From MOTO Issue 94 – August 2013
Words by Tom Radburn. Photography by Adam Duckworth.
Total Riding Hours: 12
Tracks: Kiwi’s compound, Westonbirt, Booker’s compound, Cheddar MX
Mods so far: Suspension set-up, ODi CFT bars & grips, Samco Hoses, Evans coolant, ProX clutch plates, Yoshimura RS-4 exhaust, Acerbis plastics, GP Grafix, RFX levers
Finally summer is here and I’ve ridden the MOTO YZF450 in proper hard-pack conditions for the fist time, which has shown both positive and negative sides to the bike.
I’ve been riding at Cheddar Moto Park this month, which is a cracking track in the South West that offers just about every obstacle riders need to hone their skills in one lap. First sessions started out heavy going as the track was drenched to combat the nice hot weather, but these are conditions the strong YZF450 motor absolutely loves. Give the bike something to dig its tyres into to get drive and it ploughs through even the worst mud so easily, especially as the Yoshimura pipe has given the bike and even smoother and longer power curve.
As the days went on and the track began to bake and polish up into real hard-pack conditions the smoother and longer power delivery the Yoshi RS-4 has given the bike with its most restrictive baffle fitted the terrain perfectly. The strength is there to pull third out of even very tight turns and this makes for great traction and drive, perfect for blue groove.
However the front-end stability wasn’t so great. I hadn’t altered the bike set up from previous outings in grippier conditions and as the track dried out the YZF’s front wheel was becoming increasingly nervous and wanting to push out. Unless there was a rut to turn against it was a handful. Pushing the forks up 4mm in the clamps to shorten the wheelbase a little made a small improvement but I also felt the front fork was sitting too high in the stroke on sweepings and not weighting the front wheel enough to grip. So to combat this I went two clicks softer on the compression and one on the pre-load so that fork sat down a bit further in the stroke. Together with pushing the fork up in the clamp I finally got some weight on the front wheel and was able to turn with more confidence.
This goes to highlight again that the YZF is more than just a fuel and ride bike. You do need to think about track conditions other variables and make adjustments to suit in order to get the best performance from the bike every time you ride.
Also a cause for concern were the tyres. The bike came from Yamaha with a weird combination of Michelin XC-spec tyres for some reason and I’ve been running these to date simply because I didn’t want to waste nearly new rubber. However they suck for motocross, especially on hard-pack and especially the front tyre which simply rolled the knobs at speed and lacked grip. After a day at Cheddar they are trashed so now I’ll be fitting some proper MX-specific rubber although most likely I’ll be sticking with Michelin as I like their MX range.