Project WeeStrom 7.5 - Stromtrooper Forum : Suzuki V-Strom Motorcycle Forums
DL650 and DL650A - 2004 to 2011 DL650 from 2004-2006 (K4-K6) and DL650 or DL650A from 2007-2011 (K7-L1)

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post #1 of 59 Old 04-24-2011, 08:24 AM Thread Starter
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Project WeeStrom 7.5

What Is It?
A 2004 DL650 with 7.5 inches of front and rear suspension travel, and 7.5 inches of ground clearance.







What I Did
I modified the damper rods of my front forks to gain 40mm of front suspension travel, and to increase the ride height. My front ride height increase is actually 27mm over stock, with the proper rider sag dialed in and accounting for the rake of the chassis. Custom springs and spacers were necessary to achieve the proper sag. I also have “widgets” installed in the forks, which basically act like emulators to control damping. These have no influence on ride height or overall suspension travel though.

Stock Fork, Full Compression Travel Measured:


Modified Fork, Full Compression Travel Measured:


Modified Forks Installed:


I also raised the rear of the bike with a custom made longer travel shock from Cogent Dynamics. This shock provides 41mm more travel than stock. The actual rear ride height increase with me in the saddle is 29mm with the suspension sag set correctly, which maintains the bike’s handling balance.



This Cogent shock is a premium unit. The shock uses a stiffer spring to obtain the proper sag numbers for my 225 lb weight. For damping, this shock has a remote reservoir with high and low speed compression adjustments, and adjustable rebound near the lower clevis. Rick made the shock with a 46mm body and a 16mm shaft (stock is 40mm and 14mm, respectively). This allows for a greater volume of fluid, therefore providing performance consistency and more accurate adjustability. The shock body and reservoir are both aluminum, which further aids in heat dissipation (the stock shock is steel, and is an emulsion type, with no piston to separate the fluid from the nitrogen).

Custom Cogent Shock Vs Stock Shock with aftermarket spring


Why I Did This
There are 2 major short comings of the DL650 when it comes to rough road/ offroad capabilities: limited ground clearance and limited suspension travel. I want to be able to ride this bike on basically any non-maintained dirt road and not have to worry about getting high-centered. I also want a plusher ride, but with bottoming resistance.

Stock DL650 High-Centered on a trail ride last year


I know the DL is not a dirtbike and I’m not trying to make it into one. I have a couple other bikes for real trail riding. I’m simply trying to improve it to the capabilities of the other adventure bikes out there, such as the Super Tenere, the GS1200, or the new Tiger 800. I know my modified bike’s offroad capabilities fall short of the benchmarks: the KTM 950/990 Adventure and the F800GS. However, those bikes have some reliability issues and price tags that I’m not willing to deal with, and I probably don’t need that much offroad ability for what I do with my Strom. FWIW, I used to own a 950 Adventure.

If you just ride on pavement most of the time, 5-6 inches of travel is all you really need, as it keeps the center of gravity low and minimizes chassis pitch during acceleration and braking, while absorbing most small bumps. Now start taking that bike on beat up roads and the forks/shock will quickly blow through the stroke and bottom out if you weigh over 160 lbs. If you’ve ever bottomed the suspension, you know it is neither pleasant nor safe. Even if you don’t bottom all the way, the last 20mm of travel are rather “firm”, since there is an oil lock piece in the bottom of the fork tube that quickly increases the resistance to travel. It’s like pulling your parachute in a free fall (it’s better than hitting a wall). I’ve bottomed out the stock suspension (preload maxed out) on just beat-up “maintained” roads and potholes, using all 135mm of compression travel.

So the typical thing to do is install stiffer springs (30% higher rate than stock in my case) and heavier fork oil, and maybe emulators (I did all the above). Now the suspension is less likely to bottom out, which is good. Those same roads that used 135mm of compression travel, now only use 120mm of travel and we are almost out of the dreaded oil lock territory. However, we now have to deal with less compliance (i.e., plushness) over all the smaller impacts. Simply put, the suspension now moves less and the chassis moves more. Not a great compromise for comfort or traction, but better than stock in most people’s opinions (mine included).

With the 40mm increase in travel, I was able to lower the spring rate by 10-20% because there is more travel in the suspension before it will bottom out. Yes, it will still eventually bottom out, but all the impacts up until bottoming cause less chassis movement and better tire contact with the surface, resulting in better comfort and traction. Those same roads that used 135mm of travel with the stock springs and 120mm with the stiffer setup, now use 130mm of travel (the spring rate is 10% stiffer than stock in my case). Another big difference compared to the stock suspension is my bike stays out of the oil lock territory longer, so even the bigger impacts are nicely absorbed by the suspension (no parachute effect).
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post #2 of 59 Old 04-24-2011, 08:25 AM Thread Starter
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Continued...

Why not raise it even higher?

