Help with smart performace tuning

[chadzu]

I had DaveJ send me out front and rear kits for my '06 yz250. Told him I raced desert style hare scrambles in UT, NV, AZ. He worked me up a kit and sent all the goodies out to me. He suggested middle of the road clicker, and N2 settings, and that is how I have it set up.

The rear is 1000% better in all types of terrain, it totally blows me away what a little shim stack change can do!

The fork has been less cut and dry. I think it is better in the big stuff, and it works really well on the smooth sandy, or smooth whooped out sections. The bottom out performance is good as well and is very progressive.

Its the third race on this set up and I am having trouble with the small rough stuff. Head shake is more noticeable than before and it gets hard to hold on to the bars at points. It seems like every little bump is coming to the bars. It is a little scary now to go for a pass a little off line, or hold it pinned through a rough fast section. When the bumps get bigger the forks work better. I am just looking for a better ride in the small trail junk.

I backed the comp off 2 clicks for this last race and didn't notice much difference. I think the SPI stuff can be made to be really good, I'm just looking for a direction to head in.

Thanks for any help.

[hackman162]

Have ya tried talking to Dave about this?

[grayracer513]

I'm running the full SPI dual-spring Del Taco kit in my '06 YZ450, too. At first, we had a little trouble with this same issue. The bigger the hit, the better the fork feels, and the modified rebound stack on the shock makes you almost want to find the biggest whoops you can to power through. But the little ragged stuff was a bit harsh.

Part of this was my fault from the beginning because I missed the part about restacking the fork rebound altogether, and just left it like it was. Harshness over the little stuff often works out to be a rebound issue. The initial RB response is too aggressive, and the fork doesn't recover quickly enough, which let's the wheel skip from bump to bump instead of following the terrain as it should.

The first thing I did about this was to reduce the base of the rebound stack by a third, from:

20

20

20

13

18

16

14....etc.

To:

20

20

13

18

16

14...

This helped quite a bit, and as the rest of the fork seasoned a little, things got progressively better on their own. Nevertheless, I went back in and got a further improvement by shuffling the stack a little:

20

18

13

20

16

14...

Both these were noticeable improvements, the first more than the second, and I'm currently running the clickers at C13/R9.

The other thing that I did was to lower the oil level. Between the performance of the DSDT fork and the 215.VM2.K5 #5 fluid in the outers, the bottoming/big hit protection is so good that it let me drop the level significantly, which adds to the overall plushness a great deal. 350cc is standard, but I have always run 330 with SPI oil. I dropped this down to 310-315, and it feels even better.

Look into this stuff as it applies to yours.

My son has nearly always hated everything I've ever modified on his bike at first, but when I redid his bike with the full kit like mine, he was stunned by how well it works. He couldn't be happier with it.

On the head shake thing, I run a Scotts damper, so I don't have the problem. My son doesn't run one, and has no complaints. His bike doesn't feel exceptionally skittish to me, though. Oddly, I think the improvements to the shock actually made the front feel more stable. You might try running the rebound a little tighter yet.

Don't be afraid to talk to Dave about it, either. He's just not the sort to leave his customers to sink or swim.

[cj_wai]

I had DaveJ send me out front and rear kits for my '06 yz250. Told him I raced desert style hare scrambles in UT, NV, AZ. He worked me up a kit and sent all the goodies out to me. He suggested middle of the road clicker, and N2 settings, and that is how I have it set up.

The rear is 1000% better in all types of terrain, it totally blows me away what a little shim stack change can do!

The fork has been less cut and dry. I think it is better in the big stuff, and it works really well on the smooth sandy, or smooth whooped out sections. The bottom out performance is good as well and is very progressive.

Its the third race on this set up and I am having trouble with the small rough stuff. Head shake is more noticeable than before and it gets hard to hold on to the bars at points. It seems like every little bump is coming to the bars. It is a little scary now to go for a pass a little off line, or hold it pinned through a rough fast section. When the bumps get bigger the forks work better. I am just looking for a better ride in the small trail junk.

I backed the comp off 2 clicks for this last race and didn't notice much difference. I think the SPI stuff can be made to be really good, I'm just looking for a direction to head in.

Thanks for any help.

i had the exact same problems.ended up with some solutions with dave,s help.post your build sheet so we can have a look.i found the dual del taco needs to be softer for offroading.

[surfer-b]

I would give Dave a call, I also did the SPI dual taco spring kit in the forks and changed the shims. The symptoms you have described were pretty much identicle to what I was experincing when I did my 1st test, I was able to tune out headshake, but I ride mx and not at the speeds that you are I would guess. The small stuff is still more noticeble than what I would like, I believe it can be better, I just havn't had the time to fool with it. It does much better in bottom resistance and the cornering on flat dry slick surfaces is really good.

[chadzu]

Thanks, this is exactly the sort of discussion I was hopping for.

I have not talked to Dave directly about this issue, but he has said that this is a good place to discuss his products. I am hoping to build a consensus with the help of fellow TT'ers and I bet Dave will chime in at some point.

Daves stuff works so good in some areas that I have no doubt that I can find what I'm after.

