Suspension improvements are a very interesting mix of science, opinions, wives-tales and black magic. Some people are as passionate about this as politics and religion so......keep in mind this is JUST my opinion.
Warning: This is long and kinda "bloggy" If you want just the basic facts, scroll down till you see this:
Now for the history............
First you'll have to decide how you want the bike to ride. Some people are interested in comfort, others want their long-travel DualSport to handle like a Ducati race bike and are willing to pay the price for this when going off-road (ouch). Some people can ride with long-travel DS suspension and to some it seems like the bike is misbehaving. You have to decide what works for you and what doesn't.
My "OMG moment" happened when I was able to ride Jonah Streets 07 Dakar racer. For those of you that don't remember, this was a modded KTM 525 with suspension done by SuperPlush in San Francisco. The premise here was COMFORT and the ability to finish a 2 week long race that beats the crap out of everything and everyone. Anyways.....the suspension on this bike was a revalation for me. It surprised me because it was so soft but still controlled. It would bottom (gently) landing from about 4 feet of air but it absorbed everything short of that in a very controlled way. My AfricaAlp felt like a stiffly sprung POS after riding this bike.
So, what I've been trying to achieve is a ride that is as close to this as I can get. It will let me go at a reasonable pace off-road and will keep me in control and not beat me up. I AM STILL WORKING ON THIS.
I had the AfriceAlp set up with XR650 fork legs and a 27 mm spacer under the stock AT rear shock. It looked like this:
This isn't a great photo but I'm using it to give you an idea of the relationship between the crank center-line and the axle center-lines and amount of air (ground clearance) under the bashplate.
To be fair to all those using this set-up I had not yet had the forks revalved and was still using the stock XR spring with a larger preload spacer to get the correct front sag/ride height. I rode the bike for about 7000 miles like this. The bike didn't do anything scary. It cornered well on the pavement and went into the rough stuff fairly slowly but with caution. Off-road, I could never get rid of a slightly top heavy feeling and there was a genereal "oh-shit" feeling whenever anything got "interesting". I noticed I was shying away from any kind of steepish/loose climb because the bike was so tall that once it got just a bit away from vertical is was very difficult to dab and correct. (I'm 6'1" and 185, thinish but in good enough shape to hang with the young guys on fires). Riding on gravel or dirt roads I was always kinda tippy-toeing around corners because the bike felt very uncomfortable turning on the throttle and sliding the back end around. There was a feeling of trying to high-side if you entered a corner like a half-miler downshifting and using the rear brake to get the bike a bit sideways. I was just about to spend over $1000 on suspension valving and a new rear shock.
Then, a Suzuki DR750 came up for sale and the suspension money got diverted into another bike. Yeah, it was worth it:
I started riding this beast around and it was so easy. Less suspension travel than the AfricaAlp on paper but, wow, it was much better balanced off-road. I could pivot it around the front wheel on the throttle and it never felt like it wanted to toss me over the high-side. I started riding it more and more and the AfricaAlp less and less (no, not just because the Suzuki was new....well, maybe a little). I spent a lots of evenings in the garage with a beer in hand just looking at the Africa Alp and wondering what should be done. I admitted that the bike LOOKED great (in the "I just rode the Dakar" genre) but didn't WORK like I wanted. A change was needed but I wasn't sure where to go. Is more travel the answer or should I go back to the standard geometry and try to get the best control I could?
In the middle of May, I got a PM here on ADVrider from Don Richardson and a company called Ricor Racing Shocks. http://store.ricorshocks.com/
Don said he was developing a new concept in suspension improvement for older forks that used damper rods. He had read that I had a Transalp and wanted assistance in developing his product for Transalps and Africa Twins. The product is called an "Intiminator" (yeah, I know....but it was developed first for Harley riders so using that name isn't really that surprising and after using the name for a while the "patches and badges" image kinda fades). He offered to let me use the product free of charge if I would give it a fair test and post the test results in the Transalp forum.
I guess this was what I needed to get me motivated to change the AfricaAlp back to a more standard suspension set-up. I accepted Don's offer. He asked that I ship my stock TA forks to him for testing. I did that and while the shipping and building was taking place, I started taking steps to bring the suspension back to stock. So, jack up the bike, replace triple clamps, reconfigure ignition switch, replace front wheel bearings (to accept the smaller TA front axle), remove spacer from rear shock and readjust rear pre-load and sag.
I installed the Intiminators with the stock springs (.5kg/mm), set the preload on the springs and went riding.
I found the bike very much improved. The top-heavy feeling was gone. I could turn the bike with the throttle again and kick the back end out on corner entry on gravel and graded dirt. The front wheel felt so planted it gives much more confidence to sliding the rear around.
