yamaha blaster with weak spark running rich

buttermesteezy

New Member
Jul 25, 2011
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bobcaygeon
hello i have a 1989 yamaha blaster bored .40 over and it was running fine untill it stalled out and then it had no spark i put in a new plug and it ran fine for about 4 hours and after i parked it it wouldnt start up again and when i checked the spark it was a weak light blue spark. when i rev it it isnt very responsive at all and it will just stall if i put it into gear. its also running to rich and smoking and it just fouls the plugs and i think the spark plug gap keeps getting messed up somehow because when i take the plug out and kick it over it has no spark unless i adjust the gap to make it a bit smaller. i am running br8es plugs in it. are you supposed to run the normal plugs in it even if it is bored out? if anyone knows anything that might help it would be greatly appreciated i hate having to take it in to get fixed because i am usually able to fix everything myself.
 
Only way gap gets larger is by the electrode burning away which takes 30-40,000 miles on a car. Clean all connections and grounds and use dielectric grease on them. Trim1/4" off end of spark plug wire and re-install plug cap. It gives you a fresh contact there.
 
Lose the BR8ES resistor plug an replace with the specified B8ES. If you are running rich the resistor plug tends to foul more easily.