Altitude and over heating?

[Brains]

Hi Guys

Two questions 89' 200
1 - What causes over heating,I've noticed that there is a hissing sound (preasure build up?) coming from the raditors and this is when I'm just kicking it over, not running yet. Is this normal?

2 - The bikes sounds like it is running very rich, it will hardy get going, but the jets are 160 and 48 - factory std. is 158 and 48. I'm at sea level running 40:1 and 97 oct.
With another 200's carb, bike runs great at bottom and then spluters like crazy as you open it up.
Big smoke coming out the pipe!

I,m thinking that this is still a leaking head gasket....I thought I had fixed this fault. Maybey I'm way off the track?

All input appreciated, anything, regardless of the idea as I'm starting to throw my toys out of the cot :debil:

 

[Brian2]

Try running 32:1 this will lean up the carb a bit and provide more lubrication. Test it, and then adjust jetting according to the JustKdx site. http://dirtrider.net/justkdx

 

[Jason2001]

Maybe the hissing that you're hearing is just air leaking past the piston rings and/or reeds. Normal. To check, pull the pipe and carb and listen while someone slowly tunrs over the motor. Of course excessive leakage is bad, but you'll need to judge that yourself.