chain pitch

[funfisher]

Hi All, I need to replace the chain on my young blokes bike, just wondering how I work out what pitch chain I need.

 

[DHZ_XR8cing]

most mini bikes are 420.
What brand bike do you have?
What engine are you running?

 

[my67xr]

from the DID website,

420, pin length (side to side) 16.75mm, side plate width- 1.8mm
428, pin length (side to side) 18.90mm, side plate width- 2.0mm