Although this is a bit of a general question, because it is on my 2007 WR450 I thought it would still be better to ask it here. I have just put my sub frame back on the bike and looked at the manual to see the torque specifications for the bolts.
It appears the top bolt is 38 NM and the two lower ones are 32NM. I tightened the one on the left fine but the right side by the exhaust just seems to keep going and I get to the point where I am extremely concerned the bolt/hole is going to shear.
I have occasionally come across this issue and I don't know why it happens. The torque wrench isn't that old, it isn't premium brand but I don't think it is way off, also considering the other side tightens fine with it. I wondered if it is the fit of the subrame to the main frame, maybe at a slight angle which means the two faces aren't flat and it flexes as it tightens.
In the end I have now just tightened without a torque wrench as I will probably be removing it again soon anyway to get to the carb. However, what is the general advice going forward on this issue. I would be really upset if I sheared a hole on the frame.