no only a ktm 50 engine will work good for a 3 stroke 380
How much engine oil do you put in a ktm 85
No. The bolts may line up to actually put the head on, however your horsepower is due to the matching of the piston head with the cylinder head to produce an even flame across the top of the piston. It is important that the radius on the piston matches the radius on the head. The head on the 380 will not match up to the 250 due to the larger piston volume of the 380 vs the 250 or 300.
KTM recommends .5 L of Motorex Top Speed 4T 15W50.
hw much gearbox oil do you put in your ktm 525
KTM recommends Motorex Top Speed 4T 15W5 (0.7L)
Put upgrades on it like fmf pipe and big bore kit
That's something you need to check with a qualified KTM shop about.
ktm dont suck they got all hydraulic clutches and brakes so who put that is dumb. a ktm 85cc will go bout 65-70.
13 ounces
I am assuming you mean gear oil, KTM recommends .7L of Motorex Top Speed 4T 15W50.
.5 L
10w30 will be just fine.