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mixture adjustment other than jetting?

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I just got a 96 xr400. love it, some problems, though. The float was sticking like crazy, even after a good toothbrush/carb cleaner cleaning. I ordered a new float, and I am going to have the carb professionally cleaned. However, I am pretty sure that it was and will be running a little rich when I get it back. I hope not, but if it is, is there anyway to adjust the mixture besides changing the floats out? stupid question, maybe, but I'm just not familiar enough with the bike yet. thanks for any help. (california riding, 0 - 3000 feet).

side note, I am eye witness to the fact that a Yamaha 400 can be ridden on a completely flat tire for at least 15 miles before causing any real damage to the rim. ha ha.

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You have a main jet, a pilot jet, a needle that can be raised or lowered and the fuel screw that all adjust the air/fuel ratio for their respective ranges. With the new float you're gonna have to set it's levels too. PM me with your email address and I'll send you the scanned procedure from the manual.

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thanks,

I have been researching more on the carb, and found out how to set the float: (about14mm). I am also familiar with the jets, and I recently discovered the needle clip can be set to move the needle up or down, but the fuel screw I am unfamiliar with. can you tell me where and how it works? will It adjust the mixture noticebly? or do I need to pull the carb apart every time.

thanks :cry:

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Yeah, there's been lots of discussion on the carb here. A search should get you alot of info. That 14.5mm figure for the float is the minimum drop setting. Set the max drop too, to 19mm.

The fuel screw is located at the front of the float bowl, outside the carb, points down. See it? It adjusts the mixture for the pilot circuit, 0- to about 1/4 throttle. The ideal position is 2 turns out, so you try to install a pilot jet that has the bike running it's best as far as idle, throttle response/power in the 0-1/4 throttle range, at that 2 turns out or near it. It is a fuel screw, meters fuel. In is less/leaner, out is more/richer. If the bike runs it's best at 1 turn out, the pilot jet is too rich, right? Putting in a smaller pilot and reajusting the screw will get you closer to that ideal 2 turns out before the bike starts to run its best. Visa versa if the screw is more than 2.5 turns out, you'd install a richer pilot, right? Got it? Anywhere in a range of 1.5-2.5 turns out is acceptable before rejetting IMO. Any more than 2.5 out and you start relieving the screw of too much of its spring tension and you risk losing the screw on the trail from it vibrating out.

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