"I mostly ride in deep sandy tracks with lots of traction and braking bumps that can bottom out forks. I also ride in very tight trails again with soft dirt. Occasionally I come across some hard packed clay, but if it's been raining that clay becomes muck. I want to know if the new 450 is better than the YZ250 in any of these conditions." - bhorrigan
As for bottoming out the forks, that is a lot about the rider and the speed you are riding. We don't find that the Yamaha bottoms any more than any of the other 450s but what we do know is that when it bottoms, often just adding a little more oil to the forks can have a really positive effect on this. If the fork is working good everywhere and it is only bottoming, adding 5cc of oil at a time to each leg should help it out.
We do not test motocross bikes in the trails. Why? Because it is not what they were designed for. We know riders use them for this but for us to tell you how something works for something it wasn't designed to do just does not make sense on out part. Especially when Yamaha makes WRs for the trails. Generally the two-strokes motocross bikes are better on the trails than the four strokes, if you are asking my personal opinion.
"Basically, a run down on how the new swingarm helps improve the bikes turning ability, and suspension action, if it does...
It would also be nice to hear some about the bikes power. It seems like the first thing guys do when they bought the 08 was to go out and put on a aftermarket exhaust. However, it seemed like the stock system provided plenty of power that came on so" - pin_it
We could not really pinpoint the changes the swingarm made. Since our 2008 bike had a pipe and different tires, that is enough to change the feel of the bikes enough so that even high level test riders might not be able to feel the difference. From talking to Yamaha test riders (who tell it straight) there is a slight benefit in traction that you can fell in going back-to-back. We felt nothing bad from the new swingarm, that is for sure.
"The first thing I want to know about this bike (and any new bike for that matter) is how it held up. We don't get to rebuild a motor every week, so durability is a big concern. Yamaha is tops in this dept, and I for one would like to know if they are keeping it that way.
Does it flame out? How's the jetting and handling? How fast did it run through a tank of fuel, did the valves come out of spec at any point while you were testing..." - skipkh
We have over 10 hard running hours on our bike already and it is still getting faster and easier to start every hour. We have done one oil and filter change. Our experience with Yamaha 450Fs is that that peak at about 20 hours and run really strong easily till 30 hours (all approximate) and beyond. We'd suggest looking at the top end at 40 hours and then decide on how you are wearing stuff out and determine a maintenance schedule for your bike. You should check the valves more frequently. And if they are not moving, don't worry about them. Live by the hour meter. We have not checked our valves yet, maybe at 20 hours but I wouldn't suspect to see anything out of spec.
The bike does not flame out, the jetting is about perfect for us running Texaco 91 octane pump gas at elevations from 0-3000'. For the handling, see the test. As for the fuel range, we can ride a solid 45-minute GP and push an hour-long moto on a tank of gas.