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What carb is this? 450/525 EXC?

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Hi,

I here have a 39mm carb, which to my opinion is from a 450/525EXC.

It doesn't have a hot start. The number on the side is 3900R...

I have however no clue from what year. Can someone tell me?

Also, what's the funtion of the pipe (to which a hose can be connected) on the side of the carb (see 2nd picture)?

Thanks!

Frank.

DSC02757.jpg

DSC02760.jpg

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Looks possibly like the 03-06 version for the 400/450/525. Not sure though if it could be for the SX or EXC line.

Yes, brass thingy is the crankcase vent. Poisinous gases go from crankcase to intake to get reburnt before being let go into atmosphere, out the exhaust for a cleaner bike.

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I think that brass pipe you speak of is for the crank case vent.

my crankcase and trans breather run to a T and to that

my 08 has a black plastic throttle linkage cover

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Looks possibly like the 03-06 version for the 400/450/525. Not sure though if it could be for the SX or EXC line.

Yes, brass thingy is the crankcase vent. Poisinous gases go from crankcase to intake to get reburnt before being let go into atmosphere, out the exhaust for a cleaner bike.

Thanks! I didn't know the story of the poisonous gases.

About the SX/EXC: did the SX have a hot start, and the EXC not? This is why I presumed it was from a EXC.

I think that brass pipe you speak of is for the crank case vent.

my crankcase and trans breather run to a T and to that

my 08 has a black plastic throttle linkage cover

More people say this, so it's definitely a breather connection. Thanks!

If the throttle return cable opening is blocked off, it my be for the ATV.

Okay. No, it's not blocked off. There's a plastic piece in it, but that is to hold the cable. I saw the same piece on YZF carbs.

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LOL, he edited his post after an hour after I posted that.

I thought the crankcase breather was too allow the air to exit and enter rapidly as the piston moved up and down.

anyways, they're routed to a clean area so no dirt can make it in the motor, or water or anything.

I don't think KTM worries much about oil emissions destroying the health of the riders, especially when we sit on top of a few gallons of gasoline with a 1000 degree piece of metal being routed underneath it

Thanks! I didn't know the story of the poisonous gases.

About the SX/EXC: did the SX have a hot start, and the EXC not? This is why I presumed it was from a EXC.

More people say this, so it's definitely a breather connection. Thanks!

Okay. No, it's not blocked off. There's a plastic piece in it, but that is to hold the cable. I saw the same piece on YZF carbs.

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I don't think KTM worries much about oil emissions destroying the health of the riders, especially when we sit on top of a few gallons of gasoline with a 1000 degree piece of metal being routed underneath it

Yeah, I guess so :p

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