Thursday, September 15, 2016

Super suspension for a Triumph Bonneville by YSS!

Hagon on the test bench at YSS
I love my Bonneville, a love affair which started many years ago when my dad, Mike's Grandad, suggested I should buy a proper bike instead of the Japanese one I had at the time... He claimed, and rightfully so in that era, that Japanese bikes didn't handle. So I bought a 1972 Triumph Bonneville T120... and learned quickly there was a 'slight' difference in build quality between England and Japan at that time. In short it was an absolute disaster! It was without a shadow of a doubt the worst bike I've ever had. It spend more time on the workbench than on the road and cost me more in parts than petrol... A couple of years later I bought a supposedly much better T140, but couldn't find any difference. That too spend more time in the shed than anywhere else. After those two I vowed to never, ever buy a Triumph again! Fast forward the clock to 2009 when I bought my current Triumph Bonneville... after a week or so I said 'I hope it does 100,000 km as I simply loved it. Well, it did... and it did a little bit more than that too. It has literally taken me around the world and has proven itself to be very reliable. Capable of much more than riding to the pub on a Sunday too. My only grief has been with the suspension... A Hinckley Bonneville is a notoriously hard bike to get right, suspension wise. Just read the many forums about it. Everyone is experimenting with all sorts of shock absorbers but no-one gets it really right. Having tried the original Kayaba, followed by Ikon, which failed drastically and then 2 sets of Hagon shocks, I knew I needed professional help to get this sorted. So I asked YSS a very simple question: Can you make the Bonneville suspension as good as what they had done for the Yamaha XT? What followed next was hard to believe...

Little part, big difference. YSS added this PD-valve to the Bonneville front fork which gave it 7-way adjustable compression damping...! The difference is enormous. Less diving under braking and thus more suspension travel while coming down a hill or braking for a corner!
I had expected to get a firm 'no' for an answer. What I was looking for was just too much for a bike designed to have a leisurely ride on. Rear suspension travel is too short for off-road work while the front is basically just a cheap and very crude fork design. The result has been destructive to my back and neck... and yet I love the bike... yeah I know I'm crazy! At the same time I also love to ride in remote areas where the roads are terrible, or better still, totally non-existent. Of course the most obvious choice would be to look for a dual sport or even an Adventure bike... there are plenty on the market but I don't like the aggressive styling of any of them. I'm Old School I guess...

The difference between the Hagon shock (the one on the other side which wasn't broken obviously) and the YSS. The red line is the Hagon, the different colours are just 7 of the more than 70 adjustment options of the YSS
To my utter surprise the answer wasn't 'no' but a firm 'yes'... I asked again to be sure as my hearing isn't what it once was, but the answer was definitely 'yes'...! The next morning my battered Bonneville, covered in mud and showing its hard life, found itself in the centre of the spotlights at the research and development centre of one of the best, if not the best, suspension specialists in the world. In a spotlessly clean R&D centre in Bangkok, it found itself surrounded by 4 specialists, specialised testing equipment and countless computers to analyse the data. It looked so out of place as it went in for major surgery. Surgery which was personally overseen by the head of the R&D department(!)

That's how the left-hand Hagon came from behind the panniers... The pannier rack had been keeping the shock absorber in place and taken the full weight of the bike. The polyurethane bush had worn oval, probably resulting in the fracture of the mounting eye. To be fair to Hagon, they are road shocks, which is rather different than what I've been doing with them. They also outlasted the Ikon's fitted earlier. It's clear though that something much stronger was needed for what I'm doing...
If I ever had any doubts about the need to replace the shock absorbers, then they were all gone just 10 minutes later when the panniers and mufflers had been removed... to show another one of the Hagon shock absorbers had a broken top mounting... only the panniers and rack were holding it in place...! We had two shock absorbers breaking their retainer ring in Georgia, then another one had come undone when it lost its mounting bushes on the way up to YSS and now a third failure saw one snap off completely... I had been very lucky to have made it this far. It also emphasised once more how good the YSS in the Yamaha was when it hadn't even shown any signs of wear while doing the same work (see report here). The Hagon was also found to be quite seriously bend, if that had caused the fracture or the bend was caused by the fracture, we shall never know. Looking at the broken steel made Mike realise just what my back and neck have been through on the many hard sections where he had been just floating over...  

