Installation

Continuing the topic of new suspension components, it's time to put the new bits on the bike.  This is where the fun really begins.

First, the front suspension has to be disassembled.  This means the bike goes up on the jack:

The front wheel has to come off and that requires removing the front brake caliper and speedometer drive.  Watch for the speedo cable to come slithering out of its sheathing.  After the front wheel is off, the front fender can come off.  Wrap the brake caliper over the left turn signal to get it out of the way.

With the front end disassembled, the fork tubes can come out.  I did one side at a time to make sure fork alignment stayed the same.  Loosen to hex-head bolts on the upper and lower triple clamps and slide the fork out.  With the fork out, we head to the basement to swap the internals.

The first step is to take the fork cap off and drain the old fluid.  Keep your distance from the fork cap as it is under pressure and will go flying when you loosen it all the way.  Remove the stock spacer, washer and spring.  Drain the old fluid and compress and release the fork a few times to get as much fluid out as you can.  You should be able to fill up a small jar with fluid like this:

According to the instructions provided with the springs, the fluid level has to be 140mm from the top of the fork tube.  140mm is 5.5 inches so grab a ruler and a clamp and measure the fluid.  I used 5w fork oil from Bel-Ray.

With the fork oil at the proper level, we can now install the new spring.  The new spring is significantly longer than the old spring so a new spacer will have to be cut out of the supplied PVC pipe to get the proper level of preload.  Since the spacer decides the amount of preload, its length will have to be calculated.  Progressive Suspension provides a handy chart of spacer lengths for different motorcycles.  The chart shows 2001-2007 Triumph Bonnevilles requiring a 3-inch spacer.  For my 2008, I will have to calculate how long of a spacer I'll need.  For now, I'm going with the 3-inch spacer and if it's too much preload, I'll cut it down at a later date. 

Here is the new spring, the old spring, the new spacer and the old spacer:

There is quite a difference between them.  With the fork back in the vise, place the spring, washer and spacer in the fork tube.  Install the fork cap back onto the fork tube.  You'll have to push down on the spacer to install the fork cap.  The cap is aluminum and the fork tube is steel, so be careful not to muck up the threads as you tighten down on the cap.  Don't tighten the cap yet, wait until the fork is back on the bike before doing that.

Back up in the garage, we can now reinstall the fork tube on the bike.  Slide the tube up through the triple clamps and make sure the top of the tube (not the top of the cap) is even with the top of the upper triple clamp.  Slide the front axle through its hole in the fork bottoms to align it correctly and then tighten the triple clamp bolts.  The procedure is the same for the other side.  When you are done, the bike should look like this:

Now for the rear shocks.  Really, they couldn't be any easier to install.  I chose to change them with the bike off the jack because I'm difficult.  All you have to do is loosen the bolts on the shock, remove the shock and place the new one on the bike.  Tighten the bolts and you're done.  You have to do one side at a time and you will have to lift the bike up a bit as it will sag with only one shock unit on.  Check out how good the Hagon 2810s look:

Awesome.

Now for the test ride.   Initial riding shows the front to be a little stiff.  I may adjust the preload via spacer length or I may spring for Thruxton adjustable preload caps.  Aside from a little stiffness, the front of the bike is amazing.  There's no bounce and no pogo effect; just smooth, progressive dampening.  Turn-in is nice and crisp and requires nothing but a nudge on the bars.

The back of the bike is just as good.  I started with the shocks on the softest setting and it was too soft.  The back felt like a mid-seventies Cadillac - too much float.  Two clicks up from soft and all is well.  The bike feels secure and planted and all of the harshness is gone.

It's amazing how a few simple changes will totally alter a motorcycle's character.  The Bonneville went from jarring and bouncy to smooth and taut.  I'll probably play with the suspension settings a little more as time goes on but right now, it's very, very good.

Mods For the Bonneville

Nowhere in the world of motorcycles does perfection exist.  Even a bike as good off the showroom floor as Triumph's Bonneville has areas that need to be addressed.

One area that is in glaring need of attention is the suspension.  The choice to go with simple off-the-shelf components from Japanese suspension manufacturer Kayaba was great from an economical standpoint.  The simplicity of the suspension helps keeps the costs down and makes the bike more attractive to buyers.  The downside of that is the suspension is cheap.  Bouncy and pogo stick-like are two ways to describe the stock Bonneville suspension.  Awful is another.

A bike like the Ducati Sport 1000 has beautifully machined upside-down front forks and remote-reservoir rear shocks that perform really well.  The Ducati is also a good $4,000 to $5,000 more than the Triumph.

Hope is not lost, however.

The aftermarket for the Triumph Bonneville is quite extensive.  There are literally tons of suspension options from well-known companies like Ohlins, Progressive Suspension, Hagon, Ikon and so forth.  The options are nearly endless.

After almost three years of riding on stock suspension, the time came for me to finally trade my pogo stick suspension for some quality components.  Really, this is an area I've wanted to tackle for a long time.  The Bonneville is a great bike but between the hardwood stock seat and the bouncy suspension, rider comfort leaves a lot to be desired.

Santa has already helped me address rider comfort by bringing me a Thruxton gel seat for Christmas this year.  Now it's time to make the bike comfortable on Pennsylvania's notoriously bad roads and to make it handle Pennsylvania's wonderful curves a little better.

At the front of the bike, the stock fork springs are going to be replaced with a fork spring kit from Progressive Suspension.  The kit for the Bonneville fits a variety of bikes and comes with two new springs, a 10-inch piece of PVC pipe to adjust preload and a nice sticker.

Progressive springs have the advantage of a variable spring rate.  The springs that come stock in the Bonneville's front fork are constant-rate springs.  They have a set amount of resistance and while that can be good when the road is level, finding those glass-smooth roads is tough.  What ends up happening is the front end begins to bounce because the spring is either too stiff or too soft.

With a progressive spring, the spacing between the coils of the spring is varied - the coils are closely-wound at one end and spread farther apart at the other.  The closely-wound coils allow a soft initial spring rate for quick shock absorption with spaced-apart coils allow a stiffer rate for more resisted shock absorbtion.  You get the comfort of a soft spring rate and the resistance of a stiff spring rate in one unit.    

Bringing up the rear of the bike are new shocks from long-time British company Hagon.  Hagon makes a wide range of shocks from replacements for your vintage bike to high-tech replacements for your superbike.  Somewhere in the middle is the Hagon 2810.  They feature a black-painted steel body with chrome-plated steel springs.  They also have a three-position preload adjuster.  The real reason I went with them (other than cost) is the 10-way dampening adjustment.  This way I can dial the back end of the bike to match the front of the bike.

Plus, putting British shocks on a British just seems right.

Once the suspension is dialed in, my Bonneville is going to be a nice little back road burner.  But the components have to be installed first...