discolored crank

[kyle24]

I cracked the skirt on my piston a while back and when i took the jug of and spun the crank i saw that on the one of the wheels there was a blue and purple mark like it got really hot i would imagine that it is from the factory liek that but if anyone would like to put in some input i would appreciate it

 

[Awk08]

pics !!!!!!!
but yeah there is some discoloration from the factory

 

[kyle24]

thats what i was thinkin cause i couldnt see thoughs little pieces doing that and its not a very big spot i assume its just from heat treating or something but figured i would ask

 

[hudack]

what caused the pistion to shatter ????

 

[YFS101]

its completely normal.

The discoloration is from the crank being heated while installing the crank pin.
Also some shops like to weld the crank pin. Ive welded race cranks for blasters, banshees and pocketbike engines. this usually discolors the crank as well.

Its bad if the rod is blue at the bearings

 

[kyle24]

ya it just a spot about the size of a quarter give or take so i wasnt really worried about it but i thought i would ask thanks for your help