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Author Topic: ARGH! High Revs.  (Read 1956 times)

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Offline Kixx007

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ARGH! High Revs.
« on: May 15, 2005, 09:27:30 pm »
Well, My bike is still revving to 5g's when I start it with full choke, It doesn't matter if its cold, hot, warm, frozen, on fire, none of it.  If I start the thing with the choke on it revs way up and holds.  I adjusted the screw at the choke cam thing, and that did nothing.. The slides dont even move when it happens.. My guess is there is an air leak somewhere.  Any ideas where is could be??? Or does anyone have ideas as to what could cause this? besides an air leak.
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78 CB550K

Offline cben750f0

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Re: ARGH! High Revs.
« Reply #1 on: May 15, 2005, 09:29:15 pm »
dont pull the choke?...or if you do only till it fires, then put it back to about half?...anyone else?...peace
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Ibsen

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Re: ARGH! High Revs.
« Reply #2 on: May 16, 2005, 06:47:36 am »
I don't know about the 550 carbs, but on the 650 carbs there is a fast idle adjustment screw that controles the idle speed when the choke is on and the fast idle cam is actuated.
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Offline SteveD CB500F

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Re: ARGH! High Revs.
« Reply #3 on: May 16, 2005, 07:07:13 am »
My 550K3 (UK) is similar.  This bike came with leaned-out carbs compared to the F models (and averaged 65mpg on magazine tests). The downside of this is that it is VERY cold-blooded, won't start without full choke and won't run for the first few miles without choke.

I believe (Bryan J confirmed) that there is an adjuster to allow you to set the "fast idle" speed, as the choke actuator includes a throttle lifter assembly.

I haven't had time to look at mine yet, but last time I had one of these (1979) it would sit at 2500rpm on full choke from cold, allowing me to put on helmet, gloves, climb on bike and drive off without it stalling (try that on a 500!!)
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Lumbee

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Re: ARGH! High Revs.
« Reply #4 on: May 16, 2005, 07:59:12 am »
...so what should the bike idle to when choked?  I have a 78F 750, and it idle to about 4kRPM's when choked.  5K doesn't sound that bad to me on full choke.  Am I wrong???
« Last Edit: May 16, 2005, 08:03:42 am by Lumbee »
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Ibsen

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Re: ARGH! High Revs.
« Reply #5 on: May 16, 2005, 08:03:45 am »
If the fast idle can be adjusted, it should be set to below 3000. It does take some time befor the lubrication reaches the top end, and the camshaft journals, and I believe 5000 is too high.
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Offline Kixx007

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Re: ARGH! High Revs.
« Reply #6 on: May 16, 2005, 08:46:02 am »
I have the fast idle screw backed all the way out, to where when the choke is pulled it almost doesnt even crack the slides open. When it starts, It idles slow, then the RPMs just climb and settle out around 5 grand, I can put the choke in halfway and it will Idle around 2500.  It just seems like I should be able to run full choke to warm it up, then back it off halfway. 
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