Could someone post a photo of a spark plug with color for ideal mixture strength

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DennisMo

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With my 850 engine rebuilt I am now looking at the Mikuni. Clearly the choke is leaking as the right plug is soother than the left plug so I have ordered
a new choke plunger. I owl be grateful if I could see some photos of spark plugs where mixture strength is close to ideal.

Mine are sooty.
With thanks
Dennis
 
Could someone post a photo of a spark plug with color for ideal mixture strength
 
Many thanks.
With my Mikuni I am running to rich at low rpm and have sooty plugs.
If I lean out the low speed circuit to get rid of the sootiness, I get lots of exhaust pops on
overrun and when bike first started from cold.
The idle air screw is about 1 1/4 turns out from its seat to stop the popping.
So I thin this tells me it is time to go for a larger size idle jet
I am going to change the idle jet to next size up before reporting back
Thanks again
Dennis
 
Thanks for asking. It is a VM34
I have listed all below but what I want to do first is replace the choke plunger, adjust idle circuit, check the plugs and then ask the forum!
The right plug is sootier than the left.
I suspect the idle jet is too small.
Also I experimented and dropped the needle a notch at a time. Needle is now dropped as far as it can
and there is no lag/hesitation when I crack open the throttle. So from what I read, it may be I eventually might look to a smaller main jet but then there
is the main jet air corrector that may be the place to start.
In the meantime, if you want to share any observations with me, I am grateful
Thanks
Dennis

Idle jet 30
Air corrector 2.0
Needle 6DH3
Jet 230
Cut away 2.5
Air Corrector 159 P0
 
DennisMo said:
Thanks for asking. It is a VM34
I have listed all below but what I want to do first is replace the choke plunger, adjust idle circuit, check the plugs and then ask the forum!
The right plug is sootier than the left.
I suspect the idle jet is too small.
Also I experimented and dropped the needle a notch at a time. Needle is now dropped as far as it can
and there is no lag/hesitation when I crack open the throttle. So from what I read, it may be I eventually might look to a smaller main jet but then there
is the main jet air corrector that may be the place to start.
In the meantime, if you want to share any observations with me, I am grateful
Thanks
Dennis

Idle jet 30
Air corrector 2.0
Needle 6DH3
Jet 230
Cut away 2.5
Air Corrector 159 P0
Click to expand...
Both plugs should inspect identical with a single Mik . Inspect your right plug connectors and HT lead .
Remove the air filter , do a long run and inspect again , using new plugs .
Air jet could be less , a 1.1 .
All rubber ages , including float needles . Replace .
 
All rubber is new. Manifold and float needle.
Choke plunger is suspect....

So here is what I do not understand. I can make the idle jet bigger or the air corrector smaller. But how does one decide?
 
Rich running . Replace the float itself and your suspect choke plunger .
I love spending your money .
Again , if one side , right , running sootier , then concentrate on getting a strong spark there , as it is a single Mik .
Put a voltmeter to the battery . How old ?
 
Float is new! Battery is 2 years old. Battery is on a CTek charger when bike at home.
Headlight always on when running and voltmeter on bike always above 13.5 volts unless turn signals on!
I will report after I get the new choke plunger.
Dennis
 
It's worth noting that virtually all spark plug color charts are for pre-unleaded fuel. There is far less color differences with unleaded fuel. The various color ranges don't appear with unleaded fuel. ALSO plug readings are only "accurate" based on a full throttle load - preferably up hill (or on a dyno) - and the ignition switched off when the bike is still accelerating. Slowing down/idling changes the appearance. The pics do NOT apply if you just remove the plugs in the garage after getting back home.
 
MexicoMike said:
It's worth noting that virtually all spark plug color charts are for pre-unleaded fuel. There is far less color differences with unleaded fuel. The various color ranges don't appear with unleaded fuel. ALSO plug readings are only "accurate" based on a full throttle load - preferably up hill (or on a dyno) - and the ignition switched off when the bike is still accelerating. Slowing down/idling changes the appearance. The pics do NOT apply if you just remove the plugs in the garage after getting back home.
Click to expand...
They won't listen.
 
But if you are just putting around, riding like some people normally do, and you come home and pull the plugs , the plug color will tell you if it is rich or lean or whatever while you are just riding it as you normally do. Which is more relevant to most people than worrying about mixture when flat out, which rarely may occur. Then you can adjust the needle jet, needle or slide, etc, to suit. Getting the main jet close to correct is easy compared to the rest. Graham.
 
Whatever the colour if you do not stop immediately at a particular throttle opening held for 1/4 mile its as worthless as tea leaves. Take it to a dyno or fit an exhaust temp gauge.
 
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