why are my plugs fouling? 77 suzuki gs550.?

I need to know why my plugs are fouling. Entire fuel system cleaned last year. Uses NGK B8es plugs. i tried using all new plugs, nothing. Tried riding harder / faster, jiggled the plug wires / cleaned them . Every plug comes out try and black. Pure black on the end like it was burnt. They will not come clean. It is not oil as it has not burnt a drop. The bike runs fine and starts everytime. Plugs foul about every 100 miles. I get approximately 16 miles per gallon.,,, Has anyone else had this issue? i have tried everything from 87 to sunoco 93 and fuel cleaner to no avial. Have tried petcock on prime, res, and run. No change. REPEAT all 4 plugs are fouling,. Any info or insight would be much appreciated,

Update:

I cannot find hotter plugs anywhere. All i can find is NGK B8ES.

would this help?

https://www.denniskirk.com/sudco/ignition-tune-up-...

link to plugs

https://www.denniskirk.com/ngk/spark-plug-b8es.pb8...

3 Answers

Relevance
  • 7 years ago
    Favorite Answer

    fit two grades hotter plugs or iridium plugs with multi electrodes

  • 4 years ago

    call a motor-cycle save and ask. Stripped threads ensue whilst somebody did no longer wait until the motor became into chilly to get rid of the spark plugs AND wipe *by no skill grab on the threads of the recent plugs until now putting them back interior the cylinder head.

  • 7 years ago

    might be a bad fuel pump diaphragm

    could be sucking fuel in the crankcase and causing bad mixture, plug fouling, poor mileage

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