Vee for victory?
By TMX Archives on 6th Nov 08
Aprilia let our tester Johnno White loose on their new MXV450 Motocrosser he liked it so much, he didn't want to give it back...
HAVING dominated the World Supermoto Championship and excelled in Enduro too, Aprilia's revolutionary off-road department has just accepted a really tough challenge - to take its Vee-twin engine to victory in motocross. So that's what Aprilia has done. It has taken the bull by the horns and built its own race-bred winner and boy have they gone to town with this machine!
When I got an e-mail from Paul Walker from Aprilia UK asking me could if I could go to Italy to test the marque's new MXV450, I was gutted, because I'd rather stay in Atherton - honest.
Well, OK then, I said yes straight away - well as soon as I had checked with the 'old man' to make sure they could cope without me for a few days.
His reply: "Just go - you don't do anything anyway!" Thanks, dad.
So, before I got to ride this new machine, we went to a press conference where we were given the low-down on the new bike. So it comes with a fuel injected motor with a four-speed gearbox, which for motocross isn't the best, in my opinion. I prefer a five-speed box but, saying that, I never felt like I ran out of gears all through the test sessions. Suspension? Well, Marzocchi tailors the front end for Aprilia and Sachs supplies the single shock set-up at the rear. The frame is also a work of art that comprises a tubular steel trellis, which is fitted to forged aluminium side members.
The one thing, or I should say two things, that stick out more than anything else on the bike are the two little pea-shooter type exhausts which look way too small to silence any bike - never mind a 450cc 'crosser. But in reality they are only a cover up as the big exhaust box situated under the seat unit actually dampens most of the noise. I almost forgot to mention that the exhaust system is constructed completely in titanium - factory or what?
The fuel tank tilts up for easy access to the air-box. The creme de la creme is obviously the vee-twin engine which sticks out like a beacon mainly because all of it's competitors come with a single cylinder head and this bike has two.
The vee-twin engine glistens like a new pin and fits inside the frame perfectly although, initially, I did think to myself it did look over complicated for a motocross bike. Having said that, my first bike was a Honda XR75 with an under-slung exhaust when I was seven-years-old and back then I never in my wildest dreams thought that I would ever be testing
a 450cc vee-twin, fuel-injected Italian motocross machine!
The layout of the plastics, seat and tank are really trick and although they scream European - not in a bad way, mind - just, well what I'm trying to say I suppose is that they just look totally different to any other bike on the market right now. The bike is so slim it could almost be like sitting on a 125.
The wheel rims are black, a nice feature, and both front and rear discs come in a factory looking wavy style which are 270mm at the front and 240mm at the rear and they match up with a set of Nissin callipers front and rear.
Another standout item - and a nice touch into the bargain - is the two-tone stepped seat, which helps the rider to hold position at all times.
One thing which I noticed - and again its not a bad thing just unusual for a European bike - is that the clutch was operated by an old-school cable - like most Japanese bikes - and not a hydraulic system.
The Aprilia guys say they don't need a hydraulic clutch because it is light enough, al-though to me, it felt quite heavy, but that's probably down to heavy clutch springs rather than the fact that it was a cable operated system.
So first impressions of the new MXV 450 were pretty good. It looked the part and had all the pedigree for a very strong competitive motocrosser.
So what was it like on the track? Well we were quite lucky as test riders because we were there for two days, which was a real bind - as you can imagine - ha-ha!
So, the first few hours were all about learning how to deal with the vee-twin power delivery. One thing I forgot too mention earlier is that the MXV 450 has two optional performance levels. Setting number one - 'big bang'. Setting number two - 'screamer'.
Now instead of going on here and baffling you with science, I'll try to explain what this means in layman's terms. Basic-ally you buy the bike with two different timing settings to choose from, which are designed to satisfy all riders of all standards.
Reading between the lines and speaking to the chief engineer, all MXVs will come set in 'big bang' mode - unless you specifically ask your dealer otherwise.
Now 'big bang' in my opinion is for the average rider - which is most of us. Now what happens in this setting is that the firing gap between the two cylinders is closed up to produce the excellent performance typical of
a vee-twin while also offering the rider better traction and much more control in slippery conditions.
The other option, which is aimed at the more experienced rider, is what they call the 'screamer' setting. This option allows the bike to rev out a bit more; the firing gap is set to the standard gap for a vee-twin and gives you maximum performance.
