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Thread: XL700 Carbs

  1. #1

    XL700 Carbs

    Looking for some advise here. My '99 Xl700 was stalling off Idle last fall so I rebuilt the carbs this winter. I used Mikuni rebuild kits, and replaced the need & seat with 1.8 mm ones from SBT (stock is 1.5 mm). I found that the high and low-speed adjuster screws were smashed near the ends, which would explain the stall when I hit the throttle, so I replaced them with new ones from powersportsuperstore. Stock valve seat size is 1.5, and pop-off pressure is 55 psi, so according the the Mikuni sbt manual with 1.8's, I should have somewhere between 55 & 32 pop off pressure, and I have 38 on each, so good right? I adjusted the needles according to the manual (5/8 front, 1-1/8 rear). On the water, idle is good and no stall when you give it the gas, but it doesn't seem like it will get to top rpm's, and sometimes feels like it surges a couple 100 rpms if you hold it WOT. I took it out yesterday with new spark plugs and ran it full throttle for 1 minute, checked the plugs, and they're white (worried yes!). When I turn the screws out (1/8-1/4 turn), I cant get it what I would say above 1/2 max rpm's and the plugs are still white. The more I turn them out, the less rpm's but the plugs seem to stay white and hot. Compression is good at less than 100 hrs. My question is, did changing the pop-off pressure/seat size make it run lean? I figure a bigger seat should run richer?

  2. #2
    Forgot to mention: I checked the fuel lines/valve/filter and all check good.

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