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Discussion Starter · #1 ·
I've seen a few guys do this on here.... 10-25mm.

How low could you go before risking poor high speed stability?
 

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I found a loss of stability in transitions between corners (at the rear tire) at anything more than 20mm. No loss of straight line stability though...

The benefit seems to kinda stop at around 18mm anyway.
 

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Discussion Starter · #3 ·
Thanks for that, Paab!

Actually l found that the slow speed manoeurving of this bike was really sluggish. I have JUST come off a DRZ SM and it was substantially more nimble at speeds below 40km/h. The turning radius as well is huge on the SMC compared to the Suzuki. Only yesterday l noticed that the lock stops are adjustable so l'll be sorting that out today. I've only had one ride on it and still need to adjust the suspension for my weight/riding style. I'm trying to get the front end as light to the touch and razor-sharp as possible.
 

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I found a loss of stability in transitions between corners (at the rear tire) at anything more than 20mm. No loss of straight line stability though...

The benefit seems to kinda stop at around 18mm anyway.
You also have your suspension lowered an inch I believe right? And also re-valved? That might make a huge difference in feel and stability compared to us standard suspension folks. I just raised mine 10mm and it is very noticeable. I have to get used to how "floppy" it feels now. I like the change, but it feels so different when going around slow corners that I think its going to fall into the turn sometimes. Just need to get used to it feeling that way.
 

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Measuring the sag of the smc, we found that it had very stiff springs. We removed some preload and it worked great. IMO lowering the yokes combats the symptom (not enough wait over the front to compress and turn-in), instead of the cause (stiff springs)
 

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Discussion Starter · #6 ·
Measuring the sag of the smc, we found that it had very stiff springs. We removed some preload and it worked great. IMO lowering the yokes combats the symptom (not enough wait over the front to compress and turn-in), instead of the cause (stiff springs)
How did you remove preload?
 

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Its the #6 items. They may vary from bike to bike (because of small differences in spring lengths, one might have more or less than the standard so dont be alarmed)

I think we removed the 5mm ones. You need a mate to help.

- Unscrew the top yoke bolt (otherwise you cant undo the cap)
- undo the fork cap. You may use some paper or thin cloth to avoid marking it
- The bike will drop a bit because it will be only supported by the other spring. I DO NOT recomend supporting it with a MX type center stand cause the sump guard can not support the weight of the bike. I use a bottom yoke front stand which makes life very easy for these kind of things
- Ask your mate to pull the cap up, push the spring down so you can fit a 24mm spaner below the cap (if i remember corectly) to undo the top cap. The nut may be hidden by the spacers, so you might have to push the spring down together with some spacer. TURN THE CAP NOT THE 24
DON'T let the shaft drop in or you will have to "fish it out". Take out the spacer you want and put it back, retighten it, reverse the other steps


Did it about 2 years ago, so I might be forgeting something :rolleyes2:
 

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You also have your suspension lowered an inch I believe right? And also re-valved? That might make a huge difference in feel and stability compared to us standard suspension folks. I just raised mine 10mm and it is very noticeable. I have to get used to how "floppy" it feels now. I like the change, but it feels so different when going around slow corners that I think its going to fall into the turn sometimes. Just need to get used to it feeling that way.
I did this before I modified the bike, as well as after. It had about the same limits in both conditions. Removing preload spacers is good, but the springs will still have too much preload on them. I went to shorter springs. The bike still needs the forks raised because it has a LOT of trail, making it less than nimble. I don't think this bike will ever feel as razor sharp as a real dirtbike, because it has a long wheelbase and a lot of trail.
 

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I just went out to the garage hoping to remove the spacers on top of the fork springs but ran into a snag I hope someone can help me with.

I unscrewed the fork cap and got the 24mm nut loose on the bottom of the cap and started unscrewing it. After maybe 8 full turn the nut refused to turn any farther, like it had hit a hard stop. I am pretty sure I must be missing a step.......help!

Cheers,
Roy
 

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The nut does not need to come off, only the cap. Make sure you loop some safety wire around the nut and through the spring so the rod does not fall back inside.
 

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Thank you exit90a!
 

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Discussion Starter · #13 ·
Raised mine 20mm this morning and it is MUCH better! Closed my lock stops until the forks just lightly graze the radiator guards, made my forks really quite soft and the bike has become a pleasure to rip around on at lower speeds.

Won't be going into the forks.... that's well over my head.
 

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My SMC is a 2008. When I took the fork cap off I found the spacer to be a white Delrin spacer 0.375 INCHES (9.5mm) thick. It came that way from the factory, is it safe to take out that much shim?

Cheers,
Roy
 

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I think you have to hold the 24, and undo the cap, not the other way around :D
 

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My SMC is a 2008. When I took the fork cap off I found the spacer to be a white Delrin spacer 0.375 INCHES (9.5mm) thick. It came that way from the factory, is it safe to take out that much shim?

Cheers,
Roy
There should be more than 1 spacers, some fit under the cap, so you might have to pull down the spring so the spacers drop from under the cap.

If you want to remove 5mm from each fork leg and the spacers are for example 2mm, 3mm, 10mm, take 10mm off from 1 fork leg, and move 2+3 from the other one.

No, i do not believe its unsafe to remove 10mm, worst case is that it dives 10mm more, l believe very small sag is unsafe.

As I said before, there could be differences in the amount of shims as not all spring have the exact same length, so check what you are taking out
 

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Thank you all for the advice, I have only taken the right fork leg apart so far and there was definitely only this delrin piece between the top of the spring and bottom of cap. Which according to the exploded diagram is not even an option.

I had previously dropped the forks in the triple clamp 20mm, so wonder if the additional 10mm from removing the spacer will end up being too much, and adversely effect handling.
 

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So I removed 10mm of spacer from each fork leg last night and took the smc on my favorite test loop this morning. Starts out as highway with terrible cross winds then onto something out of the Isle of Man TT. Every type of turn, elevation change, and pavement imaginable. The front is much improved in all situations. Even in a couple of corners with terrible wash board pavement the front end felt so much less frantic, and more stable. I also did not notice a big difference in front end dive on the brakes.

Thanks to all that gave advise, and to think it costs nothing to do!

Cheers,
Roy
 
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