Head gasket--Pull engine??

[Movinfr8]

Just got a 400 EX and it needs a head gasket. I have searched and it seems that it can be done without pulling the motor, just wanted to check. Does everyone use the Haynes manual or how pricey are the factory manuals? and is there a source for them?
P.s. I have no idea if it is bored, will measure when I pull the head. Also the previous owner had removed the chain guard, and promptly therafter the chain broke, resulting in a cracked case. he has it JB welded. any suggestions for a better repair, short of cracking the case and replacing it?
thanks in advance,
Norm

[Movinfr8]

ok, nevermind about the head. I like the way this frame runs outside everything! things were not so easy back in the three wheeled days!

[firefighterjosh]

If it ain't broke or leaking, I wouldn't touch it. Just my .02

[DieselBoy]

if the JB weld is doing it's job, and it's not leaking or showing signs of failing, I would leave it.