I read the August 08 MXA article on the 08 YZ450f "60 inside secrets"... and saw the pictures of the frame cracks, after seeing this...I noticed a 1.5" crack located on the right bottom side of the steering head tube directly on the weld bead on my 07 YZ450. I called Yamaha Customer Support, they told me that cracking is not unusual with an aluminum frame motocross bike and not associated with any weld or quality defect. Further I asked if this issue has been addressed on the 09 YZ's (because I want to buy an 09) - again the answer was "there is no weld issue".
I then asked if they could provide me the type of cast aluminum alloy to ensure I use the correct weld filler material (and heat treat if necessary) when I have the crack repaired- I was told - "this is proprietary, just give your frame to a welder - he will know what to use".
I was a bit distressed at the response.
Just wondering, anyone else has frame cracks in this location? If so, did Yamaha provide any support?