My left side crank seal is leaking into the crank housing would that cause the motor not to run with the air and oil leaking out of the seal? Should i just change both side seals while im at it and will that leak ruin the cylinder head, i just put a new pistion and rings in the thing but the leaking and smoking of the oil has me concerned

 

should be able to change those seals without spliting case depends what u are working on. I have seen where piston blowing apart has also put holes in the lower cases

 

it is a dinli 90cc t rex i just donot want to mess anything up trying to get those seals out

 

You should be able to drill a hole into the face or flat surface of the crank seal. Then put a screw in it and using pliers or vice grips you should be able to pull out the old seal.

Rude Dog