Center of gravity: let’s face it, raising the bike any amount will raise the COG. Consider the Law of Diminishing Returns: a bike that is too top heavy is going to be difficult to handle when the going gets tough, and will offset the benefits of increased ground clearance and suspension travel. About one inch taller than stock is a great compromise, IMO.
Control: Being able to flatfoot a street bike is important to me for safety reasons, such as controlling the bike at a stoplight. It also provides confidence when trying to maneuver a 500lb bike on less than perfect surfaces. I can comfortably flatfoot my Strom with these suspension changes AND my taller seat. I would not recommend these modifications if you have trouble flat-footing your Strom with the stock suspension and seat.


Fork tube overlap:
using a longer damper rod decreases the overlap between the upper (inner) and lower (outer) fork tubes. There comes a point where this will be detrimental to the strength of the forks. With the 40mm longer damper rods, the overlap only decreases about 15% once the additional rider sag is dialed in. This seems reasonable to me. Those who have done the DR/DL fork mods (which uses a damper rod about 40mm longer) have had no complaints about fork strength.

Limits of the rear suspension: you have to raise the rear of the bike by an equal amount to how much you raise the front, in order to retain its handling characteristics. Raising the rear too much will make the chain ride on the front swingarm guide, increasing its wear. Folks who have raised the rear more than 1.5” have reported this problem.
Brake line length: at some point the front end raise will require longer brake lines. This is not an issue with my setup, even with my modest bar risers, but my bike doesn’t have ABS.

Things to be aware of:
The side stand is too short with these modifications and will cause the bike to lean way over (it’s already a bit short with stock suspension). I cut the side stand and welded in a 45mm long section of 5/8” diameter solid rod. The lift from this was about equivalent to using a 1.25” thick object under the stand (the stand is at an angle, so a 45mm increase in stand length is not the same as using a 45mm thick object under the stand). I still wanted the bike a little more upright so I carved out a ¾” thick block of wood and attached it to the stand foot with a couple screws. The nice thing about this setup is I won’t have to cut and reweld the stand if I decide to lower the bike back down to stock height: easily removing the wood block should allow the modified stand to work.

Modified Sidestand


The center stand is too short. You can use a 3/4” thick piece of wood under the center stand feet to get the rear wheel off the ground, or weld in extensions for a permanent solution. Or, remove the stand and sell it like I did. Some skid plates allow you to use them to jack up the bike. This is the easiest way to work on the forks anyways.
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post #3 of 59 Old 04-24-2011, 10:01 AM
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very interesting OhioPT - this seem like the least intrusive way of adding a bit more suspension travel i have seen.

Regarding the front:

did u measure the overlap of front fork stock and after modification?

where or how did u get the longer damper rod?

How much did your longer Cogent shock cost with hi-lo compression and rebound adjust, and remote preload?

And, i see that cogent shock has got a ride height adjuster?

cheers.
AR

L2 Glee;

K8 Wee ABS(SOLD);

SOLD: 06 FZ1; 04 Fireblade; 02 Fireblade; 97 CBR 600
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post #4 of 59 Old 04-24-2011, 03:11 PM
amk
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Great! And probably the way to go. I guess you cut the rod and welded a 40mm tube in?


I have been playing with the idea to throw the oil lock device away for quite a while now. It won’t add any clearance, but will increase the fork travel. And would increase chances for damper rod damage…
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post #5 of 59 Old 04-24-2011, 03:44 PM
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Amazing work! Thanks for sharing this!

B.L.

2007 DL-650 (I gave away in 2012 with 111,000 + miles)
"A word grows to a thought; a thought to an idea; an idea to an act. All the pieces are put together, and the whole is yours."
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"You can talk about doing a thing until everyone finally talks you out of it, or you can actually do the thing"
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post #6 of 59 Old 04-24-2011, 04:50 PM Thread Starter
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Quote:
Originally Posted by amk View Post
Great! And probably the way to go. I guess you cut the rod and welded a 40mm tube in?
Bingo.

1) Cut damper rod (no turning back now, lol)
2) Measure ID/OD with micrometer and source tubing of closest fit
3) Precision machine the spacers to the exact same ID/OD of the damper rods










4) Tig weld the spacers and rods together (I had a pro do the welding). Make sure it's welded straight!



5) Clean up the welds on the lathe and then a belt sander

That's my friend cleaning it up for me. He has a nice shop in his basement.




Finished Product



Last edited by OhioPT; 04-24-2011 at 04:54 PM.
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post #7 of 59 Old 04-24-2011, 05:11 PM Thread Starter
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Quote:
Originally Posted by AceRider View Post
did u measure the overlap of front fork stock and after modification?
Yes. It is around 8 inches, which is quite a bit. So the 40mm reduces overlap by 20%- at the most extended point of the forks. However, little time is spent in full extension. With the additional 10mm of rider sag I used, the decrease in overlap under normal riding is around 15%. I have not noticed any issues with fork strength or rigidity.

Quote:
Originally Posted by AceRider View Post
where or how did u get the longer damper rod?
See my last post.

