Help me read these plugs

[kidtriton]

This is a new set of plugs after about 20 minutes on a brand new engine. Engine ran well at first during break in, but started missing and bogging about 20 minutes into break-in. 1995 ZXI900 , Cyl 1,2and 3 plugs.







[ August 02, 2003, 09:11 PM: Message edited by: kidtriton ]

[stevepaulus]

#2 looks lean.....but is that grey i see on #1 and #3, or just a bad pic?

[kidtriton]

yea, 1 and 3 are actually the ones i was worried about. #2 was still kinda wet from fuel when i pulled it, (i cut it off at WOT) and the 1 and 3 were dry. The last engine lasted about 10 tanks of gas and burned a huge hole in #3 piston, right under the rings and out the exhaust port. I took the #3 carb apart and cleaned it, but something is still not right. Also when the engine idles, if you hold your hand on the head above each cyl., #1 is kinda hot and the other 2 are cool to the touch.

One more thing, all the reed valves looked good, but i did swap them around, so the old #3 reed is on #1, 1 is on 2 and 2 is on3. At first i thought the reed was the problem since the engine was warmer on #1, but then it started running bad and the 1 and 3 plugs look the same.

[ August 03, 2003, 07:33 AM: Message edited by: kidtriton ]

[stevepaulus]

Do a compression test, i bet you burned a hole in the pistons again.

And rebuild your carbs.

If the other 2 are cooler, your running to lean.

[ August 03, 2003, 11:26 AM: Message edited by: stevepaulus ]

[kidtriton]

i looked in the cylinder with a borescope, and didnt see anything wrong. Keep in mind that this engine has only run for about 20 minutes, and this was low rpm running to break it in.

[stevepaulus]

I'mk not sure what would give off that grey color. You could of gotten a bad tank of gas.

Do a compression check just to rule out a bad cylinder.

[CaptToyota]

Fatten up 1 & 3 slightly, and see what happens if you lean #2 a bit.

I don't think there is a real problem with 1 &3,, it appears to be #2 is your miss.

Could be a simple faulty plug, but NGK seems to be a trouble free plug, uless it was dropped or something...

[stevepaulus]

Since when does a faulty plug give off a grey color, i have never seen grey on a plug.

I would be more worried about #1 and #3.

#2 is lean from what i know........the rim is of clean metal, #1 and #3 are just weird looking, i would do a compression test.

[CaptToyota]

1&3 are fine- note the dry soot all way around the rim, and nice dry clean appearing porcelin. That #2 plug has no signs of operating proper, if was lean, the cylinder temps would be real high, leaving a clean appearing porcelin, like 1&3, note the crudded oil bubbled up on #2, there is no cylinder temp to burn it.... lean mix will raise temp, rich will cool it. I still say look at cylinder #2.

[ August 04, 2003, 11:14 AM: Message edited by: CaptToyota ]

[Ignis]

Two questions:

1.) You already had it at WOT only after 20 minutes during the break-in!??

2.) Can someone edjucate me on plug reading? What does the rim tell you, and what does the insulator tell you? Any other tips?

Okay, I guess that was 4 questions. [img]/graemlins/winkanim.gif[/img]

[kidtriton]

Originally posted by Ignis:
1.) You already had it at WOT only after 20 minutes during the break-in!??

Yea, i did a 10-20 second WOT run in order to read the plugs. You cant pull them after putting around for 20 minutes and get a good reading.

[kwacka]

Hi
It looks like to me you have the wrong heat range, 1 and 3 look like they are running too cold, it also looks like 1 and 2 are too lean. I would check your plugs for gap and type. hope this helps also I would not do this test on new plugs as it is not accurate.
Andy

[stevepaulus]

20 miniutes into break in and your going WOT, big no no...... You should of set them a bit rich and finished the break-in process.

Then fine tuned the carbs after the break-in.

For one thing, during break in you are running extra oil, so your not going to get accurate plug readings anyways.

[ August 11, 2003, 08:41 PM: Message edited by: stevepaulus ]

[andy v]

you just rebuilt the motor, right? why did it blow up??? the grey is from being too hot. i'd guess you have a blockage in the oiling system of carb #1 and #3, the extra pump pressure is over oiling #2 and causing it to be oily. did you pressure test the motor after you put it together? did you replace the oil pump and prime the lines? is it cooling properly? you should have a NGK BR9ES Solid type plug. the jetting shouldn't have changed and the carb settings shouldn't have to be adjusted after a rebuild. by messing with plug heat range and carb settings i think you are complicating your problems. [img]graemlins/spit.gif[/img]

[stevepaulus]

OR.....maybe his last engine took a crap because the carb settings were never right.

You need to rebuild them and set them to factory specs.

Just my opinion, but it looks lean to me.....isn't running hot mean running rich.