Suspension setup build (XR650R focus)

[rhythmofbeing]

I've finally torn the fork on my XR apart and begun the revalve. I have very little suspension tuning experience, and only enough roadracing experience to know what feels good (I'm not able to figure out why yet). However, I'm determined to learn as much as I can. Big thanks to Borynack for all his research.

Here's my writeup so far:

First, here are the terms I've decided to use: a compressive impact is either fast or slow (potholes would be fast, jumps or braking would be slow), and the suspension's setup can either be hard (more resistance) or soft (less resistance). This is pretty intuitive for compression, but for some reason my mind gets confused talking about rebound. In any case, I'll hold to this terminology.

As best I can tell, road racers want soft fast compression ("plush" over small bumps, potholes) and hard slow compression (resistant to brake dive). I don't have a good feel for what an offroad or MX racer would want, but I figure I have to start somewhere.

The three things that you can change in tuning a suspension are 1) the fluid weight 2) the valving 3) the shim stack.

As far as the compression shim stack goes on the XR, the outer diameters (OD) go (starting closest to the valve)
[22 22 20 20 18 16 14 11] mm
The shims 18 and smaller are called the "fast" shims, the others the "slow" shims. Apparently changing the fast shims is not a good idea, but I don't know why. All my shim information deals with shims larger than 18.

To soften the response to "fast" compressions, you drill out the valve to allow more flow. My offroad information recommends going with a lighter fluid (2.5 or 3 wt) to further soften it, but my motard information recommends staying thick (5 wt). I drilled the valves from 1.64mm to 3.64mm (four holes) and got 5wt oil. I think the oil is just a gamble...I'll try it and see how it goes.

As far as shimming goes, the offroad guy has four different stacks he recommends depending on riding style. They go

Super plush: [22 22 21 20 20 ...] : nice and easy, much more plush than stock
Desert rider: [22 22 21 21 20 ...] : handles big rocks and dropoffs, more plush than stock
Desert racer: [22 22 20 21 21 20 ...] : pretty stiff low speed, as plush as stock
MX racer: [22 22 22 20 21 21 20 ...] : for big jumps (I assume not as plush as stock)
My decision: [22 22 22 22 21 20 20 ...] : the 4x22 base setup was recommended for SM (to resist brake dive, I assume. Offroaders don't have near the front brake usage that SM or RR riders have.)

Rebound I don't understand quite as much (there is not as much information about it), but I know that road racers don't want it to be too fast. The difference from compression, though, is that the rebound input force is just a function of how far the suspension is compressed. I drilled the valve to match the compression valve and upped the shims to match the offroad recommendations.

Getting into the more technical side of things, I put the compression stack all together and was picking at it with my fingernail to see how it behaved, trying to imagine the difference between fast/slow compressions. I think the best way to imagine it is using moments for slow compression and normal forces for fast. The slow compression generates a lot of twist in the large shims because it's a steady flow, allowing the fluid to move through the outside of the valve ports at high speed. Conversely, fast compressions are more of an unsteady event. The fluid is pushed through the hole with equal force, so the inside of the stack (where the small "fast" shims have the greatest effect) sees a larger percentage of the overall force.

Those are my thoughts. I wrote them as much for me as for you. Let me know if you have any thoughts or suggestions.

[apa]

I hate to say this but....... your valving & drilling the ports huge may be even softer than the stock set up. You more than doubled the amount of fluid flowing threw the piston. Stock the flow is used to hydrolically lock and slow the travel speed as the holes can only flow so much.

Race Tech uses huge ports on their replacement pistons but compensate with megga heavy valving to slow the increased flow down. They also use a bypass hole in different sizes to soften LSD & LSR.

You can try removing the smallest shim. This will increase the valving amount all the way threw the stack in 2 ways. 1 they can not flex as far open and 2 the increased diameter the other shims flex over.

.

[rhythmofbeing]

Thanks for the input--I'm hoping to learn a lot from you guys who have experience with these things.

The valve bore comes highly recommended for the XRR from desert racers. The stock suspension is extremely harsh on quick impacts. The "super plush" shim setup adds in one 21mm shim and apparently is much softer than stock; this concurs with your comment.

I'm going with 2 extra 22mm shims and 1 extra 21mm shim. I hope that this, along with the valve bore, will allow more flow on quick impacts (potholes, bumps in turns) while still slowing down big, slow movement like braking and jump landings.

So far, though, this is all theoretical. I hope to get it back on the road this week.

Please keep your thoughts coming. Does anyone have a good description of how SM suspension should behave? I'm still trying to figure that out.

