SuzukiSavage.com - Setting Up the S40 Suspension

VortecCPI

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Re: Setting Up the S40 Suspension
Reply #45 - 05/02/19 at 12:54:38

Fork oil was at about 100mm so I lowered it to 120mm. That may not sound like much but on our DR dirt bikes 1/2 ounce can make a big difference when dealing with bottoming. If fork oil is too low forks may bottom. If fork oil is too high forks get too harsh near full stroke.

I spoke to Bruce Triplett and he is looking into a set of Hagon fork springs so I can test them as well...

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Gary_in_NJ

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Re: Setting Up the S40 Suspension
Reply #46 - 05/02/19 at 13:08:11

VortecCPI wrote on 05/02/19 at 04:46:59:
I should also add here Hagon makes a set of fork springs specifically for this bike as part number 400-049-01.

I searched for this part number but didn't find any detail information. Do you happen to know the rate(s), length and diameter of these springs? Are they dual or triple rate? If they are the same or similar to the OEM, they aren't an upgrade.

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VortecCPI

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Re: Setting Up the S40 Suspension
Reply #47 - 05/02/19 at 13:28:43

Gary_in_NJ wrote on 05/02/19 at 13:08:11:

I searched for this part number but didn't find any detail information. Do you happen to know the rate(s), length and diameter of these springs? Are they dual or triple rate? If they are the same or similar to the OEM, they aren't an upgrade.

Bruce is working on this for us now and I will report back what he finds...

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VortecCPI

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Re: Setting Up the S40 Suspension
Reply #48 - 05/02/19 at 13:33:59

PS spring rate is 35/55 lb/in and RT recommends 0.75 kg/mm or 42 lb/in for 150-pound rider so the PS springs seem to be a good compromise.

Bruce said the PS springs will be a bit heavy as you go through the stroke and he is correct. Looking forward to hearing what he can find out about the Hagon set...

Also... Bruce said no problem revalving the damper rods for this bike. He does a lot of HD DR forks as well. The revalved DR forks he did for my CRF230F are nothing short of amazing.

And... Since there are no valves in DR forks when I write "revalved" that means all the DR holes are welded solid and the DRs are completely reworked. You end up with DRs with lots of different holes of different sizes in lots of different locations. It is a position-sensitive system, not a speed-sensitive system but it works exceptionally well. Bruce is a wizard when it comes to DR forks...

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VortecCPI Full Member Offline SuzukiSavage.com Rocks! Posts: 127	Re: Setting Up the S40 Suspension Reply #49 - 05/02/19 at 13:43:09 Out of respect for Bruce's decades of R&D work I will NOT share photos of the DRs in my CR230F but I can share those from other race bikes not done by Bruce...
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VortecCPI Full Member Offline SuzukiSavage.com Rocks! Posts: 127	Re: Setting Up the S40 Suspension Reply #50 - 05/02/19 at 13:43:28 Here is another...
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VortecCPI Full Member Offline SuzukiSavage.com Rocks! Posts: 127	Re: Setting Up the S40 Suspension Reply #51 - 05/02/19 at 13:45:09 Bruce has volumes of customer data and each set of forks and/or each shock gets a serial number so he can trace it back to the customer and his weight, context, etc. Back in the old days ALl Baker's XRs Only used to to the same thing for their custom Honda XR bikes. We had two of them and they were amazing.
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VortecCPI Full Member Offline SuzukiSavage.com Rocks! Posts: 127	Re: Setting Up the S40 Suspension Reply #52 - 05/02/19 at 14:46:46 Just found an old set of 30 lb/in 30 mm x 510 mm fork springs. They are about 10 mm in too long so would have a bit too much preload but they may be worth a try... Perhaps one of each... Impossible to setup suspension that works for both single and two-up rising... All just a compromise...
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Jody72 Junior Member Offline check out Ramz's 4" forward controls on Facebook Posts: 89 Moses Lake, Wa. USA Gender:	Re: Setting Up the S40 Suspension Reply #53 - 05/02/19 at 16:22:47 verslagen1 wrote on 09/15/18 at 23:02:02: I don't think there's any kit, just get the oil seal, dust seal and the keeper. I look through the parts list I did not see anything that says keeper.
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28755 L.A. California Gender:	Re: Setting Up the S40 Suspension Reply #54 - 05/02/19 at 19:43:52 Jody72 wrote on 05/02/19 at 16:22:47: verslagen1 wrote on 09/15/18 at 23:02:02: I don't think there's any kit, just get the oil seal, dust seal and the keeper. I look through the parts list I did not see anything that says keeper. look for a wire that retains the oil seal.
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batman Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 3806 osceola new york Gender:	Re: Setting Up the S40 Suspension Reply #55 - 05/02/19 at 20:45:28 Jody72, Ring, stopper 51156- 40301( -2 required) about $3.54 each
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Jody72 Junior Member Offline check out Ramz's 4" forward controls on Facebook Posts: 89 Moses Lake, Wa. USA Gender:	Re: Setting Up the S40 Suspension Reply #56 - 05/02/19 at 22:36:36 thanks guys!
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Gary_in_NJ

