6 months ago

Dirt and Trail Magazine 2021

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  • Bikes
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YAMAHA YFZ450 R Gareth

YAMAHA YFZ450 R Gareth Rawson Railing the burms HOWEVER. Given the fact that quads on the whole do not sell anything nearly like what they used to, importers are quite selective so the models that do arrive quickly seem to find homes – or, thanks to increased costs, the importers are reluctant to turn them into Demo units. We have noticed a bit of a resurgence in the quad market lately. After lockdown it’s as if people have dusted off their old machines to hit the trails again. Most companies have stopped sports quads just about all together, focusing rather on their utility lineup. Yamaha has continued to manufacture and update both the YFZ 450 and the 700 Raptor every year. When we visited Linex Yamaha a few months back, we saw this spankin new YFZ on the floor and we submitted a written request to ride it. After much debate between head office and the dealership, they agreed to give us a shot. Back in the day, our Kyle Lawrenson was actually – wait for it – a qualified Yamaha instructor. He met up with Linex Yamaha’s Gareth Rawson at ERORA on the East Rand and they spent a few happy hours tearing up the track. “It’s been a long time – but it’s like riding a bicycle – you never forget” says Kyle and pretty soon the guys were hitting the big jumps and railing this beasty through the berms. It is awesome fun. No matter what your two wheeled buddy tells you… About the Quad: Powertrain: The engine is basically a fire snorting 449cc, fuel-injected four-stroke just like you find in their dirtbike lineup. The liquid cooled dual overhead cam power plant has Yamaha’s five-valve head with titanium valves. All of the power generated by this sophisticated engine is fed through a five-speed manual transmission. Yamaha incorporates a wet multi-plate assist-and-slipper clutch in the drivetrain. Four-stroke engines have strong engine deceleration (Decompression braking) which, with the use of the rear brake is helpful for slowing things down. In a racing scenario around an MX track like this, it can cause the rear suspension to bind and buck over braking bumps. A slipper clutch prevents rear wheel chatter and over-rev when you downshift and hard engine braking happens. To put it simply, it acts more like a two-stroke engine. During hard throttle chops, the machine feels as though it freewheels, due to low compression, but in actuality, the clutch is slipping to ease engine deceleration to the rear wheels. Another benefit of Yamaha’s assist and slipper clutch setup is a light, soft clutch feel. Ramps built into the clutch pressure plate increase pressure on the clutch pack as rpm increases. Thanks to this mechanical advantage on the clutch pack, Yamaha was able to employ much softer springs in the clutch. That requires less effort at the lever making it easier to feather the clutch lever to put down as much power as you need, translating into more control over the machine. Ergonomics: The riding position of the 450R is familiar, low and sporty feeling. It is great for shorter riders, but tall oafs like ours fit just fine.