[gapp'r buell]

Where did you get your suspension parts from? I am thinking of going to Race Tech as they have the online/DVD/call-in support system in place. And with next to no sumo racing here I would like to learn this stuff for myself.

Good luck with your tuning. I am getting anxious/nervous to start on my DRZ (RM forks) and my XRR this winter.

[apa]

I used to buy shims from Noleen for revalving. Fork shims are tricky to find though and you need to know what size ID, OD & thicknesses you want.

.

[rhythmofbeing]

I went with MX-Tech from recommendations on ThumperTalk. Pricing ends up being about $2.50 per shim when S&H is added in. The service was okay, but not stellar (they left some parts out of the order). I would have gone with RaceTech but they only sell packs of ten.

First major lesson learned in this project: don't depend on JB Weld to hold threads together like welding. The XR forks require a hollow 27mm allen wrench, and standard procedure is to make it from plumbing parts. I don't have a welder, so I figured I could hold the parts together with JB Stik...doesn't work. I'm taking it to a welder tomorrow.

I'm excited to get it together and ride; once I get this tool issue worked out, tuning the stack shouldn't take much more than an hour or two in the future.

[rhythmofbeing]

Well, I finally got everything back together.

Final setup is:

Fluid: 5W

Compression
Ports: 3.64mm
Stack:
(4) 0.1 x 22
(1) 0.1 x 21
(2) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14

Rebound
Ports: 3.64mm
Stack:
(7) 0.1 x 21
(3) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14
(1) 0.1 x 12
(1) 0.1 x 11

These stacks were the result of a lot of research and some constraints on parts available. MXTech didn't send me my entire order the first time, so I just put together what I thought was best based on what I had. I expect to be tuning this often as I get better at it, so I'm okay with starting out less than perfect.

First impressions: I've been riding it on the street the past couple of days. For the most part the ride is uninteresting, so it certainly isn't race conditions. However, brake dive is hugely reduced and the front doesn't feel harsh over small bumps and grinds. So far it's definitely better than stock. We'll see how it goes when I can really get out and romp on it.

Again, feel free to throw out any thoughts or questions you may have.

[gapp'r buell]

What is your weight with your riding gear on?

Thanks for taking the time to post this info, it could not have come at a better time

As well do you have any other pics of your sumo? It looks pretty bitchin' from what I can see in your avatar.

[rhythmofbeing]

I'm about 170 in street clothes, so I'd go 180-190 in gear. I kept the stock springs, as they're set up for about that range.

Here's the bike a few months ago:



It's still about the same now, but I've got the front fender off trying to figure out a better way to mount it. I'm having trouble with the SRC fork guards sliding on it and making a bunch of noise. I also have an Acerbis headlight on there, but there are some HID pods waiting in the wings.

I went out to an abandoned parking lot this morning and rode some steps and dropoffs. The fork feels a lot more plush over curbs and steps (before the rebuild it felt like I was going to pop the tire) and the action on jump landings is nice and controlled. R&D is pretty fun!

[rhythmofbeing]

Update:

I got to ride at about 90% race pace today--first time on the revalve. I was not disappointed. The weight transfer on the brakes was very controllable and the front end never felt upset. I also felt like it was giving really good feedback through the bars. The "track" was very smooth asphalt, so I didn't encounter any braking bumps.

I did occasionally feel a little weave in the front end under braking, but that could be tire pressure, fork flex, or the fact that my rotor isn't quite true. Any suggestions on adjustments to make? I was running about 24psi hot on aging Pilot Powers.

[alexchannell]

This is great info! Thanks a lot for sharing it with us. I have a XRR as well and have been considering what to do with my suspension.

[PowerFiend]

What spring rates are you using?

[rhythmofbeing]

What spring rates are you using?

Stock, which for the forks are .43kg/9.2kg. That's a mix of Borynack/XR's Only 160lb and 180lb setups. Now, that's their recommendation for offroad use; I've heard that SM springs can run stiffer, more like a SX setup.

Alexchannell, I can categorically state that this has been the highest bang for the buck mod I've done to the bike. I think I spent $25 on the shims, $2 on the drill bit, and about $10 on the tool hardware. When you just crank up the compression damping on the stock valving to slow dive on the brakes, the high speed response is enough to jar your teeth out. This setup, while not perfect, controls the dive while still allowing enough high speed flow to not be upset over bumps and edges. It's pretty confidence inspiring.