Thanks for the stack info, I'll check them against what I have and see how far my stacks are off of yours. And thanks for the info on rebound. Maybe I should have gone 2 clicks out on rebound instead. I think I have 330ml in my outers now, so I may pull 10ml out and see how that goes.

[jwaseman]

If you can post your build sheet or have Dave post.

What are your clicker settings?

On my personal bike, I took 2 face shims off the base.

Crossover in the 6th position.

Raised level from 325 to 335 because of the 2 face shims removed.

My base valve looks kind of like this

32

32

32

32

32

18

32

and so on.

Address your mid. mine is setup for moto.

Gray setup looks good.

We need more details. Call Dave he is happy to help!

[chadzu]

Have been running 18 out on comp. 9 out on reb. 330 ml

Ok, here is my stack info.

base mid

32 10

32 12

32 14

32 16

32 13

22 18

32 20

32 piston

32 20

32 18

32 20

32 16

32 11

32 11

32 17

32

30

28

26

24

22

20

18

16

14

11

[DaveJ]

I had DaveJ send me out front and rear kits for my '06 yz250. Told him I raced desert style hare scrambles in UT, NV, AZ. He worked me up a kit and sent all the goodies out to me. He suggested middle of the road clicker, and N2 settings, and that is how I have it set up.

The rear is 1000% better in all types of terrain, it totally blows me away what a little shim stack change can do!

The fork has been less cut and dry. I think it is better in the big stuff, and it works really well on the smooth sandy, or smooth whooped out sections. The bottom out performance is good as well and is very progressive.

Its the third race on this set up and I am having trouble with the small rough stuff. Head shake is more noticeable than before and it gets hard to hold on to the bars at points. It seems like every little bump is coming to the bars. It is a little scary now to go for a pass a little off line, or hold it pinned through a rough fast section. When the bumps get bigger the forks work better. I am just looking for a better ride in the small trail junk.

I backed the comp off 2 clicks for this last race and didn't notice much difference. I think the SPI stuff can be made to be really good, I'm just looking for a direction to head in.

Thanks for any help.

Okay...so clearly something is not right and I doubt it's as simple as the stacks being slightly off.

I mean, the forks should feel more amazing than the rear of the bike, and if the stacks were off, then it would simply feel slightly soft or stiff.

But based on your description here I think there might be something else going on.

With that, let me dig up your build-sheet and get that posted and go over a few other matters.

Till then, I have to ask a few (and seemingly silly) but important questions to ask.

1. When you installed the CLOVER shims did you torque the nut to 60 inch pounds?

2. When you installed the Dell Taco mid-valve section of the kit, are you positive that all the shims in the stack were able to move up and down the 7.3mm collar? I ask because often we get complaints like this where the shims are getting pinched between the piston and collar, given the difficulty of the install.

3. And I hate to ask this but it has come up before. Sometimes users will complain about a set-up being really stiff and we later find out that when they measured and filled the lower chamber of the fork, they got the fork legs mixed up and failed to filled one fork, then doubled-up on the other fork. And obvously 660ml in one fork leg would present a problem.

Let me know and I'll look into your build-sheet here in a bit.

And don't worry, we'll be able to make this perfect. ?

Dave

[DaveJ]

By the way, can you PM me your name and bike type so that I can correctly find your records? I don't think I have your TT user name on file.

Thanks! ?

[jwaseman]

Yes, I'm with Dave on this one. Your stack looks good! There must be something else going on. You should be PLUSH with that stack!

It is very easy to distort the shims while building the mid valve.

Make sure everything slides nice and smooth along the collar.

[cj_wai]

my problem on the dual del taco was the blow off was happening too late.i added some shims to make the 7.3 stem effectively longer.this made the blow off happen sooner and seams to have helped alot. kw

[chadzu]

I think that the install went pretty well. The DDT is a little tricky to get right, but I think that it all fell into place, and was sliding nicely.

I know that I have picked up speed since using these parts, so I know its working good.

I had a bad crash in Saturdays race and earned myself a couple of months off for the bones to set, so I have plenty of time to pull the forks apart. I will give them a good going over and post up some pictures for you guys to look at.

My ultimate goal is to be able to get a ride that is more compliant in the high speed, high frequency sections. It sounds like my stacks are good, and I'll go back and double check the install. So it may just be a matter of chasing the clickers a little.

thanks for all the help guys.

Till then, I have to ask a few (and seemingly silly) but important questions to ask.

1. When you installed the CLOVER shims did you torque the nut to 60 inch pounds?

2. When you installed the Dell Taco mid-valve section of the kit, are you positive that all the shims in the stack were able to move up and down the 7.3mm collar? I ask because often we get complaints like this where the shims are getting pinched between the piston and collar, given the difficulty of the install.

3. And I hate to ask this but it has come up before. Sometimes users will complain about a set-up being really stiff and we later find out that when they measured and filled the lower chamber of the fork, they got the fork legs mixed up and failed to filled one fork, then doubled-up on the other fork. And obvously 660ml in one fork leg would present a problem.

Let me know and I'll look into your build-sheet here in a bit.

