Jump to content

Spring rate recommendations/valving direction - 2005 RM250, rocks, whoops


Recommended Posts

The suspension on my RM250 is pretty good where it's at now, but I can't help but think I'm still really stiff on my springrates and it's causing a bit of mid-stroke harshness and deflection.

 

I'm 185#.  Wear a tool belt and camelback with 70oz water.  3 gallon tank.

 

Right now I have 0.48kg springs up front, 5.7kg rear.  Approx 100mm sag (need to measure more accurately).  About 45mm front.

 

I run about 315cc oil in the front with PC National spring tubes.  MX Tech separator valve in the rear with a 1.5mm bleed and a FC HSC spring.  Drilled out bleed port in the fork BV to 2mm or something (stockers were blind holes, didn't do anything).  Still running bleed stack with 2 face shims.  .2mm MV float with 2-stage stack.  Single stage BV clamping on an.....18 maybe?

 

The tough part is setting a bike up for a HUGE variety of conditions.  Sand, hardpack, wet rocks, embedded rocks, loose rocks, STEEP hills, sharp whoops, round whoops, slow whoops, super fast whoops, roots, jumps, etc.

 

The BEST setup I've had so far has been with stiffer comp valving on the rear, which was not terribly compliant over individual hits, but kept the bike up in the stroke and able to hammer through long uphill sections.  Removing 4 face shims introduced a lot more wallow that I didn't like.

 

Basically I want a pretty firm setup that doesn't move any more than it needs to, just enough to not deflect or kick up.

 

I'll post up the valving that I've arrived at a little later.  For now I'd just like general thoughts on the setup and the springrates.

Link to comment
Share on other sites

BV

30 (12)

28

27

26

25

24

23

22

21

19

17.2

 

Bleed 

16 (2)

15

14

12

10.2

 

MV

20 (4)

14 (temp x-over to see if I liked softer/firmer, had some bushing issues when I tried this so it doesn't mean much)

17 (4)

10.2 (2)

11.3

.2 float

 

Reb

20 (2)

19

13

18

16

14

12

11.2

 

1.6kg IC spring

 

Comp

44.2 (10)

36.15

30.1

44.2

42.2

40.2

38.2

36.25

34.25

32.25

28.25

26.25

24.3

20.3

 

Reb

40.2 (7)

28.1

40.3

38.3

36.3

34.3

32.3

30.3

28.3

26.3

 

CADJ stack stock, just using FC HSC spring - higher rate I believe

Edited by GHILL28
Link to comment
Share on other sites

Id run .46 up front and a 5.5 on the rear. Valving looks on the soft side. I'm 190-200lbs and I'm running these spring on my rm250. I ride a lot of rocks. The stock shock valving i just removed 2 face shims and 2mm smaller clamp iirc. I have rg3 smart valves in the forks,so my fork stack is a bit different.

Link to comment
Share on other sites

Are you running the stock tank?  Any gear?

 

-2 face shims and adding a different clamp is real close to where I am now with the comp stack, except for the thinner HSC shims.

 

Also, the comp stack listed above is after I removed 4 face shims.  I had 14x face shims before, and that was the setup that was a little on the firm side.  10x face shims with the FC HSC spring run at 3 turns out and 12 C and 12 R was wallowy and bouncy.

 

Remember, that separator valve adds a bit of LSC too.

Edited by GHILL28
Link to comment
Share on other sites

They stay smooth over little stuff at speed. 4 to 6 inch stuff they deflect. They don't settle much into corners which is fine with me really. Feels like they transfer rollers and whoops into the rear quite a bit though. On downhills they're worse than uphills. I think on uphills they stay in the really soft very top of the stroke especially if the rear is getting traction and pulling hard.

Link to comment
Share on other sites

Then what do you think for valving with the softer rates?