[onespeedpaul]

subscribed, great thread

[Denn10]

great thread!! FYI i just talked to bruce (aka Borynack) this week on TT and I thought we should do a get together and do some pictorial work on the 650R and L suspension and do both forks and shocks. Do teardown and rebuild and take alot of pics along the way to put in our forums on TT for the BRP. Hopefully we can work something in the near future for others to do their own work, well see as we have our TT get together in SoCal desert in a few weeks.

Thats one frankenbike LOL bet its pretty light too!!

[kan3]

Is there any reason you went with the 5wt vs the 2.5wt fluid? Borynack recommended a nice quality 2.5wt and mentioned it made a noticeable difference over the 5wt with the valving.

I have my order sheet together on rockymountain and mxtech and I might have to change it and try your shim idea instead. Though, I weight about 35-40lbs less than you in full gear so we'll see how that works. How many turns out for comp are you?

[wornknobby3]

Is there any reason you went with the 5wt vs the 2.5wt fluid? Borynack recommended a nice quality 2.5wt and mentioned it made a noticeable difference over the 5wt with the valving.

is there seriously a major difference between the weights, i mean as far as plushness? i would think a jump from 2.5 to say 7 or 10 would be noticeable, i'm also talking the average rider, cuz i'm no pro who feels small increments....

[kan3]

Personally, yes I feel that is something to pay attention to. On cartridge forks you should be able to tell a difference in 2.5wt changes...but that doesn't mean it'll make a difference to you personally. Brand also matters as the cheaper kinds will have a much larger variation between cold and operating temperatures which is noticeable in places that have seasonal riding.

[rhythmofbeing]

Is there any reason you went with the 5wt vs the 2.5wt fluid? How many turns out for comp are you?

Two main reasons for going 5wt: first, I talked with SVMango who did the same setup, and he said he used 3wt and it was still too loose. Second, the local shop only had 5wt when I went in.

I'm 12 out on compression, 16 on rebound. I'm running the stock shock at 6/5 comp/reb. The shock still compresses a bit more quickly than the fork, but if I continue to stiffen it I lose traction on the throttle.

This weekend I rode our race SV for the first time since I redid the XRR forks. The SV has been sorted by a pro suspension guru, and it's pretty much ideal as far as I can tell. The only real difference I noticed is that the SV is still more plush over bumps. I'm going to think about how to get the XRR there, but I think that part of it is that the SV is a lot heavier, so the ride is naturally more smooth.

[kan3]

I also have an sv650 which I take to the track but I can't compare it to the xr since I bought the xr during the winter and it's still crappy out here. Do you know if your still running the damper rods in front or has it been changed out for a cartridge setup?

[Ryanthegreat1]

I also have an sv650 which I take to the track but I can't compare it to the xr since I bought the xr during the winter and it's still crappy out here. Do you know if your still running the damper rods in front or has it been changed out for a cartridge setup?

The XR650R forks are cartridge forks from the factory.

[kan3]

The XR650R forks are cartridge forks from the factory.

I was talking about his sv650 race bike with the pro build

curious if they have $1k+ in the front suspension with ak20/similar carts or the stock damper rods

[rhythmofbeing]

I was talking about his sv650 race bike with the pro build

curious if they have $1k+ in the front suspension with ak20/similar carts or the stock damper rods

No bling, just RaceTech emulators; Penske triple clicker on the back. While the bikes are pretty different, all my race experience is on SV's, so right now that's the standard I judge by.

Always learning...

[rhythmofbeing]

FYI i just talked to bruce (aka Borynack) this week on TT and I thought we should do a get together and do some pictorial work on the 650R and L suspension and do both forks and shocks.

Most excellent! Without his information I wouldn't have attempted this type of modification. While the current pages are none too shabby, more pictures are always good.

Feel free to include any of my information if you can't find anything more SM specific. I modified Bruce's stacks by making an educated guess from the CRF setup sticky in the Honda manufacturer subforum.

[kan3]

Any tweaks to your stack?
I'm placing my order for shims/oil/seals on Monday and wanted to see if you made any improvements. :P

[rhythmofbeing]

Nothing new right now. I think if I were to change anything, I'd like to soften the high speed response. That could be done by changing the small shims (which for some reason I've gotten recommendations against) or perhaps going for 3wt fluid.

[kan3]

I'll order your setup from mxtech and go a higher end oil and see how it works out. Can I ask what brand you were using?

Also, I noticed you listed the rebound as 3.64mm ports but I thought the compression side was the only one to get enlarged?

[rhythmofbeing]

I used Bel-Ray High Performance 5W. Cycle Gear didn't have very many options, and I didn't have very many dollars (still don't, actually).