And don't worry, we'll be able to make this perfect. ?

Dave

[russ17]

I think that the install went pretty well. The DDT is a little tricky to get right, but I think that it all fell into place, and was sliding nicely.

I know that I have picked up speed since using these parts, so I know its working good.

I had a bad crash in Saturdays race and earned myself a couple of months off for the bones to set, so I have plenty of time to pull the forks apart. I will give them a good going over and post up some pictures for you guys to look at.

My ultimate goal is to be able to get a ride that is more compliant in the high speed, high frequency sections. It sounds like my stacks are good, and I'll go back and double check the install. So it may just be a matter of chasing the clickers a little.

thanks for all the help guys.

Also check the rebound stack. I have seen a few where they pinched the rebound shim on the post threads

[sacfelix]

This is good stough to read because I'm leaning toward a DDT DIY kit for the forks on my 06YZ450f. What did you pay for the kits?

[grayracer513]

my problem on the dual del taco was the blow off was happening too late.i added some shims to make the 7.3 stem effectively longer.this made the blow off happen sooner and seams to have helped alot. kw

That may well have been just what you needed, but for my application (desert racing), I'm not going to meddle with the high speed, deep stroke compression at all. It's too damn good as it is. In that world, the big impacts come really hard, and often unexpectedly. I don't know where all the energy goes, but I still find myself saying, "that should have felt worse", even after all this time. It's really very impressive.

[shockdoc]

I had DaveJ send me out front and rear kits for my '06 yz250. Told him I raced desert style hare scrambles in UT, NV, AZ. He worked me up a kit and sent all the goodies out to me. He suggested middle of the road clicker, and N2 settings, and that is how I have it set up.

The rear is 1000% better in all types of terrain, it totally blows me away what a little shim stack change can do!

The fork has been less cut and dry. I think it is better in the big stuff, and it works really well on the smooth sandy, or smooth whooped out sections. The bottom out performance is good as well and is very progressive.

Its the third race on this set up and I am having trouble with the small rough stuff. Head shake is more noticeable than before and it gets hard to hold on to the bars at points. It seems like every little bump is coming to the bars. It is a little scary now to go for a pass a little off line, or hold it pinned through a rough fast section. When the bumps get bigger the forks work better. I am just looking for a better ride in the small trail junk.

I backed the comp off 2 clicks for this last race and didn't notice much difference. I think the SPI stuff can be made to be really good, I'm just looking for a direction to head in.

Thanks for any help.

Like others said I think you have other issues. Daves got these dialed in pretty good and you should be lovin those forks. What ht are your forks in the clamps? What exactly are your "free" & "rider" sag numbers? Do you know for sure the R/S fork isn't bound up? If you check it like this you won't be assuming its right like if you've just spun your tire & hit the brake or pushed it on the ground:

1.Install both forks and set fork height using calipers or a ruler. It is important that fork height be exactly the same for both sides. Tighten pinch bolts to the proper specs (Top: 18 Ft-Lbs | Lower: 15 Ft-Lbs).

2.Before installing axle make sure the end of it (and the edge of axle hole) has not been "mushroomed" from hitting it with a metal hammer. If theres any lip it must be ground off or fork will bind.

3.Install the axle (use rubber or plastic hammer only) and tighten the axle nut to proper spec (75 Ft-Lbs). If the axle turns while tightening, tighten one right side axle pinch bolt to hold axle in place.

4.Tighten both left side axle pinch bolts to spec (17 Ft-Lbs).

5.With the left side axle pinch bolts and axle nut tightened, loosen the right side axle pinch bolts. Take a small flat head screwdriver and carefully tap it into the slot between the two right side axle pinch bolts. This will enlarge the axle hole. You will then be able to grab the bottom of the right side fork tube and push it in and pull it out freely. You will be able to see the fork settle naturally into position on the axle without binding.

6.Remove the screwdriver and tighten the right side axle pinch bolts to spec (17 Ft-Lbs).

If you're wondering if your forks are currently bound up, put your bike on a stand and start this procedure at Step 4.

Once you figure it out you'll be in heaven:ride:

doc

[DaveJ]

Current build-sheet attached...for the record.

Chad - 06 YZ250.pdf

[DaveJ]

Okay....so...if you have not done so already, I would try running the forks with the compression clickers all the way out.

If this resolves the problem, then it may be worth it to leave the fork as is because when the weather warms and/or when the time comes, you may want that option to bring them back in.

On my YZ, I run the fork compression clickers at about 8 to 12 out on the tracks, and full out when I go off-road. Mine are a bit stiffer than yours but it still works out well.

That said, I've created an alternative build if you want to try something new.

The red are the shims to pull, the green are the ones to add.

Let me know if you need that 8x.25x6 and I'll send some out.

[chadzu]

This is good stough to read because I'm leaning toward a DDT DIY kit for the forks on my 06YZ450f. What did you pay for the kits?

Dave can give better quotes, I needed to buy some other parts as well due to a damaged fork tube so my total ended up being a little more. Dave had amazing prices, and I promise you wont feel like you paid too much!