Engine Pinging-81 1000LTD, jetting changes?

I just bought a completely stock 81 1000 LTD w/ 33k miles. I removed and thoroughly cleaned the carbs, set the float height, adj the valves, new plug wires and caps. I also did the 12v relay trick to power my coils w/ full battery voltage and that helped alot! I'm now getting some pinging when running more throttle up hills or pulling past 70mph in top gear. I was given the larger (127) mains and the adjustable needles that came with the "J" model that year. Any reccommendations on jetting changes I should make? This is my first day on your forum- Looks great!

Have you tried using premium gas to see if the pinging stops? Ed

Yes, I'm running 93. I oiled the mechanical advancer and that seems to be working fine as well.

I'm not familiar with the ignition on the newer bikes, but is it possbile to retard the ignition timing a tad to see if that helps? Ed

I believe it's non adjustable. I like your bike! I ownwed a 77 kz650 c1 back in 83 until a lady took a left turn in front of me and sheared the right side of my crank (the bike's) right off:woohoo: That was an awesome bike. had gobs more power than my 73 honda 500 four!

Saggs wrote: I just bought a completely stock 81 1000 LTD w/ 33k miles. I removed and thoroughly cleaned the carbs, set the float height, adj the valves, new plug wires and caps. I also did the 12v relay trick to power my coils w/ full battery voltage and that helped alot! I'm now getting some pinging when running more throttle up hills or pulling past 70mph in top gear. I was given the larger (127) mains and the adjustable needles that came with the "J" model that year. Any reccommendations on jetting changes I should make? This is my first day on your forum- Looks great!

First of all the "relay mod" is not necessary on these bikes. It may have some use on the older bikes. If you have pinging with ANY gas let alone premium, you have other problems. That bike should run fine on 87 octane with out any detonation. Do you have the right plugs in it? What position do you have the needles on and what is the # on the needles. Here in the US not even the police bikes came with the adjustable needles. Those were however available in Canada on almost all bikes.

Before the relay mod i was only getting 10.3v at the coil now I'm seeing 12.5v so it did help in this case. The bike has the stock needles for the LTD that year. Non adjustable and I'm running B8ES plugs also has the stock 37 pilots. The standard J model had different cams and came with 127.5 mains with a 5 position needle. I have these parts and could use them if it might help?

Do you have the stock airbox or pod filters?

Otakar- yes i have the stock airbox. The pinging is not like a can full of marbles being shaken but a slow knock, ping kinda sound mostly at near full throttle when in high gear. not sure if that helps? I have yet to sync the carbs but i dont think will matter. Thx

I am just trying to determine why you are detonating at hi RPM. If detonation is actually what it is. I wonder if you have a broken valve spring and one of the valves starts to float at the higher revs. Syncing the carbs would only affect the idle. It would have absolutely NO affect on hi Revs. I would also make sure that the diaphragms in the carbs are properly installed and also that they have no holes in them.

Saggs wrote: ...stock 81 1000 LTD w/ 33k miles...set the float height...getting some pinging when running more throttle up hills or pulling past 70mph in top gear....

Does adding some choke reduce the pinging?

If not already done, would perform the clear tube test to assure float bowl fuel levels are within specs.

A too low fuel level may result in pinging due to lean mixture, even with otherwise perfect carbs and perfect fuel supply.

The optimal measured float height is whatever height results in the correct fuel level.

Good Fortune!

Saggs wrote: I just bought a completely stock 81 1000 LTD w/ 33k miles. I removed and thoroughly cleaned the carbs, set the float height, adj the valves, new plug wires and caps. I also did the 12v relay trick to power my coils w/ full battery voltage and that helped alot! I'm now getting some pinging when running more throttle up hills or pulling past 70mph in top gear. I was given the larger (127) mains and the adjustable needles that came with the "J" model that year. Any reccommendations on jetting changes I should make? This is my first day on your forum- Looks great!

"pinging" is ignition/combustion related. Your jetting really doesn't affect detonation. Just to be clear on your description of "pinging" you are talking about cylinder detonation correct ?