Ah yes, the rebound porting. Pretty much as soon as I drilled them, I began to wonder if I had done the right thing. I agree that the instructions don't really mention porting the rebound, and I was worried I had screwed it up. However, I have no complaints with the current rebound--I have it set at halfway through the clicker range and it's still more controlled than the (stock) shock. It's possible that would change with a different fluid. If you don't mind taking the forks apart more than once, you should probably leave the rebound ports stock, put everything together, and then decide what you think after some testing.

If I recall, the rebound stack doesn't have a whole lot of thread space for adding shims.

[kan3]

I went ahead and ordered your shim setup and I went with Honda Pro HP 5wt. If that suspension oil chart that is floating around is half way accurate then the Bel Ray 5wt comes in at an average of 6wt/20wt hot/cold where as the honda pro hp comes in at 4wt/15wt hot/cold.

I also ordered the desert rider shim setup for the rear shock as it was leaking when I got the bike and it really needs to be rebuilt. It's suppose to give slightly better rebound control over stock and noticeably better compression...which mine doesn't do anything really.

[rhythmofbeing]

Do you have a gold valve for the shock? I think that's the only way to get the ports the correct size.

One thing we haven't addressed is how the suspension usage affects oil temperature. It seems like offroad forks, with their higher oil volume, would run much cooler during general usage than sportbike forks. I wouldn't be surprised to find a significant difference in performance between street riding and racing just based on the suspension temperature. Your hot/cold numbers mean that we shouldn't be making any tuning decisions based on quick commuting trips. 20wt is downright syrupy!

[kan3]

I was able to get a line on a freshly built works shock with stock spring rate for cheap. I'm going to try that out and see how she works.

I also have the forks off and will be changing the shims to your setup over the next couple of days and hopefully have some test runs by this weekend. When I ordered the shims I ordered all the shims I would need to do any of the setups on Borynack's page or adjustments to your stack. I didn't want to mess with waiting 3-4 days for shims to arrive and missing out on some fun. =]

[rhythmofbeing]

I'm looking forward to hearing about your setup.

[kan3]

Finished the forks and did some riding today but it was 2 hours in the trails so not exactly a good place to gather info. =]

I went with:

Compression
Ports: 3.57mm
Your setup plus the .1 x 16 shim
Stack:
(4) 0.1 x 22
(1) 0.1 x 16
(1) 0.1 x 21
(2) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14
(1) 0.1 x 11

Rebound
Ports: Stock
Desert Racing setup
(5) 0.1 X 21
(1) 0.1 X 20
(1) 0.1 X 13
(2) 0.15 X 21
(1) 0.1 X 20
(1) 0.1 X 18
(1) 0.1 X 16
(1) 0.1 X 14
(1) 0.1 X 12
(1) 0.1 X 11

Stock springs and 110m oil level

Comp damping is definitely much much better. Not exactly right for the trails but it was actually smother over stock in the woops and had very little of the stock brake dive left over. I'm at 10 clicks out right now. The rebound damping seems more controlled and able to react better to woops so I'm hoping it fairs better on the street...but never had much issue with this to begin with. I'm not sure the clicks on this as I constantly adjust rebound damping to the temperature.

I'm switching to street wheels for this upcoming week and am going to do actual comparisons then.

[cm6501]

My XR600R is set with Eibach suspension. You want to set it up for a heavy rider for supermoto. I got mine from xrsonly.com. Now the bike handles great.

[rhythmofbeing]

Finished the forks and did some riding today but it was 2 hours in the trails so not exactly a good place to gather info. =]

I went with:

Compression
Ports: 3.57mm
Your setup plus the .1 x 16 shim
Stack:
(4) 0.1 x 22
(1) 0.1 x 16
(1) 0.1 x 21
(2) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14
(1) 0.1 x 11

Rebound
Ports: Stock
Desert Racing setup
(5) 0.1 X 21
(1) 0.1 X 20
(1) 0.1 X 13
(2) 0.15 X 21
(1) 0.1 X 20
(1) 0.1 X 18
(1) 0.1 X 16
(1) 0.1 X 14
(1) 0.1 X 12
(1) 0.1 X 11

Stock springs and 110m oil level

Did you end up going with 3.5wt oil? I read somewhere that the stock fluid is 7wt, which is really surprising given the tiny ports. I'm interested to hear what you think on road.

Something I still haven't wrapped my head around is how the relief shim (your 16) affects the low speed stack. I intellectually understand that it allows a little more tip flex for the 4x22's before the 21 deflects, but do you know how it affects performance? More feel, slightly less stiffness, etc?

