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Showa 43mm conventional '97-'99 DR350SE Forks

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Got a few questions about a shim stack for a 1999 Suzuki DR350SE…

Its got Showa 43mm conventional cartridge forks up front with ridiculously soft stock springs(.39 IIRC) and near zero rebound control(rebound adjuster turned all the way in to get even close to decent rebound).

Goals: Capable all purpose CA plated bike(no Motocross though). Typical Southern California trails to include desert, single track, some whoops etc. Rider experience level is getting better, somewhere between novice and intermediate. It will spend some time loaded out on longer trips, and I weigh in at 205 or so geared up.

I have Eibach 996 series springs in .48 for the front which are lighter than what Racetech recommended online(.51), but were in line with what others recommended, maybe even on the heavy side, but the bike is not by any means light with a full Clarke 4.2 gallon tank…

Upon disassembling the forks I discovered that the compression valves are actually look like they will have good flow characteristics and should be worth working with before trying gold valves.

Here is the planned shim stack(all 6mm ID):

OD Thickness

17 .15

17 .10

17 .10

10 .10

17 .10

17 .10

15 .10

13 .10

12 .10

11 .10

10 .10

Does this seem like a good starting point?

Last question is regarding rebound control. Obviously with the stiffer springs I need to figure out how to control rebound better. I looked at the rebound piston and discovered it has three small (~1.00mm)bleed holes in it which allow fluid to bypass both the shim stack and the rebound adjuster. My gut feeling is that there is just too much unregulated fluid flow to control rebound and that plugging these approximately 1mm diameter holes would make the rebound adjuster functional? Total cross sectional area of the three holes is nearly the same as the orifice entrance for the rebound adjuster oil passage…

I will post up the rebound stack and pictures of the rebound (mid?) valves later today.

Thank you very much for your help!

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Got a few questions about a shim stack for a 1999 Suzuki DR350SE…Does this seem like a good starting point? QUOTE]

Not a bad start but I not sure I would use 2-17 x .10 after the crossover. On the rebound check to see if they have a bleed shim between the piston face and the first full face shim that would cover the piston ports, if so, remove it.

Post the rest of the stack and we will know better if the 3 small bleeds should be closed off.

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Sorry for the delay, but here is the pertinent info from the rebound stack...

From the piston:

OD (thickness)

17 .10

17 .10

8 .10

17 .10

16 .10

15 .10

14 .15

13 .15

9 .20

12.5 2.65 Large Clamping Washer.

DSC00358.jpg

These are the bleed holes in the rebound piston. With the stock .39kg/mm spring the forks are horrible for rebound control, so imagine they will get worse with a .48 spring.

DSC00356.jpg

What should I do about the rebound stack and the holes in the piston(valve)?

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I looked at the rebound piston and discovered it has three small (~1.00mm)bleed holes in it which allow fluid to bypass both the shim stack and the rebound adjuster. My gut feeling is that there is just too much unregulated fluid flow to control rebound and that plugging these approximately 1mm diameter holes would make the rebound adjuster functional? Total cross sectional area of the three holes is nearly the same as the orifice entrance for the rebound adjuster oil passage…

yes, close them. some pistons have one 1mm orifice, 3 is too much. like you said, too much bypass

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Thank you both for your help and advice!

with regards to the compression stack, should I delete the both the 17mm shims after the clamping shim, or just one?

Regarding the bleed holes, what is the best way to close them?

Was thinking that with a 0-80 tap, some screws could be screwed in with loctite and trimmed flush?

Or can I remove the sealing band(teflon?) and solder them up?

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with regards to the compression stack, should I delete the both the 17mm shims after the clamping shim, or just one?

Do you mean clamping? or crossover?

Regarding the bleed holes, what is the best way to close them?

I turned a copper rivet on a lathe

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Does the rebound shim stack look okay other than the obvious need to plug the holes in the piston? I can get other shims to change this, and I have a bunch of 17mm .10 and

.15 shims to replace the old ones anyhow.

Should I delete one or both of the 17mm .10 shims after the crossover shim on the compression stack?

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I could help you to tune a given stack, but I cannot analyze a completely unfamiliar fork setup.

maybe someone will chime in...

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About to button these up. Any insight regarding the rebound stack(towards the end of the post) would appreciated.

Right now, on another set of the same forks I closed the holes, and the rebound adjuster seems to have to be all the way out, but it feels okay there.

Would I be off base starting with this stack:

OD (thickness)

17 .10

8 .10

17 .10

16 .10

15 .10

14 .15

13 .15

9 .20

12.5 2.65 Large Clamping Washer.

I think if I take one of the first low speed 17mm shims out, it will allow for better low speed rebound, but still have decent higher speed rebound.

What are tell tale signs of high vs low speed rebound issues? I am a novice at this process.

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