Aprilia's chief engineer tells me that if you are quite technically minded you can do this alteration yourself in about two hours in a nice clean workshop. Basically, what you do is take one of the rocker covers off - he recommends the front one because it's easier to get to find top dead centre - and take the cam out and re-position it. The cam has two marks on it, which indicate 'big bang' and 'screamer'.
Once you have completed this, you have to take the generator cover off and re-set the ignition timing so it fires at the correct point in the the cycle. I know it sounds a bit complicated and it probably is for most, but the fact that you can do it if you want is mega.
Not only do you have this option but which ever one you decide to use you also have a programmable ECU (electronic control unit) which lets you switch between two different engine maps at the flick of a switch on the handlebars. You have a full map which is better for good grip and dry conditions and a soft setting which is best for slicker surfaces.
Anyway back to what I thought of the bike when riding it. Because of its looks and 'trickability', I had to give it ten out of ten. I wasn't overly keen on the kick-start position. It felt a little bit far back and had a tendency to stick down if you kicked it too hard, but once the engine was running I began to get into it.
The last bike I rode was the Kawasaki KXF at the very same track in Italy three weeks earlier, so that was good for comparison purposes and, at first, I wasn't that impressed.
Initially, I felt the MXV was a bit cumbersome and heavy, but once I relaxed and started to let the engine pull, it became easier and easier to ride. I could tell the difference between 'big bang' and 'screamer' options and I settled for 'screamer', but with the soft setting on the ECU. I found this suited my style perfectly, more traction from the bottom but it also enabled me to rev out the motor more if I wanted to.
The four-speed box was fine and sometimes caught me out because I thought I was in third but actually in fourth, which shows how much grunt this bike has. It really liked to be kept in the top two gears and just pull - it was very strong.
I loved the way it turned, although I felt the rear end was under damped and a little bit soft. I hated the rear brake position, it was too high and for the first two sessions I felt like the
bike was under-powered. I then realised that because of the position of the rear-brake pedal, I had been riding with the rear brake dragging. Once I got the pedal position adjusted, I was happy.
The more laps I did, the more comfortable I became on this bike and towards the end I didn't really want to get off.
It cornered and pulled well. The seating position with the stepped profile worked well too. All in all a pretty impressive bike.
I'm not sure if Aprilia has announced a recommended retail price yet, but I think you will be looking around the £6,000 mark which isn't that bad when you think of the technology that has gone into building this bike!
SPECIFICATIONS
2009 Model Aprilia MXV450
ENGINE:
Type: Liquid cooled, 77° vee-twin four-stroke with 4-valve single overhead cam, rocker operated exhaust valves, chain timing drive, titanium valves
Bore x stroke: 76 x 49.5 mm
Displacement: 449 cc
Compression: 13:1
Fuel system: Integrated engine management system controlling ignition and fuel injection. Hard and soft ignition mappings selectable from handlebar switch.
Throttle body: 38 mm.
Fuel: Lead-free petrol
Ignition: Electronic digital (batteryless)
Starting: Kick-start.
Lubrication: Dry sump with separate gearbox lubrication
Gearbox: 4-speed
Clutch: Cable operated multi-plate unit in oil bath
Final drive: Chain
Exhaust: Manufactured in titanium. (Conforms to 2009 FIM standards)
CHASSIS
Frame: Cr-Mo steel perimeter frame with aluminium alloy vertical members and lightweight rear frame section
SUSPENSION
Front: 50 mm Marzocchi upside down fork with adjustments for compression and rebound
Rear: Pro-Link with Sachs monoshock, adjustable in compression and rebound
BRAKES
Front: 270 mm lightweight stainless steel floating disc with Nissin floating caliper
Rear: 240 mm lightweight stainless steel disc with Nissin floating caliper
WHEELS
Front: 1.60 x 21" black anodised aluminium alloy
Rear: 2.15 x 19" black anodised aluminium alloy
TYRES
Front: Dunlop 80/100-21 51M
Rear: Dunlop 110/90-19 62M
DIMENSIONS
Overall length: 2,190 mm
Overall width: 815 mm
Ground clearance: 1,285 mm
Seat height: 960 mm
Wheelbase: 1,499 mm
Fuel Capacity: 7.4 litres
Specification: