.

so its easy to change the preload and i can run different springs (longer KXF Springs etc.)

on the KYB Forks its a bearing on the bottom for the spring twist.

do not use spacers on the top of the Spring (Oilflow!)

:smirk:

on my forks, i use pvc tubes instaed the stock spring seat stopp.

so its easy to change the preload and i can run different springs (longer KXF Springs etc.)

on the KYB Forks its a bearing on the bottom for the spring twist.

do not use spacers on the top of the Spring (Oilflow!)

Depends on the spacer - the ones he mentions are above the small DIA of the spring seat - aka no added restriction.

you could use spacers that do restrict oil to act like sx seats?

yep the spacers are on top of the spring seat.

found the nylon spacers that came out of a set of forks. fac. connection sells them. they were cool about selling these. they are not posted on their site.

they are 1.5mm and 2.5mm in thickness, and go on the bottom of fork.

i'm still trying to locate a suitable thrust bearing to use when i test spring rates.

i found some for the fork springs, but the shock is a little tougher. may have to order one of the kits they sell for the shock springs-all balls?

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