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Throttle won't come back to idle

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McMaleus
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Throttle won't come back to idle

McMaleus
Hey guys - having some throttle problems.  The engine won't come back to idle as it should.  Seems to want to stay at 3500 RPM.  I've removed and cleaned the throttle and choke cables but that didn't seem to work.

If I twist the grip manually it'll come back down (so I don't think it's an idle setting issue) but it won't go automatically.  It also seems to like to creep up from idle to about 3500.  I'm beginning to wonder if the choke is sticking (doesn't seem to be), or if it's a problem with my carbs.  

Anyone else had this problem?  Thanks as always!
'77 CB750K
'79 Yamaha SR 500
'97 Kawasaki KLR 650
seestheday
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Re: Throttle won't come back to idle

seestheday
Is there a problem with the spring?  It's what you say about it dropping if you close the throttle manually that makes me think this.  

With the bike off, if you disconnect the throttle cable completely does the throttle linkage snap back well if you just engage it with your finger?

I believe you should be able to check this by just taking the gas tank off.  Hopefully you won't need to remove your carbs to test it.
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals

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cdaiscool
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Re: Throttle won't come back to idle

cdaiscool
I agree in that it sounds like your spring is having some issues, or the cables are gummed up. But if it's drifting back to 3500 rpm after you twist the throttle, then I'm thinking/betting that your spring's loose. It's not holding the cable back in place, nor pulling it back.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
TOOLS1
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Re: Throttle won't come back to idle

TOOLS1
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In reply to this post by McMaleus
If the spring checks out OK then check, for vacuum leaks.
TOOLS
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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
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shinyribs
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Re: Throttle won't come back to idle

shinyribs
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I'd bet it is a vacuum leak. Spring or no,the throttle shouldn't creep around twist all by itself.
McMaleus
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Re: Throttle won't come back to idle

McMaleus
All the cables and springs looked to be  okay yesterday so I really think it's a vacuum leak.  More inspection on the way!  I'm dying to get on the road for the first time this spring.  The wait is killin me!

Thanks again guys.
'77 CB750K
'79 Yamaha SR 500
'97 Kawasaki KLR 650
cdaiscool
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Re: Throttle won't come back to idle

cdaiscool
How I find a vacuum leak: spray brake clean or carb cleaner around rubber hoses. When your idle jumps, and drops a bit when done spraying, you found your leak.
Turbos, Hondas, 4-bangers, what could go wrong?

Fuelly

Shiny: [...] Considering the weather you've had to put up with I'd say you get an Iron Butt award and a Frozen Nipple trophy to go along with it. First time I've ever posted the word nipple... it ends here.
McMaleus
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Re: Throttle won't come back to idle

McMaleus
In reply to this post by shinyribs
All the cables and springs looked to be  okay yesterday so I really think it's a vacuum leak.  More inspection on the way!  I'm dying to get on the road for the first time this spring.  The wait is killin me!

Thanks again guys.
'77 CB750K
'79 Yamaha SR 500
'97 Kawasaki KLR 650
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