Quote:
Originally Posted by AceRider View Post
How much did your longer Cogent shock cost with hi-lo compression and rebound adjust, and remote preload?
And, i see that cogent shock has got a ride height adjuster?
My shock does not have hydraulic preload. I can always add one in the future, but for ~$200, it's not really worth it to me since I don't do a lot of 2-up riding. It's pretty easy to get to the preload rings with a spanner. It would be a lot tougher on a DL1000 with its dual exhaust.

That is the rebound adjuster knob, not ride height adjuster. I originally requested the RH adjuster, but Cogent said it would not really fit into the design with the longer shock body and longer shaft length that I needed (the RH clevis adds about 15mm to the overall shock length, compared to the normal clevis). Instead he made the shaft a few millimeters longer, and then put a spacer inside the shock to "lower" it back down to where I initially want it. This way, I can always have the spacer removed if I want the shock a little longer. He can also add a longer spacer if I ever want it lowered (not that I would ever do that )

The cost of the shock was the same as a Wilbers unit with the same features. However, Wilbers uses a steel body (vs aluminum for the Cogent) and a smaller shaft (14 vs 16mm). The larger shaft is able to displace more fluid for the same stroke, and makes the damping easier to adjust. Cogent also has a lifetime warranty, as long as you send the shock in for servicing every couple years (~$80 labor, but replacement seals/parts are free). Wilbers charges about $170 for a servicing, and has a 5 year warranty. Cogent is located on the east coast, whereas the Wilbers dealer is in California, so that makes shipping cheaper and quicker for me. With Cogent, I get to speak directly to the guy designing, fabricating, and assembling my shock. With Wilbers, the shock is made in a factory somewhere in Germany. Plus, Cogent has a cult-like following and reputation among the international dualsport/adventure crowd. All those factors made Cogent the clear choice for me.

I also considered Works Performance (about the same price, but all the way out in California and warranty is not as good), HyperPro (about the same price, but I'm not a fan of progressive springs on a bike with a linkage), and Racetech (cost was hundreds more than the other vendors!).

Last edited by OhioPT; 04-24-2011 at 05:32 PM.
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post #8 of 59 Old 04-25-2011, 01:50 AM
 
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Nice work,
I didn't even know you had a wee. You should cross post this to Caveman riders.

Strom is gone but well remembered. May the Tenere do as well as it did.
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post #9 of 59 Old 04-25-2011, 09:37 AM
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of course that rear shock hasnt got remote preload - problem when u reading things at midnight.

your damper rod modification is very impressive - i would very much like to do something similar to the front - even another 20-30mm travel would be great help with the front.

unfortunately with my lack of skills and necessary tool in that area and my lack of inseam means i probably wont be able to do much. but it's good to know what can be done.

let us know how the bike feels after 1000 miles, once u have a bit more chance to evaluate the pros and cons.

good riding
AR

L2 Glee;

K8 Wee ABS(SOLD);

SOLD: 06 FZ1; 04 Fireblade; 02 Fireblade; 97 CBR 600
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post #10 of 59 Old 04-25-2011, 10:01 AM Thread Starter
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Quote:
Originally Posted by AceRider View Post
of course that rear shock hasnt got remote preload - problem when u reading things at midnight.

your damper rod modification is very impressive - i would very much like to do something similar to the front - even another 20-30mm travel would be great help with the front.

unfortunately with my lack of skills and necessary tool in that area and my lack of inseam means i probably wont be able to do much. but it's good to know what can be done.

let us know how the bike feels after 1000 miles, once u have a bit more chance to evaluate the pros and cons.

good riding
AR
Thanks for the compliments.

Regarding the height, I can still raise the forks 18mm in the triples if I didn't want the height, so that would make the net gain in front end height as minimal as 10mm (compared to a stock bike with the top of the forks flush with the upper triple clamp). That's a pretty marginal difference over stock. Likewise, you could have a rear shock built with the same gain in travel, but with minimal rear height increase. There is a lot of room between the rear fender and tire at full shock compression. You could probably get away with a custom shock with a compressed length that is 10mm less than stock. Of course, that would make the skid plate come closer to the ground under full compression, so you have to be careful. But, you would have more travel nevertheless.

I have a few hundred miles already on the forks. So far, there is no tradeoff IMO with on-road performance. My fork damping is pretty high, so that helps a lot with front end dive under braking/decelleration. If anything, I think I could go down to 5wt fork oil for a little more high-speed compression compliance (I'm using Mobil 1 synthetic trans fluid now, which is about 10w). My fork springs are also stiffer than stock (about a .75 kg/mm straight rate).

I only have a hundred miles on this shock. To be honest, my low-mileage stock shock did a good job once I installed a stiffer spring. It actually has a decent amount of damping. Where I really notice the improvement so far is on really rough roads with deep ruts, bumps, and holes. The new shock is able to absorb the impacts instead of bottoming out. It honestly feels as good as my 950 Adventure did, but it's better on the pavement due to my stiffer forks (the stock 990/950 forks are horribly undersprung from the factory).
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