SPARK PLUGS: NGK 4111 BP5HS
Posted: Sat Feb 01, 2025 4:23 pm
G'day, my 138 has at present NGK 4111 BP5HS spark plugs. Are these so long that they'd be hitting on the valves? Should I be worried? Thanks for any info.
The geometry inside a grey depends a lot on the work done to it, but normally hard to hit a plug.
Turn the motor over by hand, using the fan belt. You’ll feel if they hit. Then crank it over with the starter, with the dizzy HT lead off. If all is well, fire it.
Cheers,
Harv