My XR600R is set with Eibach suspension. You want to set it up for a heavy rider for supermoto. I got mine from xrsonly.com. Now the bike handles great.

Did they do a sm-specific setup, or just offroad? Any idea how they changed the shims and ports compared to the 600R stock setup?

[kan3]

Did you end up going with 3.5wt oil? I read somewhere that the stock fluid is 7wt, which is really surprising given the tiny ports. I'm interested to hear what you think on road.

I went ahead and used the 5wt labeled HP pro I bought. Unless you buy some nice shock fluid, most 2.5wt labeled fork fluid is actually around 3.5-4wt hot and 11-14wt cold. The HP pro is actually around 4wt hot and 15wt cold so it's pretty close. You could try the Showa SS2.5 fluid which is suppose to be around 4wt/13wt and I see that at stores a lot.

Something I still haven't wrapped my head around is how the relief shim (your 16) affects the low speed stack. I intellectually understand that it allows a little more tip flex for the 4x22's before the 21 deflects, but do you know how it affects performance? More feel, slightly less stiffness, etc?

I'm in the same boat as you. Generally, I've seen it labeled as a splitter shim on the comp stack if it sticks between larger shims. Personally, all I know is its job is to aid the larger shims in slightly flexing more and doing a better job at absorbing low speed bumps. I would assume this would imply better feel and less harness but truthfully...I doubt most people are skilled enough to know if it were even there. I just happened to order some .1x16 and noticed that PC used one on their racing comp stack which is actually rather similar to yours.

[kan3]

Did they do a sm-specific setup, or just offroad? Any idea how they changed the shims and ports compared to the 600R stock setup?

I think he's just implying you should buy stiffer springs. Personally, if I was only SM'ing my bike..which I'm not...then I'd aim for a 70-75mm sag front and rear. I actually only weight 136lbs so I may be pretty close to that already

I'm just waiting on the other shock to arrive before I try to adjust my sag for 65% sm, 30% trail riding, and 5% RR which is going to be a headache.

[rhythmofbeing]

Personally, if I was only SM'ing my bike..which I'm not...then I'd aim for a 70-75mm sag front and rear.

I was able to get my race sag in that range. It made a huge difference over the stock settings--the bike feels much more perky.

Have you moved your forks in the triples at all? I've seen some bikes with an inch or two of fork tube sticking out of the top triple. To be honest mine already feels like it's falling into the turns; I can't imagine what that extreme of a setting would feel like.

[kan3]

Right now I have 5mm of fork tube above the triple. When I got the bike, the previous owner had them at 15mm above the clamps simply so he could wrap strap around the top of the tubes to mount the front fairing. That was twitchy as all hell on a straight round at anything about 40mph.

[kan3]

Small update:

Wanted to soften the high speed compression on the forks some from the current stack like Rhythm mentioned above. I was playing around with shim restackor app to get some better results...not that I fully understand any of this stuff. =]

My old COMPRESSION stack:

(4) 0.1 x 22
(1) 0.1 x 16
(1) 0.1 x 21
(2) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14
(1) 0.1 x 11

The New COMPRESSION stack:

(4) 0.1 x 22
(1) 0.1 x 21
(2) 0.1 x 20
(1) 0.1 x 18
(1) 0.1 x 16
(1) 0.1 x 14
(1) 0.1 x 12
(1) 0.1 x 11
(1) 0.3 x 10

I tested out this new stack and there is an improvement in plushness over pot holes and other nasty pavement irregularities. Here is a chart showing my original stack at 10 clicks and 14 clicks out, Rhythm's stack at 10 clicks out, and the new stack at 10 clicks out.

You can see that the low speed isn't changed much but it gradually scales to about 4 clicks softer on the really nasty bumps. If you were to change the clamp shim from .3x10 to .25x10 you would get even softer mid to high speed comp...and softer again going to .20x10.

[cm6501]

Awesome post and write up on suspension. But also remember, this is a supermoto bike. Perfect suspension set up is impossible. Road racing and jumping the bike in the same lap doesn't allow proper setup. If you are looking to get your xr650 setup, you might just want to put stiffer springs in the bike and let it go.

[cm6501]

Did they do a sm-specific setup, or just offroad? Any idea how they changed the shims and ports compared to the 600R stock setup?

I used the same shims, and ports, and used auto transmission fluid for fork oil, like all my bikes. I did the the job under 2 hours. I use the bike for sm track use only, with dirt sections. The job is easier than you think.

[alexchannell]

What is the shim ID for the XRR?

Edit found it: 8mm ID