Id leave valving alone. The softer spring rates will change the feel. I would try different oil height in forks, try 100mm sag and then try+/- 5,10mm. Are you bottoming front and rear? One thing I noticed with my rm250- I could notice right away when a linkage bearing was going bad and it made the rear feel really odd. Not saying you have a bad linkage bearing..just saying the rear seems more sensitive to me than other bikes I have owned.

Link to comment
Share on other sites

Linkage/shock bearings are cherry.

 

And yes, this bike is really sensitive to small changes.  Kinda cool actually.  Could make big changes on my old YZ and it still wouldn't get through a corner with any snap to save it's damn life.

Link to comment
Share on other sites

Any thoughts on a tapered mid?  20x3, 18, 16, 14, 12, 10.  .2mm float.

 

Also, what would the shock comp be like with the first shim from the HSC stack removed (the 44.2 right after the 30)?  So it would engage the 42 for HS instead.  Is that 44.2 making it softer or firmer versus not being there at all?

Link to comment
Share on other sites

I agree with mog.  I think that a tapered mid is good, I don't know why some of these older bikes have weird non-tapered mids.  I think you can get the same damping from a tapered and non-tapered mid, but I think that a tapered stack is much better for the shims and less likely to destroyed/deform them.  It's also a function of maximum lift, backer size, and some other things, but it helps.

Link to comment
Share on other sites

  • 6 months later...

Any thoughts on a tapered mid?  20x3, 18, 16, 14, 12, 10.  .2mm float.

 

Also, what would the shock comp be like with the first shim from the HSC stack removed (the 44.2 right after the 30)?  So it would engage the 42 for HS instead.  Is that 44.2 making it softer or firmer versus not being there at all?

Did you ever find a good shock setting? I have an 06 rm125 shock on my 05 rm250 and can't seem to get it tracking nice in the rocks. The front I had to open mid float and flipped bleed stack. Front feels good but now the rear feels terrible/unbalanced. I removed face shim from comp and clamped to a 19x.25 but I'm still all the way out on hsc and LSC. If I go in a couple clicks on either a it gets way too stiff. If I go in on rebound on the rear-it packs. I like the rebound and have good adjustment,but compression is too firm. Think this 06 shock is stiffer than 05 (bigger shaft?). Thinking of dropping 38-19 high speed shims down .5mm thick on each shim. I have them from an ohlins shock I had that busted. My other thought was to take the whole stack from the online shock and use it,but the low speed/face shims are way different stack. If I post both stacks would that help determine? Really liked the online shock but rebound needle busted. Everything was good for me with that shock

Link to comment
Share on other sites

May have found my problem-too soft. Kept going in on hsc and LSC and it started feeling good. Had to go in 4 clicks rear on rebound and 6 front and it calmed down. Feels more like the old ohlins shock now.

Link to comment
Share on other sites

Yeah these shocks generally do not react well to open HSC settings.  It affects mid-speed and initial feel WAY more than it would lead you to believe.

 

I ended up running a fairly stiff spring (5.7kg, 3g tank, 185lb + gear) and a rebound separator valve in my RM250 shock.  If you're using the RSV, best to drop the clamp shim 1 or 2mm to get the total aperture on really fast hits back to normal, and keep similar low speed shims.  Every time I tried going looser on the low speed shims to compensate for the RSV, it got wallowy and the handling benefit disappeared.

 

 

I found that open float/soft mid settings on this bike make it scary on soft downhills.  The bike has so much front end bias that in those situations the loose stuff would catch the front wheel and pull the front end down and to the side real fast.  

 

The longer than normal swingarm calls for a slightly stiffer spring in the rear, more leverage.  The longer swingarm also calls for a stiffer front spring from the front end bias.  I was running 0.48kg front, tried 0.46kg and thought I was going to kill myself, and realistically think a .50kg would be workable.

 

 

That bike is out of commission right now anyway getting the cases repaired.  Been riding my '14 YZ450F which handles worlds differently than an '05 RM250.  It will take inside lines easy though which is a good step for Yamaha.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...