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Re: Setting Up the S40 Suspension
Reply #57 - 05/03/19 at 07:54:20

The "tuned holes" in the damping rod is utter BS. Oil will always seek the path of least resistance. The large hole will have zero damping during slow motions. And the height thing is just laughable. My guess is that this system combines a stiff spring to keep the bike from falling on its face during slow motions, and the larger orifice provides some type of damping at higher speeds. Any orifice smaller than the largest is doing absolutely nothing.

I'm not gonna argue this back and forth. Please start your own thread for this topic because this approach is way off topic.

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batman

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Re: Setting Up the S40 Suspension
Reply #58 - 05/03/19 at 21:49:26

" Oil will always seek the path of least resistance. " Any orifice smaller than the largest is doing absolutely nothing. "
I find that both those statements laughable, all the holes are the paths of less or least resistance , as the fork retracts and the fork oil pressure increases it is transmitted EQUALLY throughout this sealed vessel. the flow of oil will only be limited by the oils height, and the size and number of of the orifices it's allowed to pass through.
Dill two holes in the bottom of a bucket one half the size of the other , pour in a quart of oil and pick it up .both will be under 14.7 psi, but you say the oil will only run out the larger hole, good luck with that!
There's more than one way to skin a cat , I think Vortec CPI may well be on to something ,and I don't believe it's off topic.

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« Last Edit: 05/04/19 at 15:25:00 by batman »

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VortecCPI

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Re: Setting Up the S40 Suspension
Reply #59 - 05/04/19 at 09:00:17

Gary_in_NJ wrote on 05/03/19 at 07:54:20:

The "tuned holes" in the damping rod is utter BS. Oil will always seek the path of least resistance. The large hole will have zero damping during slow motions. And the height thing is just laughable. My guess is that this system combines a stiff spring to keep the bike from falling on its face during slow motions, and the larger orifice provides some type of damping at higher speeds. Any orifice smaller than the largest is doing absolutely nothing.

I'm not gonna argue this back and forth. Please start your own thread for this topic because this approach is way off topic.

Sorry, and with all due respect, you are way off on this one. I have ridden bikes with Bruce's setup and they are outstanding and many riders have ditched RT Emulators in favor of his forks.

As the forks move down the stroke the holes are sequentially covered and damping rate increases. Same when the forks return back to the top. You end up with very plush forks that provide more damping as the stroke increases thus providing amazing brake and bottoming resistance. You have to ride on a set to believe the difference. Rave reviews on ThumperTalk.

They way this works is very obvious if you understand Fluid Dynamics and we do: http://www.eclipseeng.com/services/computational-fluid-dynamics-cfd.html

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« Last Edit: 05/06/19 at 06:34:41 by VortecCPI »

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