TOPIC:

i recently put some new carbs (vm26's with 112.5 main jets and needle at #3) on my kz900. well, after 80 miles i checked the plugs. absolutely no black soot wiped off on my finger. the insulator is a dark tan color. the tip was squeaky clean. is this normal or a sign of a lean mix? the bike runs crappy when cold but seems to do fine when warmed up. the only thing i noticed was some slight and intermittent backfiring when decelerating. thanks for the help.

Judging by the color you stated, it sounds like it's right in between perfect and slightly rich.

A picture is worth a thousand words....so in not being able to see the "intensity" of the coloring on your plugs, my above assertation is really just a guess.

Check out what NGK has to say about reading plugs .
And don't forget to look at the plug chart on page 2 which actually shows pics of fouled plugs and the condition(s) that cause the fouling. It will probably be of more help than just a "this color is good" or "this color is fouled" description.

i would love to post a pic but i don't have a digital camera. what other conditions would indicate lean? my pipes are painted flat black so i cannot use these as a reference. the head isn't a funky color..it looks normal.

Here's one of the best collections of spark plug pictures I can find on the web.
spark plugs
In fact, go to his home page for a regular plethora of help on maintaining your bike.

pstrbrc wrote:

Here's one of the best collections of spark plug pictures I can find on the web.
spark plugs
In fact, go to his home page for a regular plethora of help on maintaining your bike.

thats a cool site. according to the pics my plugs are good. thanks!!

i hope i do this right. here is a pic of the spark plug in question..

Post edited by: arobsum, at: 2007/03/01 15:27

I honestly can't see anything wrong at all with that plug. Heck, if the plugs in my 650 were even close to that clean I'd probably $*@t myself!

I'm curious, what about that particular plug are you questioning?

I don't see anything wrong with that NGK Plug, but those vise grips need a little tending to.

i've never seen a plug come out that clean!! i was worried i might be running a tad lean. by the way, those vice grips are my best friend!!!

arobsum wrote:

i've never seen a plug come out that clean!! i was worried i might be running a tad lean. by the way, those vice grips are my best friend!!!

What's wrong with this picture,,,?
There does seem to be one thing missing. I see no antiseize lube on the threads.

no lube...good catch!!

arobsum wrote:

no lube...good catch!!

Maybe not.
Not sure how many guys use it. I do; on everything. Even if I did not use it, I would have no problem getting my bike plugs out, because until recently they were only in there for about fifteen or twenty minutes before it was time to change them. _ALL_ of them! And that, my friend gets expensive.