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Discussion Starter #1
i have a 95 zr580 boerd to 600 piped and 42 mikuni carbs instead of 38 im having a little trouble with it running it idles good when u touch the gas it bogs and u got to play with it tu rev it up ive changeds main jets and messed with the needles any sugestions would really help and i should say i bought this sled like this with all the work done and this problem
 

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if your problem is when its at idle and you give it the gas,,, changing your mains will not help at all. You should be running on your pilot jet at this point. I would look into that and making sure your air screw is adjusted properly.
When you adjusted your mains and needle,,, where the mains that were in the carbs from the carbs originally, or did they come out of the stock 38's that were on it??
 

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Discussion Starter #3
I HONESTLY DONT KNOW TO MUCH ABOUT THIS SET UP ID LIKE TO FIND OUT IF 38 AND 42 CARBS TAKE THE SAME SIZE JETS CAUSE I REALLY DONT KNOW WHAT SIZE PIOLET JET IS IN IT AND ID LIKE TO GET A JET KIT I SHOULD GO A LITTLE SMALLER WITH IT RIGHT
 

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smaller than??? depends on what is in there figure you had a 580 and now its bored to a 600,,, so there is 2 different size jets. your motor is now piped, so that will affect your jet sizes also. DO NOT GO TOO SMALL. Going small is going to give you less fuel and more air,,, it will burn hotter and your taking a chance on burning it down. You main will only affect your top end,,, so run it wot and then cut your power,,,, then pull your plugs and see what they look like. They should be a nice golden brown. But at idle (which is where your having problems) your main jet will not help at all. Its your idle circuit that is working there. That consists of your pilot jet and your air screw setting. Who did your motor work?? Who put the carbs on?? I guess you could get into a lot of issues,,,, with the motor being modded,,, now your clutching will probably be off. I guess you start with the motor and then get into the clutching from there though.
 

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if you turn your air screw out more than 1 1/2 turns. what does it do ? if it seems better i'd get a couple sizes smaller on pilot jet and try. as far as adjusting turn in till it starts messing up then turn out till it messes up. find that sweet spot in between.
 

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Stock it came 40mm carbs, not 38's. Does anyone have a simple way of determining if it is a rich bog, or a lean bog? One other thing to consider is the carb slide cut-away. In 95 the stock cut-away was a 3.0. I don't know if that is as lean as they get, or if they make a 3.5 cut-away, which would be leaner. A 2.5 and 2.0 cut-away will be richer.

The larger diameter carbs are going to be more difficult to tune, especially at low throttle opening because the larger venturi diameter will result in lower venturi air velocity. The lower venturi velocity makes for a weaker signal on the fuel and reduced atomization at lower engine speeds. You might need a richer pilot jet to make it easier for the weak signal to pull fuel, and maybe go richer on the air screw adjustment, which should mean fewer turns out.
 

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Discussion Starter #7
i went down one size on the piolet jet it somewhat went away it used to bog up to 3500rpm and now after 1500 to 2000 it clears up i dont know if i should go one more or not i tried messing with the mixture screw it helped a little and do u know at what rmp this thing should idle at oh yeah the plugs are a dry tan color this is ok right
 

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A good hot idle should be 12 - 1500. Plug colour wonèt help you at idle settings. Make sure the carbs have been synchronized.
 
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