Topic: Help Read My Spark Plugs! Yay!

[campbmic]

After visiting with fastbroshii a few days ago my bike is running a lot better. I still have some popping and flat spots and a few questions.

When do you pull the choke switch up, closing off the air to the carbs? Is it only when starting up the bike when its cold outside. Or is it every time you start the bike no matter the temperature outside? After the bike is warmed up do you open the choke all the way up and leave it open?

So on to my spark plug readings. I took some pictures to help with the process;

All four plugs 4,3,2,1 from top to bottom. I don't know why it flipped the picture.


4,3,2,1 from left to right


So any tips on what I should adjust to prevent the popping and getting it running 100% It has a 4-1 which I believe is MAC and EMGO 35MM pods.

Thanks

[scottly]

3 looks lean, 1 looks rich(may be permanently fouled, replace or burn-off with micro propane torch). Make SURE all floats are set to same levels. Check for leaks around the carb-to-head rubbers (spray with WD40 with motor running and listen for changes in idle RPM.

[fmctm1sw]

Here's a good read:  http://www.strappe.com/plugs.html

[fmctm1sw]

After visiting with fastbroshii a few days ago my bike is running a lot better. I still have some popping and flat spots and a few questions.

When do you pull the choke switch up, closing off the air to the carbs? Is it only when starting up the bike when its cold outside. Or is it every time you start the bike no matter the temperature outside?

The up position (on my 350s anyway) will close the butterflies between the airbox and carb body creating a rich condition.  I have to use the choke every time to start my 350s.  I generally leave it on slightly until I get out of the neighborhood.  If it's really cold, it helps me to leave it on a little longer.

After the bike is warmed up do you open the choke all the way up and leave it open?

Yes.  I'm not aware of any circumstance you would put the choke back on unless you had a long stop or something.  Oh wait, there is one time use of the choke helped me after the bike was warmed:  when my idle jets clogged...   

So any tips on what I should adjust to prevent the popping and getting it running 100% It has a 4-1 which I believe is MAC and EMGO 35MM pods.

Thanks

Mine developed some popping when my idle circuit was too lean.  Some of those plugs may have been a little, do a search on plug chops.  Your exhaust and pods may be complicating the matter as well.

[campbmic]

Sorry it took so long I just had a couple hours long struggle trying to replace a speedometer, cable, and thing that attached to the wheel. If #1 is rich and #3 is lean is that something I can adjust with the air mixture screw? I've heard the air mixture screw only adjusts at idle and has nothing to do with how the carbs function at 1/4 to WOT

[scottly]

CHECK YOUR FLOAT BOWL LEVELS FIRST, using the clear tube method. Remember, each cylinder has it's own carb, and, given equal size jets, and equal idle screw(air mixture) settings, should give close to the same plug readings.

[scottly]

Mike, a low fuel level in the float bowl will make a cylinder run more lean, while a higher fuel level will make a cylinder run more rich, all jetting being equal...

Oh, yeah: ditch the #1 plug and start with a new one....

[Inigo Montoya]

On my 77K 750, I shoot for #3 anything else is too rich. But I dont know what bike you have.

[fastbroshi]

   If the motor is cold, no matter what the temp outside, turn on/engage the choke.  See that arrow that pointing forward with "Choke" on it?  It means This Way To Turn on the Choke. 
   Depending on the temp, you'll have to vary the time you leave it on.  If it's nice 72 and sunny you might have to leave it on for 30 seconds or a minute.  If it's cold outside or in the garage, leave it on longer.  And if it's hot outside you can probably get away with starting the bike and turning it off after about 5 seconds.  And lastly if it's like mine you'll have to take into account the moon phase and that butterfly that just flapped its wings over there.