bp 7es ngk plugs failing

[Guest William Williams]

have got a lo cost with a kent 1600 engine with twin 40 dellorto carbs. I bought a new set of bp 7es plugs.Two of them have failed No.1 and No.4. I had a couple on champion n9y and they ran ok.I heard that 1600 crossflows like the ngk. The n9y seem to run cleaner but am not sure about fitting them.the ngk have only covered 70 miles. Can some one advise please.

                                                                                                                                         Bill Williams.

[blue]

Back in my escort days we had to run bpR 6es plugs or we had the same problem 

[Guest William Williams]

Thanks have fitted a set of n9yc and now runs without banging and running on three cylinders.

                                                                                                               Bill