Tenere 700 - Suspension tuning update - Vast improvements!

Riders looking to get more practical performance out of their bike (whether motorcycle or bicycle, for that matter) are wise to first invest in tires and then suspension. Suspension tuning is especially vital to getting the most from your ride. Unless you fit the manufacturer's narrow criteria for rider weight (and many Japanese bikes are under-spring from the factory), chances are your bike will not handle as well as it could--especially on rough terrain.

Accelerated Technologies just north of Peterborough, Ontario, specializes in suspension tuning for all manner of vehicles, but especially sleds, ATVs, and motorbikes. John Sharrard, the brains and owner of the operation, is a former professional racer with championship titles to his name as well as some serious chops as a factory race tech for Honda and Yamaha. He had previously worked magic on my WR250R, completely transforming its off-road and on-road handling. Thus inspired, I was eager to bring him my 2021 Tenere 700 at the end of my first season with the bike, looking for a similar transformation. 

Having read countless online discussions about tuning the Tenere, a clear consensus emerged on the limitations of the factory setup. Mainly: the rear is under-sprung for riders above 165 lbs; putting in a stiffer shock spring requires additional damping beyond what the stock valving will achieve; and there are many complaints with high-speed compression damping front and rear. In addition, many people report that the clickers (fork and shock) have a much narrower range of effectiveness than the total number of potential clicks would suggest--imposing further limits on what damping you can achieve with the stock valving. Unfortunately, you need to modify the suspension if you're heavier than 75kg/165lbs and you plan to push the bike around in the dirt as it was intended to be used. 

For reference, I'm 91kg/200lbs in my birthday suit and 104kg/230lb in my riding suit. The tuning plan was to choose springs based on just me on the bike with no luggage and no preload applied so I'd have maximum range on the preload adjustment for when carrying luggage. That meant changing the shock spring. Interestingly, his sag measurements suggested that the factory fork springs were sufficiently rated--a bit of a surprise to me, given some of the online discussions I'd seen. 

Originally, I had installed an 80N-m shock spring from Rally Raid as well as the Rally Raid preload fork caps. While the stiffer shock spring reduced bottoming, John's opinion was that it still wasn't stiff enough. In fact, he noted that my shock appears to have bottomed even without luggage, so he wondered if that was the source of the harshness I'd felt. (However, I suspect the o-ring was in its lowest position based on other work I'd done.) John also felt the Rally Raid spring was the wrong dimensions for the application, so he replaced it with a longer version rated to 98N-m. As for re-valving, we agreed on a linear strategy to stiffen up the compression damping front and rear. This can be tricky to get right with a progressive linkage in the rear, so we just had to try something and go from there. 

By the time the first re-valving was completed, it was winter (-20C and snow) and unsafe to do a proper test ride. So I had to wait until spring to finally try it. Unfortunately, as soon as I hit the bumpy spring roads, I found the new setup to be extremely harsh. Low-speed compression damping could be managed by the clickers, but high-speed compression damping was so harsh that the bike would catch air off small expansion joints. Dirt roads and stutter bumps were a nightmare to ride at all but the lowest (or unsafely highest) speeds. And hitting any minor pothole or rock was like getting a 2x4 in my backside--leading to a wipeout on one trail that was obviously caused by the wheels pinging off ruts instead of rolling through them. Forget about hitting a pothole while cornering. The bike was simply far too harsh to ride for any length of time except on the smoothest roads or while standing. The high-speed compression damping needed to be dialled way back--but at least we now had some goalposts to work from. 

Below are the shock and fork setup notes from Accelerated Technologies. The details may be a little hard to decipher, so I've tried to decipher them below.

