Spark Plugs

Greetings!
Got a question for you to ponder, have a '75 Z1-B 900 has over 58K miles on it, obviously rings are not as good as they once were...so....if B8ES is stock plug and bike isn't lean, would running a little hotter plug ..say a B7ES hurt? Your thoughts? Even hotter?

Just trying to get a little more mileage out of it before an overhaul!!
Regards
TennesseeZ

Stick with what you have ED (B8ES) for a hotter plug isn't necessarily going to buy you additional miles before the top end overhaul. Possibly do more damage then good especially at higher speeds.

The OEM manual warns of hotter plugs (B7ES), they did that for a reason. After I've vaporized a piston and destroyed my engine top end :pinch: :whistle: :pinch: you don't want to go there... No, I wasn't running hotter plugs but it has made me think about performance builds a hell of a lot more for a street rider.

If you have ideal spark plug conditions (Base ring lightly sooted, ground strap 50/50, ceramic light brown to light charcoal gray etc...) then ride her till she drops or better yet, get off you ass old man and get the top end overhauled... :laugh:

Just my two worthless cents... :blush: :laugh:

OMR

Old Man Rock wrote: Stick with what you have ED (B8ES) for a hotter plug isn't necessarily going to buy you additional miles before the top end overhaul. Possibly do more damage then good especially at higher speeds.

The OEM manual warns of hotter plugs (B7ES), they did that for a reason. After I've vaporized a piston and destroyed my engine top end :pinch: :whistle: :pinch: you don't want to go there... No, I wasn't running hotter plugs but it has made me think about performance builds a hell of a lot more for a street rider.

If you have ideal spark plug conditions (Base ring lightly sooted, ground strap 50/50, ceramic light brown to light charcoal gray etc...) then ride her till she drops or better yet, get off you ass old man and get the top end overhauled... :laugh:

Just my two worthless cents... :blush: :laugh:

OMR

Yup, good advice

Run it in the higher rpms a little more if your plugs are dark and see what happens. Wouldnt use hotter plug - even with oil intrusion, its the age old trick to kill a half-decent motor. :laugh:

ed spangler wrote: ... '75 Z1-B 900 has over 58K miles on it, obviously rings are not as good as they once were...so....if B8ES is stock plug and bike isn't lean, would running a little hotter plug ..say a B7ES hurt? Your thoughts? Even hotter?
Just trying to get a little more mileage out of it before an overhaul!....

Would concur with others in urging NOT to run a hotter plug.

With brand new plugs, does the bike perform well on all four cylinders (at least until a plug fouls out)?

Is there lots of blue smoke from the exhaust?

Is there a lot of smoke from the crankcase breather?

Is it for certain that the plugs are oil fouling, and that the fuel mixture isn't too rich and thereby adding more black deposits on the plug?

If not already done, would assure both oil and filter are fresh.
And with fat-blue properly timed sparks.
And that valve clearances are within specs.
And that air filter is clean and free from any obstruction.

If not recently done, would perform the clear tube test to assure float bowl fuel levels are correct (especially not too high).

After all above items have been attended, could experiment by slightly leaning the pilot circuit (turn each pilot air screw out counter-clockwise, say 1/4 turn) to see whether the leaner mixture might help avoid early plug fouling.

Good Fortune!

I may be fighting a similar battle. I've been working toward putting a bike back on the road after at least a decade of not being ridden.

I've had some timing troubles, and may have over choked it to start the last time?

Seems to want to drop out a cylinder (plug fouled) at lower rpms. Rev it up or ride faster and it clears up. Came back on the way to work this morning. Didn't want to limp it home on 3 and risk damage.

Plugs just look black on cylinder 4. Suspected ignition coil problems, replaced with new and new wires. Plug still fouled after about a 10 mile ride as leisurely traffic pace. Stays good if I'm on the gas more.

How do I diagnose oil vs. carb adjustment?