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Offline larry

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hi rev
« on: February 19, 2011, 03:12:25 PM »
 My 77 550k only ran with choke on.  Had the carbs run through an ultrasound bath.  Had a few leaks out of the float bowl overflows.  Been pulling the float bowl needles and cleaning them which has eliminated the leaks.  Got her to run without the choke on then she revved up to about 3500.  When I rev her with the throttle she'll drop back down some then wants to take off again.  I am running an inline filter trying to keep things clean.  Backed off the big idle adjustment screw 1 turn but that didn't help.  I'm lookin for suggestions.  The choke seems to be operating fine.  And for the record I have not worked on bikes much this is a first didn't want to see it buried in the burn pit in the back grove.
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Offline Terry in Australia

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Re: hi rev
« Reply #1 on: February 19, 2011, 03:33:52 PM »
G'Day Larry, I'm not a 550 guy, so bear with me. I'm presuming that your cables aren't sticking, and you haven't adjusted them so tight that they're lifting your slides? It's best to loosen them right off while you're trouble shooting, then just tighten them (with the engine running) to get the slack out without having them affect the idle speed.

Are the rubber adapters between the carbs and head cracked and perished, could they be sucking air? If they are, this will cause your engine to over-rev, for sure. with the engine running, spray some WD40 on them, if the idle suddenly drops, there's your problem. The more I think about it though, the more I think it might be your cable adjustment. Try loosening them off and let us know if it made a difference? Cheers, Terry. ;D
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Offline Spanner 1

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Re: hi rev
« Reply #2 on: February 19, 2011, 03:43:06 PM »
Check cable adjustment as T.I.A. suggests..... but prob. need a carb vacuum sync. If one slide is sitting a little higher than the rest it will cause the idle to zoom up to 3500 rpm like you describe, that one cyl. will carry the other 3 all the way up the rpm scale......  ;) Do a search for  ' carb sync. '....
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Offline larry

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Re: hi rev
« Reply #3 on: February 19, 2011, 06:41:35 PM »
Thanks for the info.  Sounds like we're going to get a foot of snow tomorrow so after shoveling I'll give your suggestions a try.
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Offline mrbreeze

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Re: hi rev
« Reply #4 on: February 19, 2011, 11:35:10 PM »
Plus one on the carb synch.
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Offline dave500

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Re: hi rev
« Reply #5 on: February 20, 2011, 12:34:31 AM »
lean slow speed circuit or vac leak,the ignition is well up to scratch?
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Offline faux fiddy

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Re: hi rev
« Reply #6 on: February 20, 2011, 01:40:44 AM »
Quote from: larry on February 19, 2011, 03:12:25 PM
this is a first didn't want to see it buried in the burn pit in the back grove.

+1!
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Offline larry

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Re: hi rev
« Reply #7 on: February 20, 2011, 02:58:39 PM »
Played with the cables as was suggested.  This seemed to help,I got her to Idle nicely at 2000 and a bit lower.  But, she still acts up by revving then dropping down to a nice idle, sometimes on her own other by revving the throttle.  A few times she idled down and quit.  Gonna have to see if I can con a local to help with  this scync thing.  Did shift her into gear for the first time since 1983 and knocked all the mouse nests out of that area.  That seemed to go well which makes me feel better.
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