Shock tuning

Factory shock valving (9 valve shims):

• 34 x 0.15
• 32 x 2.0
• 30 x 0.20
• 28 x 0.20
• 26 x 0.20
• 22 x 0.20
• 20 x 0.25
• 20 x 0.25

Shock revalving attempt #1 (done at end of first season; red indicates the changes from factory):

• 24 x 0.10
• 32 x 2.0
• 30 x 0.20
• 28 x 0.20
• 26 x 0.20
• 22 x 0.20
• 20 x 0.20
• 18 x 0.20
• 16 x 0.20
• Washer

As noted, this setup was way too harsh and unrideable. Not recommended! Back to Accelerated Technologies for round #2. This time I rode my bike there and back - 650km in a day, to allow for testing. I brought my camping gear and set up in the back lot while they worked on my bike. Happy company with Bear, the shop dog, who was probably more interested in my lunch. 

Shock revalving attempt #2 (only 8 valve shims):

• 30 x 0.20
• 28 x 0.25
• 26 x 0.25
• 24 x 0.25
• 22 x 0.25
• 20 x 0.25
• 18 x 0.30 (qty 2)

Fork tuning

Factory fork compression valving:

• 16 x 0.10 (qty 5)
• 12 x 0.10 (transition)
• 16 x 0.10
• 14 x 0.10
• 12 x 0.15
• 10 x 0.15
• 16 Washer

Fork compression re-valving attempt #1 (red indicates changes from factory):

• 16 x 0.15
• 16 x 0.10 (qty 5)
• 12 x 0.10 (transition)
• 16 x 0.15
• 15 x 0.10 (qty 4)
• 14 x 0.15
• 12 x 0.15
• 10 x 0.15
• 16 x 0.30 washer (qty 2) to expose more threads for additional shims

Note: the above tuning was too harsh, but not as bad as the shock felt. 

Fork compression re-valving attempt #2:

• 16 x 0.15
• 16 x 0.10 (qty 4)
• 10 x 0.10 (transition)
• 16 x 0.10
• 15 x 0.10 (qty 2)
• 14 x 0.15
• 12 x 0.15
• 10 x 0.15
• 16 x 0.30 washer (qty 2) - Note: not sure if this was added in the revised stack

Factory fork rebound damping:

• 16 x 0.10 (qty 5)
• 10 x 0.10
• 16 x 0.10
• 14 x 0.10
• 12 x 0.10
• 10 x 0.10
• 8 x 0.15

Fork rebound damping attempt #1 (changes in red; this worked well, so we didn't adjust it during second re-valving)

• 16 x 0.15
• 16 x 0.10 (qty 5)
• 10 x 0.10
• 16 x 0.10
• 14 x 0.10
• 12 x 0.10
• 10 x 0.10
• 8 x 0.15

Forks used 100mm of Motul 5 Wt full synthetic fork oil. As John said, if you're not sure what level of oil to choose, go with 100mm because it is almost always perfect, leaving you just enough air as a bumper. 

Setup #2 works very well, as I discovered first through several kilometres of testing with an unladen bike on a forest road near the shop, while stopping frequently to assess maximum suspension travel on the shock and forks. Grip on loose surfaces (especially uphill and downhill) was vastly improved, as was overall handling and braking. (On a historical note, this forest road is known locally as the "Oregon Trail". It's the original road allowance and homesteader trail for what later became County Road 39, located nearby. Gotta love those "lost" roads!)

On the ride home, I gave the fully laden bike (with five clicks of preload) a real workout on a mix of rough pavement and over 100km of rough forest roads. Again, the bike handled brilliantly under all conditions,  and used up the full range of suspension travel without noticeable bottoming, as evidenced by the position of the o-rings on the fork and shock.

It wasn't cheap, but it was well worth the expense to tune the Tenere in this manner. If I was to spend more money on tuning, it would be to upgrade the pistons for better bottoming feel. But realistically, I'm not a hard rider. Most of my riding is in the range of 50-100km/hr on dirt roads, with my sweet spot between 40-80 km/hr so I can enjoy the scenery. While I'm not taking jumps or looking to thrash my bike, I do insist on having the wheels follow the ground when they're supposed to ensure control. For me, the investment has resulted in a great setup and a lot more confidence on mixed surfaces.