I recently purchased some 12" wheels for my pit bike as an upgrade from 10". The wheels came with discs and sprocket but the sprocket pitch is 428 but i think the chain size is 420. will this matter as i t seems to go on ok. Somebody please reply ;)
Yes, it will wear them out in a hurry, and that's the best case scenario. A 428 chain has an inner width of 6.35mm while a 428 is a wider 7.95. The sprocket is most likely too thick.