July 19th, 2011, 07:27 PM
Joined: Jan 2011
From: Oxford, MI USA
Piston 70deg head bolts stuck top end
After having the y fitting in radiator hoses fail on my 2010 FX450 at race a couple of weeks back and seriously overheating the motor. I had some concerns about the piston, then during an enduro last weekend it started blowing coolant out the overflow. So I decided to tear it down and replace the piston and head gasket. First the piston is the same as the 450 xcw KTM so there are lots of options for a piston. I am going to give the PRO X a try, probably would have went with a Vertex or Wiseco if more time had permitted. Anyways as far as tearing down the topend it is pretty straight forward, except the head bolts. I managed to break 3 of them free and really had a tough time with the last one. Thanks to Jeff Slavens for his video on how to losen the head bolts on the KTM, since this top end is the same it suffers the same problems with the frozen bolts. The thing on the berg to get a decent swing at the drift to losen the bolt, you need to remove the wheel, forks and fender to get a swing. I would also recommend removing the water temperature sensor before getting too gonzo. During disassmbly I was assessing the wear on valve train and piston, amazing everything looked great 60+ hours of hard use. That Shell Rotella T sure seems to protect everything even under the most severe conditons. And for the price you can change everytime you ride if you want. All the parts will be here tomorrow, so I will update with anything else I find. Reassembly looks pretty straight forward.