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SDI midvalve help (PSF fork)

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I forgot there is a suspension forum so I posted this in the KX450F forum too.

 

Bike is a 2013 KX450F

 

So I decided to get some SDI mid-valves to attempt to keep the fork higher in the stroke and combat the diving. My SDI mid-valves should be here today and I have the forks apart ready to install everything.

 

It's the first time I've had the shim stacks apart and messed with anything like this. I do my own fork oil changes but haven't messed with shim stacks until now.

 

Anyone done this mod yet that can help me out with some pointers?

 

I sort of understand the spec sheet that comes with it, but it looks like the whole compression side is totally different and the spring is not used now?

 

And I just realized I have to drill holes in the piston after looking at the spec sheet.

 

I'm taking good pictures and measurements in case I have to put It back to stock valving.

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We have done this a few times for customers.  The piston can be really good in combination with changing the compression valving and obviously the correct air pressure.  The bleed hole will be different for different riding applications and rider preference.  The main compression valving stock is harsh initially but does blow through the stroke with any kind of force.

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You can call the shop and ask for Justin when you start working on it and have a question.  Its much easier to explain certain things over the phone than typing.  (714) 692 2795 I have the stock valving specs from KYB also if you end up wanting to go back to the stock mid-valve for some reason. 

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You can call the shop and ask for Justin when you start working on it and have a question.  Its much easier to explain certain things over the phone than typing.  (714) 692 2795 I have the stock valving specs from KYB also if you end up wanting to go back to the stock mid-valve for some reason. 

Thanks man, much appreciated. I stopped and went back to stock. I think I would have been alright, but I think I'm missing some shims. The directions say it should include 10x 8id-11od shims, I had two of them. Plus, when I would go to put the piston on the rod, it wouldn't go all the way on, like it wasn't machined to the right spec.

 

I don't know, maybe you have some insight on this.

 

After I took a look at everything, it didn't seem to bad, but like I said, I think I was shorted some shims and the piston issue too.

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That looks ok once you got all the shims and cups etc it should allow the nut at the top to tighten against the rebound shims

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As I posted in the KX450F forum on this, the instructions are not very clear. I got mine together, but remember that I had to put some shims together on the spacer part to add up to what they said was needed. It was confusing and even though I rode with it a while, I ended up sending the forks to Craig Decker at Enzo because I just wasn't certain I had them right. He had some better settings anyway, so I feel better about them now. He said he had installed several SDI valves with success, but he now used the same valve as the 14 CRF450 on the Kawasakis. I liked the fact he didn't try to upsell me the valves he had and said the the SDIs would work fine.

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I'm pretty sure that's not right. There's not enough room for the rebound shims, washer and nut to seat a the way.

Edited by duhameister

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MX317, so when it says included, all those 8id by 11od shims, they're really not included? You stacked your own?

Thanks for the help.

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That's as far as it would go on.

 

IMG_20140610_165920469_zpsf67aa2aa.jpg

 

That is definitely not right, the rebound shims need to fit and the base plate needs to secure around the shoulder of the valving post, also being slightly taller than the shoulder so that the nut does not tighten against the shoulder instead of the plate.  Make sure there is not burr on the ID of the piston that got missed in manufacturing process.  I know some of the small areas need to be hand de-burred after being CNC'd. 

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So one of the managers Chris, just called me from SDI and he said they changed a few parts from the build sheet and he's going to throw a video together for me of the parts and process.

 

Pretty cool, I'm impressed so far. Hopefully I get this together before I ride on Friday.

Edited by duhameister

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I got everything figured out, but the package was missing all the of the 8id 11od .10mm shims, I need x4 to make this thing work. I called some local suspension guys and left some VM's, but if anyone local to Olympia WA can hook me up that would be awesome.

 

Additionally, the pistons did have burrs on the end that I had to file off which were stopping them from going on all the way.

 

Just need those shims now..

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Did you git' 'r dun?

I find it amazing how much 1psi can change the way these forks act. I revalved my MV stiffer (simply added a 24 x 0.15 shim before the existing 24mm x 0.11 shim to stiffen stack AND close up the float, 2014 forks) and with 38psi warm and it's like riding a jackhammer, 39+psi = smooth as butter. Stock balance springs, too, can't find any 3.5N/mm for sale...

Edited by Eddie8v

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Did you git' 'r dun?

I find it amazing how much 1psi can change the way these forks act. I revalved my MV stiffer (simply added a 24 x 0.15 shim before the existing 24mm x 0.11 shim to stiffen stack AND close up the float, 2014 forks) and with 38psi warm and it's like riding a jackhammer, 39+psi = smooth as butter. Stock balance springs, too, can't find any 3.5N/mm for sale...

I got it all done. At 39PSI it's smoother than 38PSI? That's strange. I like what the SDI mid-valve did, keeps everything higher in the stroke and braking bumps are much smoother now. I run 36PSI and 230cc's of oil.

 

I got a deal on some MXT SFF conversion forks and have been trying to those out for the last week. They are like butter, but I think the bottoming is better with the PSF forks.  I'll probably end up selling the SFF forks, I'm having issues getting used to the un-sprung weight again.

Edited by duhameister

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Yeah, softer with more air. Not surprising, just helps at keeping the forks higher in the stroke, out of the stiffer bottom portion of the stroke. Like sometimes more compression damping is better than less.

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I guess that's what the SDI mid-valve helps with. When I was at the track last week I rode my buddies stock 13 KX and it felt like a jackhammer in the front end over rough track compared to the SFF conversion forks. The SDI valve definitely helps a ton. The first thing I noticed was I was able to stand up more coming into turns, the bike just feels more balanced. I might have some SFF conversion forks for sale if anyone is interested.

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