The Bonnie was fitted with 70-way adjustable upside down damping units with custom selected progressive springs... Sounds impressive... and it is! 70-way adjustable(!) Something else which caught my eye, and shows how much they look into every detail at YSS, was the mounting to the bike. Normally you can choose between rubber or polyurethane bushes but YSS doesn't think that's good enough... The YSS mounting point to the bike is taken care of by a proper swivelling bearing, complete with seals etc. This allows the shock to follow any movement of the swingarm totally unhindered, even sideways, without putting any stress on the damper or altering the damping characteristics in any way. The damper travel is also longer than any shock I've had before on my Bonnie and can be internally extended a further 10 mm if needed.

Before fitting they were of course put on a test bench to ensure perfect performance. The data was logged and saved with the Bonnie's own file at YSS. I asked for the undamaged Hagon to be tested as well, just for me to see the difference. It showed the damper was indeed undamaged and worked within specification, but the difference with the new YSS was huge! (see graphs on this page) The rebound damping is adjustable on the YSS, but also the compression damping is quite different to the previously fitted Hagon. Needless to say the ride is now superb... Holes in the road no longer launch me out of my seat, which was a first for me :-) and rather than being thrown back on the road, I'm now cushioned! The improvement is massive... But it also emphasised another problem with the Bonneville... The front end is pretty poor, always has been. The front forks of a Bonneville are strong but very basic. I had even been thinking about fitting forks from another bike. It was one of those things I had planned to look at one day. Now that the rear was so much better, the front felt even worse as the bike was seriously out of balance.

The Bonnie went into the R&D centre again and more surgery followed. Despite not having their own improved fork springs in stock they did miracles again. To begin with they fitted their own 7 way adjustable PD-valve to control the compression damping. They also changed the rebound damping and altered the pre-load. Another problem with the standard Bonneville or Scrambler fork when riding off road is limited suspension travel. The YSS upgrade has also given it 20% more suspension travel over standard (142 mm over 120) In effect my Bonneville front fork now has more suspension travel than Triumph's own Scrambler. 

Meanwhile every detail and every measurement is recorded and put into the computer, both for reference and to show its effects in complex graphs. There were computers around us everywhere and at times it felt like we were in some sort of MotoGP team... with a Bonneville in the middle of it :-) The attention to detail in absolutely everything once again became evident in filling the forks with their own unique oil made for them especially in Europe, oil which is unaffected by temperature variations. They refitted everything, made measurements again and send me away for a first test ride. It was a strange experience, the front suspension had never been this good. Small bumps were absorbed like they weren't there, bigger ones cushioned like never before. It was a weird experience. No more nose diving under braking and thus more suspension travel while on the brakes, while I also had 20% more travel to begin with. Just in front of the factory is a road with damage which had the forks slamming in and out before YSS worked on it, now I hardly felt it... The front is now so much better than it has ever been that I don't need to look for another fork anymore, this one will do nicely :-) especially since YSS showed me how to increase travel even more in the future...!

I almost felt embarrassed to tell them I'd like a little less pre-load, as they had done absolute wonders and it would involve opening the forks again. It felt a bit like whinging about a small detail but at the same time it was so close to being perfect that I felt it would be a shame not to mention it. In the end there was no need to as they already knew! I've said it before, they measure and check everything and had already seen when everything was back on the road again that the rider sag wasn't big enough, knew what needed to be changed and how much, they only waited for my input to confirm... 

If there's one thing I've learned out of this whole episode then it is that suspension is an art. When a good shock absorber has 163 different parts, they all need to be perfect to work together. The weakest link is the decisive factor. That's why everything is measured, tested, recorded and displayed in complex graphs which give the technicians the information they need to set it up perfectly. Top quality components make a top quality suspension, and we have already seen on Mike's Yamaha XT how good YSS is and how well it performed without showing any signs of wear after 40,000 gruelling km (see the report here). But in the end it is always the people behind the product which make it as good as it is. Their enthusiasm and drive to keep looking at every detail to make it better and better is what makes the difference. We had found that drive at the YSS tech centre in Europe and we found it here in Thailand too. Suspension is an art and these guys master it. The result is a Bonneville suspension that is now truly world class. The good news for you is that you can have them too! As every little detail and the setup settings have been recorded, you can get the same set of shocks for your Bonneville or Scrambler. The settings are unique to Nomad-ADV, so contact Nomad-ADV for more info!

The team at YSS who made the impossible, possible! Look at the front fork travel of my Bonneville alone... 


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