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Old 10-12-2012, 02:13 PM   #70152
ADV in training
Joined: Aug 2011
Location: Albuquerque, NM
Oddometer: 627
Well, it looks like I'm going to be pulling the carb apart again this evening to check this all out. The needle does have a white spacer on it, and I think it was pretty much perfectly round. At least, nothing stuck out in my memory of it. Is the "float needle" that large needle in the slide?
Actually,. I might be better off waiting until I get home to ask questions since I can't check out the pictures at work. Thanks for the info dump, though. It's much appreciated.

Originally Posted by motolab View Post
If the jet needle does not have more than one clip groove, it's not a DJ needle. Is the white needle spacer installed under the clip? If so, is it round, without a notch or being d-shaped?The rubber tip of the float needle should be inspected under magnification. It should perfectly conical, with no witness line evident where it was contacting the seat. If any evidence is visible, or if there is a gap between the bottom edge of the rubber tip and the aluminum portion of the needle, if the plunger is stuck, or if the plunger return spring is sacked out, the needle should be replaced. Not doing so means that the float valve is leaking, or will begin leaking soon.

Emulsion tube wear generally sets in rapidly when the slide guide has worn .010" or more. The way to tell is to measure the depth of the depressions that are located in the bottom corners, concentric to the bore. If they are .010" deep or less, the slide guide should be replaced. '96 and up DR650 emulsion tubes are nickel plated, and so a bit more wear resistant than those found on previous models or KTMs. I don't know how thick the plating is, but if the nickel has worn away to expose the brass, it's definitely time to replace. Replace the slide if the lift hole area has been increased over stock, if there is vertical grooving on the downstream side, or if the needle hole is enlarged and/or ovaled.

See (scroll down for description and links. Click image for high-res view):

Slide guide, used
Slide guide, new
Emulsion tubes, new and used
Slide, used
Slide, new


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'01 DR650
"The impossible often has a kind of integrity which the merely improbable lacks."
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