Help with RMZ450 / Showa A Kit Set Up

Had a mate record some footage from the last outing. Rear end appears to be doing a lot more than the front?

Looked soft in back. Maybe try in 1/2 turn on hsc and see if that helps

RussB wrote:

Looking to get some guidance from the suspension gurus out there... could you confirm or critique my current set up. I'm not convinced its right and I'm looking to improve.

Rider - 180lbs/80KG without kit, 5 9'', 25yo, intermediate level

Bike - 2015 RMZ450

Forks - Showa A Kit 49mm (genuine showa a kit)
0.48 springs
335cc Maxima 5WT Oil
6mm spring preload
51mm rider sag
5mm up in clamps
Comp felt best at full soft, Reb 13 out

Shock - Stock Showa
54N/MM (5.5kg) Spring
102mm Rider sag, 35mm Free Sag, 8mm Shock spring preload
Comp 11 out, Reb 8 out, HS 2 turns out


Forks feel stiff and high in the stroke despite winding out the compression to full soft. Good on the big hits but not supple enough for my liking on the small to mid sized bumps. They feel especially stiff in low speed areas.

Rear feels a little soft and wallowy. I have a 55N/MM (5.6KG) spring at my disposal but this gave free sag numbers of 42mm at 102mm Rider Sag, indicating its on the stiff side?

What do you guys think?

Were they valved for your weight and speed or buy them from someone set up?

CarlinoJoeVideo wrote:

Were they valved for your weight and speed or buy them from someone set up?

Yes sorry, I should have said. Both forks and shock were set up and re-valved for me at SPS Racing here in the UK.

Could well be a valving issue but I would like to try and figure things out a little more myself before sending back for alterations.

Front end didn't move much, even at the beginning of vid when you came into that right hander.

Rear looks soft, front looks stiff.

I'm no suspension tech, but 51mm rider sag seems a little low, maybe should be more like 60 - 70. You could start by taking out that 6mm of preload, hypothetically making your rider sag around 57.

If shock too soft, front will be too stiff. Get the suspension to do its best damping in first six inches of travel, and you will have an optimized setup.

m21 seems to be on the right track: In on the shocks' HS compression 1/4 turn (or more) should help 'weight' the forks for better feel and raise that back-end up for better balance. In on the LS to 9 or 10 may also help hold it up. Start with clicker adjustments before swapping to that stiffer spring (35mm free sag sounds just about perfect).

On the forks, I'd try lowering the fork oil height to 320cc's. You can always add it back easier than having to remove more, hence the 15cc change. You'll know straight away if this if the feel you're looking for. Also, how many rebound clicks total on your forks? Some Kit has quarter-turn adjustment (about 24 clicks total) while others have eighth-turn (40-48 clicks). Out on the rebound will also 'free up' the forks and let them move more; there's a cross-over between comp and rebound that many don't utilize...Keep us updated and congrats on a clean scoot! Video and detailed notes always help, so thanks for being diligent

Thanks for all the help guys.

So can I rightly assume that the 0.48 fork springs aren't the issue? Seems hard to believe the valving is what's holding the forks so high, even at full soft? I do have a set of 0.45 springs for these forks, so may fit 1, to bring the overall spring rate to 0.465. I think both 0.45's would be too soft?

I will definitely try stiffening up the rear to try raise the rear end. I'll try 1/2 turn in on HSC and a little more on LS comp too.

crc245 - Yes you are correct with the rebound, although only on 1 fork. 1 Fork leg (non brake side) features 24 clicks of rebound, the brake side fork 48 clicks of rebound. So I set the one to 13 clicks out and the other to 26. I did try opening out the rebound to 16/32 clicks out with little improvement.
And no problem! I figure the more info I give the better help I should be able to get. Recently bought the 'Race Tech Suspension Bible' and have been really enjoying getting stuck into the workings of suspension. I haven't started on valving yet but can confidently pull apart and rebuild a set of forks, which should make this process a lot easier, quicker and cheaper!

I'm no suspension guru but after watching the video and considering what you have to work with , id install one of the softer fork springs, try 100mm rear sag, open up on the shock rebound. Langhammx has alot of experience with A- kit stuff and I recall him telling me he struggled with his setup until he had both front and rear A- kit components. I cant remember for sure but it seems he had the same setup as you, A kit forks and stock shock. I'd reach out to him, very knowledgeable and helpful guy.

RussB wrote:

Thanks for all the help guys.

So can I rightly assume that the 0.48 fork springs aren't the issue? Seems hard to believe the valving is what's holding the forks so high, even at full soft? I do have a set of 0.45 springs for these forks, so may fit 1, to bring the overall spring rate to 0.465. I think both 0.45's would be too soft?

I will definitely try stiffening up the rear to try raise the rear end. I'll try 1/2 turn in on HSC and a little more on LS comp too.

crc245 - Yes you are correct with the rebound, although only on 1 fork. 1 Fork leg (non brake side) features 24 clicks of rebound, the brake side fork 48 clicks of rebound. So I set the one to 13 clicks out and the other to 26. I did try opening out the rebound to 16/32 clicks out with little improvement.
And no problem! I figure the more info I give the better help I should be able to get. Recently bought the 'Race Tech Suspension Bible' and have been really enjoying getting stuck into the workings of suspension. I haven't started on valving yet but can confidently pull apart and rebuild a set of forks, which should make this process a lot easier, quicker and cheaper!

Good info. I'd try lower fork oil height before swapping one spring for the .465 rate just yet; .48 shouldn't be that far off. Also, don't be afraid to go more on the rebound if 16/32 was a positive change. I have a set on my 08' CRF that require 34-40 out on the rebound for decent action.

Curious why one side is different than the other; Any info on this?


+1 on contacting Langhammx, by the way, as he has tons of Suzuki knowledge...

I went ahead and dropped a 0.45 spring into one of the forks. Once my fork oil turns up I will drop in 335cc's into each and then re measure the sag to see what change the softer spring rate has had. I will try lowering the fork oil if its still too stiff. But the fork oil amount has more effect on the 2nd half of the stroke from what I understand?

crc245 - It appears as though the 48 click rebound adjuster is an A Kit piece and the 24 click adjuster is a stock Showa piece from another fork.
The 48 click adjuster is light gold anodized and has around 10x 2mm bleed holes at the base of the thread for the fork lug. Where as the 24 click adjuster is unanodized and doesn't have the 2mm holes. I imagine at some point the original A Kit reb adjuster got damaged and was replaced with a stock unit.

Interesting stuff on the rebound, I'll definitely try going even further out in future testing in that case!

Will definitely drop Langham a message if I continue to struggle (unless he is lurking here and has some input?) Bought a fair bit of Suzuki stuff from him now, great guy!