I have a 1982 xz 550 and it starts, but only with full choke and a little throtle. This puts it at about 4000rpm. I back off the choke to 2500rpm (about 1/2 choke) to let it warm up. As soon as I get it out of 3000rpm the bike rpms bounces up and down Sparaticly a moderate pace. I have no clue what to do.
some one told me it could be a line problem and to change the plugs
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The most common cause of this problem besides dirty carbs is a laeking YICS box. The YICS is the chrome covered box on the right side of the carbs. It is a dual chamber box designed to help "swirl" the intake gasses.
If one or both of the chambers is leaking the bike will "hunt" for an idle.
The fix is to carefully cut the box in half along its seam and make a gasket then seal the two halves toogether again with red RTV. Let it dry for 24 hrs.
A quick check is to hook up a length of hose to each port on the YICS and submerge it. Blow in each of the hoses. If air goes in one and out the other, you have an internal leak. If you see bubbles, you have an external leak. Either waym the fix is the same. See www.xz550.com for more info about it.
YellowJacket
Testimonial: "that web site was very help full. i think i have more than one problem acting like one.... i am using liquid tape on carb mount life saver!!for crack"
It sounds like the carbs need to be taken apart and cleaned. Bike should start up with just choke .
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Thanks i tryed seafom as a cheaper way to start. It got a lot better. I do not need the choke on to have it idle... but it has to go to the shop to get the jets cleaned........... 2nd Q? is 300.00 a good price to get 2 carbs cleaned?
I got my carbs done 2 times. the 2Nd time for free. ( I am not even using the yinc or what ever it called I used one fuel line to connect ) the rear cylinder will not fire unless i have it 2500 rpm and the tac is still bounces up and down Sporadically. I put new weirs on both and have blue spark. So i know it is not electrical.... I am going to try liquid tape on the rubber carb mount, maybe it has a leak.... There was someone on this form talking about cutting the yellow cpu wire. Is there anny truth in that?
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