I agree. It seems to me if you can use a torque wrench and torque the nuts to the correct setting without stripping or breaking than the studs are not the problem. I've never seen a warped head on any motorcycle and never owned an aluminum head car, so I'm no expert to say the least. What you are saying is the center of the head is warping high, the 2 outer ends low? On the new gaskets I've used in the past, the center section had a kind of sealer like coating on them to make 100% sure it will not leak where yours is. Do these new gaskets have this? If not I'd run some Yamabond #4 or equiv around the area to get a good seal.
baldy110 wrote:
The reason most aluminum heads warp on cars is because they are attached to a cast iron block. The two different metals expand and contract at different rates causing the aluminum head to warp.
The aluminum heads on these bikes are attached to an aluminum case so that problem is not there. It takes a lot of work to warp an aluminum head on a motorcycle.
I would check to make sure the case is not warped. I don't think the case studs are the problem unless they are stripped at the bottom.
I have rebuilt dozens of these engines over the years and never came across a warped heaad or overly streatched studs. The studs will stretch but usually this occurs on highly modified engines with lots of compression.
Are you doing this work or is a shop? If a shop is doing the work, who knows if it's being done correctly and you have to take their word for what is wrong.