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Old 01-13-2008, 08:25 PM   #1 (permalink)
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Mikuni carb needle adjustment

When I was having my bogging problem, my friend said to look at where my needle was set, there are 5 notches and it was on the 4th, he said to move it to the second to lean it out more, bottom line was one of my carbs were plugged up, now I am conserned of this needle adjustment, the sled runs great I dont want to burn it up running to lean, I usually ride from 2500 to 6500 feet if that makes any difference, what are the proper adjustments I should be using on these carbs, thanks
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Old 01-13-2008, 08:28 PM   #2 (permalink)
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What you want is a dry, dark brown color on the spark plugs. If they are light tan to whitish, move the clip lower.
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Old 01-14-2008, 07:47 AM   #3 (permalink)
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so what I am gathering that most all depends on spark plug color, before I cleaned the one carb, the other plug was a a lite chocolate color, not white, I will check them again and follow your instructions, Thank you
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Old 01-14-2008, 08:02 AM   #4 (permalink)
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also should this be done at the elevation I am running as my house is at 1100 ft, would be hard to work on sled in the field
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Old 01-15-2008, 12:29 PM   #5 (permalink)
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first thing i would look at if your sled is bogging is to see if your pilot and main jets are clear.
as far as your needles go, moving the clip from position 4 to position 2, you are making it richer, not leaner. Raising the needle (lowering the clip) allows more fuel to the motor and lowering the needle (raising the clip) allows less fuel.
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Old 01-15-2008, 01:34 PM   #6 (permalink)
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correct

yes I raised the clip to second notch from top, to drop the needle, my explaination was just not right
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Old 01-15-2008, 07:50 PM   #7 (permalink)
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well, did it get rid of the bog?
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Old 01-16-2008, 07:44 AM   #8 (permalink)
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Yes, the bog is gone, dirty carbs & improper adjustments, lunging was the belt, I just want to make sure that I am at the proper adjustment to get the plugs to burn right,I am really parinoid of this burning a piston thing, I am going up and run the sled this weekend and make my final adjustments if needed, the sled runs great now, but no where to open it up at home,I just have a small circle, didnt know if I should run it up in my stand
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Old 05-21-2010, 07:45 PM   #9 (permalink)
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Mikuni carb on a 72 arctic cat 340

Hi guys im all new to this snowmobile two stroke thing. Im building a 77 honda odyssey buggy and i have a 72 arctic cat 340 made by kawasaki. It came with a mikuni 30mm. it has a 300 main jet and the pilot is a 35. im having problems reving it up. it takes a while but when i get it up in reves it seem great very responsive but at idle and low rpm it bogs and seems to spit a bit of fuel out the carb (air filter side. does anyone have any suggestions if this is the right carb or am i missing something? please help!!!
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Old 05-21-2010, 07:50 PM   #10 (permalink)
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Originally Posted by giaco View Post
Hi guys im all new to this snowmobile two stroke thing. Im building a 77 honda odyssey buggy and i have a 72 arctic cat 340 made by kawasaki. It came with a mikuni 30mm. it has a 300 main jet and the pilot is a 35. im having problems reving it up. it takes a while but when i get it up in reves it seem great very responsive but at idle and low rpm it bogs and seems to spit a bit of fuel out the carb (air filter side. does anyone have any suggestions if this is the right carb or am i missing something? please help!!!
clean the carbs. is usually all that is
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Old 05-21-2010, 08:13 PM   #11 (permalink)
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Like aduck said. If you have problems at idle or at takeoff, the problem is usually in the pilot jet, as that is the circuit in the carb that controls air/fuel at idle to about 1/4 throttle. Pilot jets are small and the air and fuel passages to the jet are also small, you may have to take a small wire and poke it through the holes to make sure there is no varnish or debris in the passageways.
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Old 08-08-2010, 12:19 AM   #12 (permalink)
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72 Kawasawki

IVE CLEANED THIS CARB OUT AND TRIED DIFFERENT PILOT JETS NOTHINGS WORKING. COULD SOMEONE PLEASE SEND ME ALL THE SPECS ON AN EARLY 70S KAWASAWKI 340CC FAN COOLED CARBERATOR SPECS. I think they used these engins on cheetahs and im not sure what else.
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Old 08-08-2010, 12:24 AM   #13 (permalink)
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Originally Posted by giaco View Post
IVE CLEANED THIS CARB OUT AND TRIED DIFFERENT PILOT JETS NOTHINGS WORKING. COULD SOMEONE PLEASE SEND ME ALL THE SPECS ON AN EARLY 70S KAWASAWKI 340CC FAN COOLED CARBERATOR SPECS. I think they used these engins on cheetahs and im not sure what else.
What is your sled not doing?
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Old 08-08-2010, 06:51 PM   #14 (permalink)
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72 kawasawki

its a project for a 77 honda odyssey buggy im building. I got this 72 340 and it says arctic cat on the top. The guy gave me a mikuni carb whitch was not original. i think its a 30mm and it bogs like **** when it finally revs up it seems ok but only at high revs if it even gets there. I was told to find out what the carburator specs are for that motor and then go from there. thanks

Last edited by BC_Dan; 08-21-2010 at 12:08 PM.
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Old 08-20-2010, 09:07 PM   #15 (permalink)
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The colour of Coffee. Coffe brown.

The Jet needle track is from 1/2-3/4+ throttle. Main jets take over from there.

Again Coffee Brown, is what you are looking for.
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Old 08-21-2010, 05:36 PM   #16 (permalink)
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coffee brown

coffee brown for the plugs right?
I cannot get the carb set up at all could i have a wrong needle or jet in it since the carb wasnt on the engine factory? thats why i was looking to find out what the specs were for the walbro carb that came off it. if i knew then i could put the right parts in the mikuni if need to then i can start from there... its kinda hard right now because i have a feeling this carb is not for this engine at all....

like i said im new to this ive never had a snowmobile so im kinda going at it blind... sorry if my questions seen stupid thanks guys
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Old 08-24-2010, 08:52 AM   #17 (permalink)
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Take a look at the clutching, if the plugs are not overly dark/wet, I think that the clutches may be your problem.
Cleaning/servicing them can really wake up performance.
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Old 11-15-2010, 11:35 AM   #18 (permalink)
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So would I be right in assuming that the top clip would be #1. I have adjusted these before, and know which is richer/leaner, but I am now putting twins on an 800 rmk, and was only told(per slp's jetting charts) to put the clip on #4, along with bigger mains.

Based on the fact that I need to be running richer with the twins, I am assuming the needle should also be fattened up, which would mean top clip should be #1. This is what my little bit of common sense tells me.

Just want to make sure.

Thanks.
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Old 11-15-2010, 03:18 PM   #19 (permalink)
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reving issue

Ok if you have cleaned the carb and tryed diffrent pilot jets i have one question!!! what kind of pipe is on it???? is it the stock 340 or did you make you own ???? if you dont have the correct back pressure the sled will not run or rev out properly
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