There’s been a lot of discussion on spark plugs lately on the forum, NGK has changed their numbering system to show the four digit stock order number and the regular number. Most stores go by the stock number. Here is a list of the most popular plugs for two strokes.
B4HS : 4110 / B5HS : 4210 / B6HS : 7534
B7HS : 5110 / B8HS : 5510
Extended tip
BP4HS : 3611 / BP5HS : 4111 / BP6HS : 7331
BP7HS : 5111 / BP8HS : 2630
B4HS : 4110 / B5HS : 4210 / B6HS : 7534
B7HS : 5110 / B8HS : 5510
Extended tip
BP4HS : 3611 / BP5HS : 4111 / BP6HS : 7331
BP7HS : 5111 / BP8HS : 2630