1997 Vmax 500 XT Mid range rough using lots of gas

Curious to know if the worn tubes was the cause. Took my 98 Venture 700 for a ride yesterday and had some very similar issues. Runs very sloppy in midrange, and sucked through half a tank of fuel in no time flat. I was thinking bad reeds at first, but after finding this thread, I'm curious now.
 
After reading this I replaced the needle jets (tubes) and jet needles in our "98" XTC 500. Both parts are discontinued, but they can be still on a dusty Yamaha dealer shelf somewhere. A dealer found my jet needles in southern Wisconsin and needle jets in Canada. Hope there are a few left for you. My sled has always ran great on top end, but has sounded "Garbley" on the lower end of the midrange for a long time. It has more than 10,000 miles on it. Been in the family since new. It now sings in the mid range like it should. Sounds completly different. I have not had a chance to check mpg yet, but I bet I have made a gain. Hope this helps yours like it did mine.
 
@BornYamaha, that's great to hear. Don't forget to keep an eye on the oil pump drive on these engines, as its a problem area.
 
6 mpg problem solved.

I am one of several TY members who have had low mpg problems with their 600 twin engines. It was a big surprise after getting 12 mpg when new. Tried several fixes, but nothing changed much. Then I saw a fix that I'd never heard of and it sounded like it HAD to be what I was looking for. It was the main nozzle fix suggested by 74Nitro. They are rare so get them quickly if you need them. I'm back to 11 mpg and one happy camper. This was a very frustrating problem so thanks
74Nitro for the much needed help.
 
My pleasure! Good to keep these machines running....and running good.
It would be great if Yamaha and / or Mikuni would make another batch of these main nozzles.
 
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