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I'm in need of a good used carb for my 440 xcr. Found the part number to be 3130660. Would a carb off a older 440 xcr work even though it's a different part number?
 

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I'm in need of a good used carb for my 440 xcr. Found the part number to be 3130660. Would a carb off a older 440 xcr work even though it's a different part number?
You can use any similar carb from almost any sled as long as it's setup the same as the original carb. I have many used carbs if needed. My 96 Polaris Shop Manual says that your carbs are VM 34 mm aluminum. 260 main jets, 50 pilot jets, 6DH3 needles, Q4 (286) needle jets, 2.0 slide cutaway. You have two carbs, so they must be the same setup. There can be slight differences in the drilled idle passages between carbs, so be cautious.
 

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Discussion Starter #4
Helps if you post where your'e at.
I'm in Liberty Maine

You can use any similar carb from almost any sled as long as it's setup the same as the original carb. I have many used carbs if needed. My 96 Polaris Shop Manual says that your carbs are VM 34 mm aluminum. 260 main jets, 50 pilot jets, 6DH3 needles, Q4 (286) needle jets, 2.0 slide cutaway. You have two carbs, so they must be the same setup. There can be slight differences in the drilled idle passages between carbs, so be cautious.
Yup that's what I have. Only want to buy one because the other is good. Just made me curious about the different part numbers. I bought one already that was wrong so I dont want to get the wrong one again. They sent me a crab off a 440 liquid none xcr but listed it as xcr so the intake side is way to small to fit the airbox.
 

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Reason I asked was local guy here in Wisconsin has dozens of Carbs and it's true that some carbs have shorter airhorns that other carbs of the same size venturia.
 

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I'm in Liberty Maine



Yup that's what I have. Only want to buy one because the other is good. Just made me curious about the different part numbers. I bought one already that was wrong so I dont want to get the wrong one again. They sent me a crab off a 440 liquid none xcr but listed it as xcr so the intake side is way to small to fit the airbox.
If carbs are 34 mm, the intake bell diameter is smaller than 38 mm. So, are carbs 34 or 38 mm? Airbox should have small diameter outlets if 34.
 

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Discussion Starter #9
Correct mine are 34mm. The one on ebay was off a 93 so I'm guessing that's the reason for the different part number. Did some searching, Is it true that the 550 fans have the same carbs?
 

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Discussion Starter #11
What exactly is wrong with your existing carb?

Think Snow!
Went to clean the carbs and found the prior owner broke the pilot jet off. Inside the carb was completely covered with tarnish and crud. Tried to drill out and tap a torx head in it after solking it in pb blaster but did not work. I drilled it out completely and threaded it for a different style just which does work surprisingly.
 

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Ah, the pilot jet debacle, been there. While I believe the 550 did use a mikuni 34mm for awhile, there are differences. Your best bet is another 96 xcr 440 or a 97 xcr 440. Your carb should be aluminum. The majority of 34mm mikuni are zinc.

Think Snow!
 

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While the earlier xcr 440 did have 38mm carbs, I would imagine porting, pipe configuration, jetting, and even clutching configuration we're different as well. Without other changes you probably wouldn't gain much (if any) performance while using more fuel.

Think Snow!
 

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Reason I asked was I did alot of reading and from what I gathered is they went to 34mm carbs to meet race requirements.
Carbs work on air flow velocity. The higher the velocity, the better the mixture. This is what creates the atomized mixtures needed to break raw fuel into fine droplets so it can more easily turn to vapor when the heat of combustion meets it. Fuel that doesn't vaporize will not burn properly. Big bore carbs on small bore engines do not work well at lower rpm because velocity is too slow at wide open throttle. 38 mm and larger carbs are used mostly on bigger cc engines or very high rpm ones.
 

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Discussion Starter #18
Alright it looks like I'll just stay with the factory setup. Ide like to try and save the carb I guess. Does anyone know what the thread size and pitch are for the pilot jet? I drilled it out pretty dead on so I think I might be able to just run a tap down it.
 

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Alright it looks like I'll just stay with the factory setup. Ide like to try and save the carb I guess. Does anyone know what the thread size and pitch are for the pilot jet? I drilled it out pretty dead on so I think I might be able to just run a tap down it.
Try M4 x 0.7

Thread size and pitch for a Mikuni pilot jet
 
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