engine pinging

Hey Guys,My 82 kz1000p runs good when it warms up but
after 8 to 10 miles it pings when you roll on the throttle
Im using 87 octane fuel.Could it be timing or valve
clearance issue?The timing advance is clean and lubed.new
plugs and caps,did a dark test on plug wires they are
ok.its been about 6000mi.since it had a major service.
(all topend gaskets,valves adjusted,new cam tension springs,
carbs rebuilt,new holders,oil and filter change)I did a
search but didnt find anything.Any info would be greatly
appeciated! Will post a pic soon. Thanks, Roadsoul

Did you check your spark plugs? Are they burning good,Not carboned. If a Bike runs a little on the lean side more heat is built up causing pre-detination or ping. A cooler plug might help. You'll get more help in a minute.

I'd suggest trying a set of NGK B9ES (colder sparkplug) gapped between 0.028 to 0.032 and see how it runs.

I recommend you get a timing light and see if your timing is correct from idle up to 4k RPM. The FSM has the timing advancer curve and I will wager an old advancer is not following it very well. Anyway, mine was way off.

As for pinging, I would try better gas. My 750 never ran right on 87 so I don't feed it that.

Ditto on looking at the plugs to see if they are running too hot.

Try 93 octane to see if it still pings. Premium fuel is much cheaper than replacing pistons. Ed

92 or 93 octane is barely high enough for engines built to run on 100+. Use the highest you can find and you should be good. Also as someone else suggested, check the timing.

My 77 1075cc, 10.25 compression kz1000 pings on hot days with 93 octane in it. I can't imagine what would happen if I ran 87.

If the advancer is the style in pic below, the F mark at idle rpm should align with the permanent case mark when viewed under a timing light.

Excessive carbon deposits in the combustion chamber might raise compression psi too high. If not already done, could perform a compression test to help determine whether there might be excessive compression.

As noted, NGKB9ES sparkplug is indeed one step cooler than the standard NGKB8ES. However, the reported history doesn't mention plug brand or heat range. So would first assure that NGKB8ES -- the correct sparkplug -- is installed before further diagnosing cause of the pinging.

Good Luck!

{Click on image to enhance view]

you answered the question yourself you should be running as high an octane fuel as you can buy with out resorting to something like e-8590+ octane if at all possible in the heat of the summer air cooled motors have enough problems with out dealing with low quality fuels.

If the bike is stock, 87 octane is what it was designed to run on. If you installed new fuel line make sure there are no kinks. Also some inline gas filters can slow the fuel flow.

Hey Guys,I replaced the fuel filter and checked the spark
plugs.no.1-rich,no.2-good,no.3-lean,no.4-good.Ive tried
all three grades of fuel,it seems to do best with 89 octane.
I tweaked the carbs, it runs good but still pinging but not
as bad.Im gonna borrow or buy a timing light this week and
check the timing,Im convinced thats the problem.I still
need valve clearance checked and adjusted if needed and
check head torque.If anybody knows a good kz mechanic in the
Houston area please let me know.A special thanks to all with
their great responses, I truly appreciate it.Ill keep you
guys posted what I find out. Thanks again, Roadsoul

Whens the last time you had your carbs sync'ed.?

The carbs were synced when they were rebuilt less than
2 yrs ago.But I forgot to mention that I noticed carbon build up on the top of the pistons when I checked the plugs.A guy told
me about a product called ring free from yamaha that will
safely remove carbon from the top end.All the bike shops
are closed on mondays around here so Ill hit the yammy
dealer tommorow and check it out. Thanks,Roadsoul