With the improvement in front wheel traction. You can use a LOT of front brake on corner entry without the front wheel feeling like it's going to slide. Corner speeds through bumpy corners are much faster with improved control (both on asphalt and off-road). The front wheel ignores those "corrogated" bumps the cars put into gravel roads. I'd actually recommend the Intiminators as a "safety" feature for a stock bike. It will let you brake a lot later into a bumpy corner with no loss of control. If you're leaned way over and the corner gets bumpy the bike doesn't go wide or change lines it just keeps on turning. It's very very nice.
Brake dive was very much reduced so the bike is easier to set up for those squared-off-pivot-around-the-front-wheel corners that are so much fun with a heavy bike on a dirt road.
I thought the valving could be a bit softer and Ricor responded quickly with another set of valves with different shims along with a "tuning" kit that included a tool to disassemble the valve and a package of many different sized valve shims.
The bike now looks like this:
I'm now experimenting with even softer (.43kg/mm) springs and I think I've finally come as close to Jonah's bike as I'm ever going to get with the stock TA forks.
OK....end of blog....and NO, I don't have a mirror in my locker at work.
So, if you just want information on the Intiminators start reading here:
What I'd recommend as a progression through the suspension world is this:
1. Start with stock springs and Ricor's Intiminators for the AT. This is both the easiest mod to make and the least expensive. It involves draining and replacing your fork oil with 5 wt fork oil (real fork oil, please, no ATF or motor oil), removing the stock springs and adjusting the oil level, sliding the Intiminators down on top of the damper rods, putting the springs back in, screwing the fork cap back on and riding. No drilling of damper rods or spring changes. I'd be happy to walk anyone through this step-by-step.
2. If for some reason you don't like this, you can then start with changing springs around and/or playing with the Intiminator shims.
3. If this still doesn't work, you can try the Racetech approach with the Emulators. This will require a racetech spring and drilling your damper rods to allow the emulator to work correctly (which is why I'm not suggesting this first). It's more expensive and makes going back to stock much more difficult.
4. If your still not happy, spend big and go with different high-travel forks. Doing this is NOT for the faint-hearted and involves a lot of time and money if done right. You can follow ATGreg's great lead on this and be right on track. It will involve front wheel mod/replacement, fender mounting problems, making certain that the front wheel doesn't contact the frame or crash-bars on full compression, spring rates, and professional suspension tuning. Then you get to make the same mods to the rear to balance the bike like a longer rear shock. You'll also be coping with extra wear on the swingarm protectors and other long-travel considerations.
In my opinion, The Intiminators are the best mod there is for the stock forks right now. They will allow your damper-rod forks to perform as well as they are capable. They are not a complete substitute for a modern well-tuned (emphasis on well-tuned) cartridge fork, but they are much less expensive and the change is achievable for anyone with basic hand-tools.
The Intiminators work with an "Inertia Valve". There are two seperate damping circuits in the valve. A "hard" setting that is controlled by the shim stack that damps movement coming from the frame...like when you brake hard. The other circuit operates with the moveable Inertia Valve. This valve reacts to fork movement so it's sensitive to bumps. As the fork encounters a bump and moves up, the valve body resists this upward movement (inertia) and opens large bleed holes that gives a much softer damping to the fork movement. In effect what you have is a fork that is stiff when needed and soft when needed. It's a great concept and works very well. Brake dive is controlled with damping and NOT with a stiffer spring. I've actually found that using a softer spring is an improvement from stock. I can get away with this with the Intiminators because of their basic design.
I've had these valves apart many times and have even made a few modifications to one set. I'm no expert but have a bit of experience.
A word about Ricor. Don Richardson is responsible for inventing the "Full Floater" suspension that was purchased by Suzuki years ago. He has spent a lot of time on suspension development for cars, buggies and Dakar vehicles so he knows his stuff. Hi likes and rides motorcycles.....a DR650 so don't hold that against him. This isn't just some wacky new idea from "Ronco". I have links to his stuff at the US patent office for anyone who needs more information.
While Ricor has provided me with a lot of product free-of-charge, I'm not an employee nor do I stand to make any profit or commission on any Intiminators sold to TA or AT riders. I think that the product will speak for itself.
There is (or was) an ADV discount for 50% off on the Intiminators. Call Ricor to ask about how this works before your purchase.
Also, Ricor has developed a new rear shock based on the inertia valve technology. It was first built for the KLR 650 and has been very well received from that community of riders. Don asked that I send him my TA shock for testing and also wants the AT shock in the future. I'm bringing this up since the rear end of my bike is now sorely lacking compared to the front. I'm waiting patiently until I see what Ricor has to offer for the rear. It should be a few months away.
Apologies for lack of brevity.