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Discussion Starter #1
I just bought a 95 mxz440 that had an engine swap and a bucket of parts. When I checked out the carbs it came with I was told by a sledhead they were 42mm mikuni's instead of the stock ones...Does anyone know how to tune these.....Lean/ Rich screw settings.....I understand the jets might have to be replaced with smaller ones, yet for now I just need to tune the carbs...T

Thanks so very much..............
 

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journeyman sled/motorhead
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I just bought a 95 mxz440 that had an engine swap and a bucket of parts. When I checked out the carbs it came with I was told by a sledhead they were 42mm mikuni's instead of the stock ones...Does anyone know how to tune these.....Lean/ Rich screw settings.....I understand the jets might have to be replaced with smaller ones, yet for now I just need to tune the carbs...T

Thanks so very much..............[/b]
is it a liquid cooled 440?
 

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Discussion Starter #3
is it a liquid cooled 440?[/b]
No it was swapped with a 583....Liquid cooled...maybe a 96 motor???
I just out the carbs on, new throttle cable and it fired right up with a big backfire...
Can you help...I dont want to have to use my fire extinguisher or homeowners insurance tonight.....HAHAHAHA
svensdad-
 

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I just bought a 95 mxz440 that had an engine swap and a bucket of parts. When I checked out the carbs it came with I was told by a sledhead they were 42mm mikuni's instead of the stock ones...Does anyone know how to tune these.....Lean/ Rich screw settings.....I understand the jets might have to be replaced with smaller ones, yet for now I just need to tune the carbs...T

Thanks so very much..............[/b]
The only thing the air screw affects is idle mixture. The throttle stop screw sets your idle speed. The only way to "tune" these carbs is to replace the jets. The needle position can be moved up and down which controls your midrange mixture, but if your pilot jet and main jet are wrong no amount of moving the needle will help you. You probably also have the wrong needle jet and jet needle, but who knows. I don't have any more specific info than that. My sleds have never backfired so I don't know where to start with that. You are probably too far into custom land where nobody can give you a definitive answer and you'll need a lot of trial and error...but who knows we have some smart people here.
 

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journeyman sled/motorhead
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backfire or just spit out the carb? which could be a lean spot. I don't like tuning carbs over the net.
 

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Discussion Starter #6
The only thing the air screw affects is idle mixture. The throttle stop screw sets your idle speed. The only way to "tune" these carbs is to replace the jets. The needle position can be moved up and down which controls your midrange mixture, but if your pilot jet and main jet are wrong no amount of moving the needle will help you. You probably also have the wrong needle jet and jet needle, but who knows. I don't have any more specific info than that. My sleds have never backfired so I don't know where to start with that. You are probably too far into custom land where nobody can give you a definitive answer and you'll need a lot of trial and error...but who knows we have some smart people here.[/b]
 

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Discussion Starter #7
The only thing the air screw affects is idle mixture. The throttle stop screw sets your idle speed. The only way to "tune" these carbs is to replace the jets. The needle position can be moved up and down which controls your midrange mixture, but if your pilot jet and main jet are wrong no amount of moving the needle will help you. You probably also have the wrong needle jet and jet needle, but who knows. I don't have any more specific info than that. My sleds have never backfired so I don't know where to start with that. You are probably too far into custom land where nobody can give you a definitive answer and you'll need a lot of trial and error...but who knows we have some smart people here.[/b]
I thought maybe when I put the new throttle cables on they might be off....could this cause it backfire?????
 
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