Fuel mixture screw assembly help

meyekj

meyekj

XS400 Enthusiast
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As I was disassembling my carbs for cleaning I pulled out the fuel mix screws without realizing there was an o-ring and washer in addition to the spring. I have them, but I didn't see in what order they were assembled. Can someone help me? The old schematics are too blurry to tell and a a quick search didn't pull anything up. I have a '78 2E, but the carbs are newer (still BS34's but not sure what year they came from).

Thanks.
 
No the 77-79 xs400 carbs don't use a o-ring. Just the needle and spring. The 80-82 uses a o-ring and washer.
 

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I knew my carbs were a bit newer than my bike, but I hadn't really looked into that yet. Thanks for pinning it down for me. My screw has less threaded area than the one you show in the photo.
 
Then you want this. Also check to see if your o-ring is stuck at the bottom of the hole. A lot of the time they are and people stack two on top of each other:wink2:
 

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Yes, that's it. Great tip about checking for additional o-ring, too! Responses like yours make this a great forum. Thanks.
 
Which screws? a jet will be done differently than the top of the diaphragm housing? On the engine? or carb? Frame? This is a Fuel mix screw topic? I hope it isnt that screw.
 
You can try a micro drill. Start with a clear pilot hole and measure the size with a bit that fits in it. Then use that size to drill out the hole with the broken off tip in it. After you get the hole use the next few sizes up to give it a tapper for the needle to seat in the hole. Just remember not to give the larger size bits a lot of pressure you don't wont to drill it through.
 

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