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View Full Version : spark plug black! is it normal?


cyba888
10-24-2003, 11:21 PM
I havent rode my quad for awhile so I had problems starting it. So I took out the spark plug and the thing was black. Cleaned it a bit but still black and tested it. There was a little spark only but not like how its suppose to be when brand new I guess. I believe the spark was so thin you could barely see it. New spark plugs suppose to light up really blue and be noticable correct?
Do you think I need a new spark plug?
JOEX
10-25-2003, 05:51 AM
Originally posted by cyba888
Do you think I need a new spark plug?

Yes.
trailburner
10-25-2003, 06:19 AM
yes put a new plug in. & if your plug is black maybe your runing alittle rich???
Bill Fuller
10-25-2003, 07:12 AM
Originally posted by trailburner
yes put a new plug in. & if your plug is black maybe your runing alittle rich??? ditto
dannyboy20
10-27-2003, 04:29 PM
is running rich mean not enough fuel ?
Bill Fuller
10-27-2003, 04:40 PM
To much fuel.
dannyboy20
10-27-2003, 05:44 PM
well i checked my plug and it ws black. And i have a filter and slip on. You get too much fuel when u re-jet correct ?
trailburner
10-27-2003, 06:48 PM
It depends ......if you jeted up or down..what size main do you have in right now???
dannyboy20
10-27-2003, 06:55 PM
stock i havent touched the carb
trailburner
10-27-2003, 07:22 PM
It doesn't make sense to me if you have a slip on & never touched the carb It shouldn't be runing rich.....:confused:
is your filter clean???
dannyboy20
10-28-2003, 04:00 AM
yes i clean it in a regular basis. It doesnt make sense to me eather.
dannyboy20
10-28-2003, 08:01 PM
:confused:
Bill Fuller
10-29-2003, 05:09 AM
Recheck with a brand new plug.Don't make any adjustments based on an old plug.When in doubt richer is always better.Ride it and see what it "feels" like.
MOFO
10-29-2003, 06:57 AM
Yep, I'd much rather have my bike rich than lean...
cals400ex
10-29-2003, 08:31 AM
i bet its rich from you having problems starting it. it is probally just flooded. i would change the plug and ride it. look and you plug and see what color it is after doing a plug chop.
dannyboy20
10-29-2003, 04:20 PM
well i have a 155 main in now with 12 disks and it whitish ????
trailburner
10-29-2003, 07:36 PM
About the only thing you can do is keep going up on the main until you get a tan color[like a paper bag] a 160 no bigger than 165 should put you right on the money....;)
PS: Do you run with the air box lid on or off???
dannyboy20
10-29-2003, 09:01 PM
on. I dont think im running to lean ?
MyIce
11-09-2003, 12:00 AM
question....

If my 400 is infact running rich and I want to adjust the air/fuel mixture. Do I adjust the small screw on the carb? (the one w/ the overflow line coming out of it) and which way do I turn the screw to get it set to zero so I can do the 2 and 1/4 turns.... right = close, left = open???


Thanks,

My plug was fouled and black smoke has been coming out of the exaust, could it be a carb issue as well?
JOEX
11-09-2003, 04:29 PM
Originally posted by MyIce
question....

If my 400 is infact running rich and I want to adjust the air/fuel mixture. Do I adjust the small screw on the carb? (the one w/ the overflow line coming out of it) and which way do I turn the screw to get it set to zero so I can do the 2 and 1/4 turns.... right = close, left = open???


Thanks,

My plug was fouled and black smoke has been coming out of the exaust, could it be a carb issue as well?
The mixture screw is on the bottom of the front part of the carb, behind the idle adjustment screw. It is very difficult to get to but it can be done.

Screw it in clockwise until it just seats the unscrew it to where you want it. Stock is 2 1/4 - 2 1/2 turns out.

Joe
cals400ex
11-10-2003, 08:54 AM
Originally posted by dannyboy20
well i have a 155 main in now with 12 disks and it whitish ????


you say its whitish, but is that from your fuel skrew, needle, or mainjet setting??? just because your white on your plug does't mean the mainjet is too small. take the bike out and floor it until you get to top speed. quickly pull in the clutch and kill it. take the plug out and look at the color. i find my bike to have best power when you see a small color change right on the bend of the plug. it will probally change from a tan/brownish to gray. since i jet mine so best power, my plug won't be brown in the tip. if it is brown on the tip i will go down on the mainjet until you see a slight color change right on the bend. with your mods, i can't see you needing bigger than a 158 keihin( that is if you use keihin and not dynojets) even in the coldest winter. if you want to jet it a little rich so it runs cooler, you can put in a 165 keihin for example and it will run just fine. you will probally get alittle darker or browner plug, you just won't quite have as much power in the upper gears. good luck