Picking up where we left off last time, we sent our long-term 60th Anniversary 2016 Yamaha YZ450F off to Ken Wheeler at Factory Spec to have the suspension setup to suit my weight and riding style. Out of the box for me personally the 2016 YZ450F is sprung a little too stiff and I found I was being beaten up by the bike on our slick, square-edged tracks here in New South Wales.

The aim was to soften the suspension up front and rear, and obviously at the same time ensure the bike would turn, put the power down and stick to the track as well as it possibly could. After a quick chat with Ken we were on the same page with what I was looking for and we left it in his hands to work his magic! Within five days it was all done and ready to pick up; time to take it to the track.

It’s hard to explain how much of a difference the Factory Spec treatment made to our YZ450F – the bike instantly felt completely different. First up, the standard fork springs were changed from a .51 to a .49 spring rate. Next they were valved to hold up in the stroke, yet remain smooth throughout using a custom made mid-valve part designed by Factory Spec to gain better control in the early part of the stroke.

Next up, the rear end. Weighing in between 78-80kg on average, Wheeler felt the stock shock spring should be retained and internal setting changes should be made to gain the best setup for myself and my new fork settings. A slight height adjustment was made internally in the shock along with a custom setting to be more compliant on both corner entry and in acceleration chop. The clickers are set to the same specs as the forks and the high speed is set at 1.5 turns along with a sag the setting of 105mm to finish off rear end updates.

Overall this combination is a massive winner in my book. We did slightly massage the settings going just a touch softer both front and rear at the track, but overall it was basically right on the money. It’s no surprise the bike felt amazing right away, working as current Motul MX Nationals MX2 series leader Nathan Crawford and multi-time MX1 champion Matt Moss’ suspension technician, it’s clear Wheeler knows his stuff.

Another point to mention is that you can have your bike set up exactly the same as ours for just $750.00. I can guarantee there is not one aftermarket part out there that can improve your laptimes this much for such an affordable price. Suspension is the name of the game when it comes to motocross, without a great suspension package all of the motor upgrades and exhaust systems on earth won’t do a single thing. The bike needs to handle correctly or you’re throwing your money away – it’s as simple as that.

Combining the Michelin Starcross 5 tyres, the updated ECU mapping and the updated Factory Spec suspension, our YZ450F really came to life. It went from being a bike that did feel good, but also felt like it could bite you at any moment, to being an absolute dream to ride. Obviously you might buy yours off the showroom floor and love it in stock form, but for me, these updates really made me feel right at home.

Finally we decided to add the GYTR Aluminium Muffler to our 2016 YZ450F to see what kind of gains we would see using just a slip-on system that retains the standard header pipe. Obviously this isn’t exactly what you would expect us to do, but we’ve seen full systems fitted up time and time again, so it was time to try something new for our viewers. The system is designed and produced by FMF in the United States using a range of features developed over their years of championship-winning operation. The muffler has been designed to increase the horsepower and torque throughout the entire power curve and give you a noticeable power increase that is very usable and beneficial, no matter what your riding style or ability is.

The muffler features a space age internal packing designed to five you maximum packing life. This is an important feature for a muffler system as your packing plays a large role in both performance and obviously sound control. The GYTR unit also features an internal core shape that uses high-flow technology to further improve performance. A high-flow modular end cap also includes the removable spark arrestor giving you the option to run with or without with the removal of one simple screw.

Fitment of system was super simple and took just minutes, no tools were thrown, no unsavory language was used, just smooth sailing all the way – a testament to the design and manufacturing of the product. Looks wise, this thing looks awesome, it gives the bike that factory look and it’s a super clean design. We were going for a standard, clean, crisp look with this bike so this system suits it perfectly.

The muffler adds an awesome not to the already throaty YZ450F, it just sounds more distinct out on the track now. I was sure to let a fellow MotoOnline.com.au rider throw a leg over just so I could hear what it sounded like off the bike! Finally the performance, there wasn’t a massive difference on track, but you could feel that added crisp bark throughout the rev range. The YZ450F is already an animal in stock form, so for me personally this was all I was looking for.

We were never looking to go ‘all out’ on this long-term test bike. It was our plan to keep the modifications minimal, yet very purposeful and ensure they were updates that the regular consumer would certainly be searching for. Overall we really put together a great package, the bike turned out amazing and we can’t thank our Yamaha Motor Australia and our supporters enough for getting onboard and helping us fine tune this already awesome 2016 YZ450F.