NSR250 Spark Plugs.
For the MC16 model, use NGK B9ECS or B9ES spark plugs. Recommended alternative: ND W27ES-C
For MC18 onwards, use NGK BR9ECM. Recommended alternative: ND W27EMR-C
BR9ECM
B9ECS Plug gap for all types should be 0.7-0.8mm
B9ECS Plug gap for all types should be 0.7-0.8mm
When using the HRC head conversion on MC21 and MC28 models, use the HRC RS250R "shorty" spark plug part# 31930-ND5-003 (No. 10 plug NGK# R5300A-10) or part# 31940-ND5-003 (No. 10.5 plug) and special HRC RS250R cap part# 30700-ND5-751.
Before fitting new spark plug cap, trim 5mm from the end of the HT lead.
Plug gap 0.7mm