Overheating on high load and revs only, what could it be ?

[poelinca]

Changed the reeds, PV rocker arm and the air filter, went out for a ride and it looks like the bike is overheating only on high load and high revs.

I tried riding with low revs and it doesn't seam to overheat, nor does it overheat with high revs on flat ground, strictly only when pinning it on hill climbs (takes about 5-15 minutes to overheat, depending on the climb). The engine pulls really strong in all conditions, especially on high revs.

Strange thing is that the bike didn't smoked at all, so i had to top off with some oil to get a little bit of smoke out the pipe. Engine ran good but it didn't last too long, soon enough i had to put more oil as the pipe wasn't smoking again and had that lean kind of sound. Ended up using double the amount of oil that i usually premix.

Jetting is JD red needle #4, 180 main and 40 pilot (should be on the rich side, never had problems with this setup under the same weather conditions and trail).

I highly doubt it's only bad gas/oil.

Maybe sucking air witch leans out the already rich mixture ? If it does suck air thru somewhere, doesn't that mean it should also affect low revs ?

Maybe radiators have tiny small pores ? Last time when the engine overheated it was fixed by welding the tiny pores on the radiators, but then again it used to over heat on low revs too back then.

Maybe piston rings ? I think i have roughly 35-40 hours on the top end.

Maybe crank seals ?

Thanks