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12’ KTM 350 Shock- Bleed Hole or Not?

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I have been working with the rear shock of my KTM350xcf. 6.2mm/kg spring, bladder conversion and racetech piston ban. On stock, I bottomed a lot and the bike tended to float around alot (lot of movement for what you would think should be nothing). I stiffen up both the compression and reb stacks as a first try (stack labeled 1/12/2013). On rebound stack, extra 0.25 and 0.3 face shim and one size larger clamp resulted in unridable rebound characteristics. Very very slow on low speed rebound. The ride was so bad, it was hard to evaluate anything else, but the LS compression felt very stiff too.

So I put in stack 1/13/2013. Slightly lighter compression and rebound stacks versus mod. This was workable. With this stack, I have settled on –

LS comp out greater than 14

HS comp out 1.75 turns (to be sure on this one I need to test more)

Reb out 15

It seems that the LS comp adjuster makes no difference after 12-16 out.

I think I like the effects of the extra rebound shim on rebounds from deeper hits. The LS compression still seems to be a little to stiff for my taste and as stated above, the adjuster seems to make no difference past 12 to 16 out.

So, I have read the threads about the WP piston design, and am considering drilling the piston. It seems to me that a lot of what I think of as LS bleed comes from the shims opening up on this WP shock setup and not as much through the rebound needle circuit. I assume that drilling a bleed hole would allow one to get more LS movement on the compression side without having to run lighter stacks like stock.

So I guess the question is, is drilling a bleed hole the correct direction to take in my situation? And if so, what size? I see recommendations from 1.2 to 1.5mm.

Thanks for your input.

Stock 1/12/2013 1/13/2013

COMP

(5)44x.2 (7)44x.2 (7)44x.2

36x.15 40x.2 36x.15

26x.1 36x.15 30x.15

44x.2 44x.2 44x.2

42x.2 42x.2 42x.2

40x.2 40x.2 40x.2

36x.2 38x.2 38x.2

34x.15 36x.2 36x.2

32x.15 34x.2 34x.2

30x.15 32x.2 32x.2

28x.15 30x.2 30x.2

21x.25 28x.2 28x.2

26x.2 26x.2

24x.2 24x.2

22x.2 22x.2

20x.3 20x.3

REB

(3)40x.2 (3)40x.2 (3)40x.2

28x.15 (1)40x.25 (1)40x.25

40x.25 40x.3

38x.25 28x.15 28x.15

36x.25 40x.25 40x.25

34x.2 38x.25 38x.25

32x.2 36x.25 36x.25

30x.2 34x.2 34x.2

28x.2 32x.2 32x.2

20x.3 30x.2 30x.2

28x.2 28x.2

21x.3 21x.3

COMP ADJ STK STK

Edited by Phil_S

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I wouldn't use a bleed hole but you could always try it and epoxy it in afterwards. Your std stacks look very strange, nothing like what i've found in euro models. U found that comp stack as it were?

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Good luck trying to post stack info on this crap board software...

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If it's an 11 or 12 you gotta get into the dcc and modify

Is a stock piston as well??

The port area is so large it's like a light switch

Once the shims start to deflect it cannot control the port area at all

I would recommend changing the piston

Regarding bleed holes if you're riding woods and technical stuff yes it helps with traction a TON!

Rebound I use this stack a lot with a 1.00mm bleed but with a showa piston

Clicker start around 10 to 12 out

40x.25

(3) 40x.20

28x.1

38x.2

36x.25

34x.25

32x.25

30x.25

28x.25

26x.25

21x.3

Edited by ds1434

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OK, thanks for the help.

Yamaha837- The stack is stock for my 12' 350xcf

ds1344- Yes 12' 350xcf. Offroad only.

I think I will drill and put in a ligther spring in the compression adjuster stack. Seems to me that the HS compression adjuster is a very coarse adjustment. You can make the bike ride very stiff with screwing in the HS adjuster. Seems like it should have a ligther effect.

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OK, thanks for the help.

Yamaha837- The stack is stock for my 12' 350xcf

ds1344- Yes 12' 350xcf. Offroad only.

I think I will drill and put in a ligther spring in the compression adjuster stack. Seems to me that the HS compression adjuster is a very coarse adjustment. You can make the bike ride very stiff with screwing in the HS adjuster. Seems like it should have a ligther effect.

I would modify the dcc valving to a bit stiffer than 13 specs and then keep the oem spring

Try this

22x.25

16x.1

20x.2

18x.2

16x.15

14x.15

9.5x.3

Should feel a really good usable range

If you went to the older style spring cup you could go with a lighter spring

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I would modify the dcc valving to a bit stiffer than 13 specs and then keep the oem spring

Try this

22x.25

16x.1

20x.2

18x.2

16x.15

14x.15

9.5x.3

Should feel a really good usable range

If you went to the older style spring cup you could go with a lighter spring

is the c.adj. valving that different from the MX model? wow, that is super soft. but the mx has a bleed.

I have the following stack in my ktm sx

c.adjuster 20x010 2x22x025 20x025 18x025 16x025 14x025

10x030

could you please give me your stock valving. thanks

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The 13's have all .15's!! And a bleed! While I have not tried the all .15 stack Russ said it 's very compliant but once you get past one turn out on the hs goes to crap.

The last five or six 2t xc's i've done i used the stack i listed with good results.

The oem 12' xc dcc stack is this:

(3)22x.25

20x.2

18x.2

16x.2

14x.2

9x.3

This gives the shock a bad spike with pretty much any main piston valving

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OK, thanks everyone for the advice.

I drilled a 1.5mm bleed in the piston and have to say after trying it, I see it as a must do thing if you are going to stiffen up the rebound stack. I also put in a modified comp adjuster stack close to recommended above with a crossover and 0.75mm spring preload with the HS comp adjuster full out. I still need more testing on this.

Concerning the bleed hole, with a beefed up rebound stack, the bleed hole puts the LS compression back in a reasonable range and I am happy about that.

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