Rich lean question

Yellow_Cad · Oct 10, 2008

My Mk I 850 has a single 34mm Makuni. The plugs have a coating of black soot that is not wet as do the interiors of the pea shooters. The bike does not start with the choke on. I usually choke it for the first kick, take the choke off and it starts in the next kick or two with the choke off. Does all this indicate that my Makuni is set too rich and if so, where exactly should I decrease richness?

mikegray660 · Oct 10, 2008

Yellow_Cad said:
My Mk I 850 has a single 34mm Makuni. The plugs have a coating of black soot that is not wet as do the interiors of the pea shooters. The bike does not start with the choke on. I usually choke it for the first kick, take the choke off and it starts in the next kick or two with the choke off. Does all this indicate that my Makuni is set too rich and if so, where exactly should I decrease richness?

yes - difficult to say the exact cause but generally if it don't need the choke on to start it cold you idle jet is to big or you have the mix screw way off

have to read/looked at panics victory library booklet on tuning the mikunis for twins (available on ebay etc)??

great resource...

geo46er · Oct 11, 2008

Mikuni settings

Greetings,
Recently I have looked into the single Mikuni conversion, being too cheap to purchase the all inclusive pre-jetted kit I bought a "slightly" used mikuni carb off Ebay ($6.75usd + shipping). From various sources I have found varying information, but, with a VM-34mm Mikuni these settings are the most common:
230 main jet
6DH3 needle
P-O needle jet
2.5 slide
35 pilot jet
2 air jet

PS. Hopefully your float level and nedle/seat are operating correctly.

Yellow_Cad · Oct 11, 2008

My 34 mm Makuni has the following set up:

Main 220
Pilot 35
Needle 6DH2
Slide 2.5

What would I change to make it run less rich?

mikegray660 · Oct 11, 2008

Yellow_Cad said:
My 34 mm Makuni has the following set up:

Main 220
Pilot 35
Needle 6DH2
Slide 2.5

What would I change to make it run less rich?

recommended by panic/vistory

pilot 25
slide 3
needle 6DH3
main 260

i got mine from sudco and it has a setup like yours except for needle (was 6dh3)

my bike now after exp/error

pilot 25
slide 2.5
main 260
needle 6Dh3
needle jet P-4

w/ pazon ignition

first kicker...

splatt · Oct 11, 2008

check level of floats first,mine were abit different from side to side,22-24mm from flange face to float arm.2 1/2 turns approx idle mixture.I found I needed a #3 slide,made it very piggy when cold but nice when hot. It used to surge and miss when hot with #2.5 but was alot easier to ride when cold. 159 p2 needle jet 6dh4 needle,230 main .Iam not really sure if main jet is perfect, but I dont like pulling the pin out of a grenade,so i dont run at full throttle to often. 3pilot jet &2 air jet. The sudco kits seem to be very rich,probably wouldnt sell to many carbs if bikes went pop when fitted or US fuel is just total crap.

Yellow_Cad · Oct 14, 2008

Rather than just change everything, I am trying to determine exactly what changable item affects what since the bike starts and runs pretty good just a little rich (causing soot).

cash · Oct 14, 2008

Grief it's years since I last messed with a Mukini.
When are you reading the plugs? have you let it tickover?

Due to the lack of choke, lean it off initially with the air screw then if required fuel screw (if it has one) or pilot jet, lastly the slide.

Cash

Yellow_Cad · Oct 14, 2008

Cash, what do you mean when you say,

"When are you reading the plugs? have you let it tickover?"

cash · Oct 15, 2008

If you are looking at your plugs after the bike has been ticking over the soot you see will come from then and mask anyother throttle position.

What you must do to check the rest of the carbs range is to run the motor under load at the specific opening for a while then without moving the throttle kill the motor and then check the colour.

I think that makes sense?

Cash

splatt · Oct 15, 2008

reading plugs with modern unleaded fuel is just about impossible,you need to full up on avgas and go for a run,o for the days of a nice grey pipe &light tan plugs.

cash · Oct 15, 2008

Grief, you guys must have some funny fuel. However all you need look for is the center porcilain be light tan or even white and that there's no loose heavy black soot. The colour you see on the plug is usually a product of burned oil and additives.

Cash

Rich lean question

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