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Technical Help Forum
Started by Hairybears at 03-02-2010 11:05 AM. Topic has 19 replies.
  
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 03-02-2010, 11:05 AM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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My GL has started to rev high at idle????
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Hello all and thanks for reading my first post in this forum.
I've recently removed the fual tank from my 81 GL for a clean.....now at idle its doing 4k RPM and i havnt a clue why. All i've done is removed the tank? I've looked at the choke, it doesnt look like it sticks and the throttle cables seem to return to the relaxed position.
Has anyone got any pictures of a set of carbs set up?
The only thing that I can say is i'm unsure if the vacuum hose is on the right position on the fuel tap...any advice more than welcome.
Cheers
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-02-2010, 12:42 PM
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rickbert
 
Joined on 01-05-2009
Missouri....60 mis East of KC
Posts 1,384
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Re: My GL has started to rev high at idle????
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If it idled fine before you took the tank off then I'm baffled too ! Or DID it idle and run fine before, full power etc ??
1982 CX500C...22K miles...owned since 10/08
My age: 45
Bike's name: "Long Cool Woman in a Black Dress"
If you need to contact me personally send an email, I never get my pm's for some reason.
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03-02-2010, 12:53 PM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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Re: My GL has started to rev high at idle????
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Thanks for the reply (and the Petcock issue). Prior to removing the tank it was fine, idled good (when warm) and smooth all through the rev range. I'm scratching a very sore head at the mement. Out od interest, do you know what the black plastic knob is for on the bottom of the carbs?
I did notice today that when I took the tank off that the fuel cock poured of fuel, even though there was no vacuum hose attached......
Apologies for the basic ?'s but as yet I have no literature at all for the bike....
Your help is appreciated.
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-02-2010, 12:53 PM
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spanish bandit
Joined on 02-12-2009
southern spain
Posts 5,010
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Re: My GL has started to rev high at idle????
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hi and welcome.please read the advice wmw gave you in you other post.
when you cleaned your tank you might have cleaned the petcock as well,allowing a better supply of fuel to the carbs.do you run with an inline filter
when i feel the need,i do it,llego,ve 60,s
-----------------------------
2008.1982 honda gli silverwing [uk model ]
2010.1981 honda gli silverwing [uk model ]
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03-02-2010, 12:59 PM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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Re: My GL has started to rev high at idle????
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Hi there
There's no inline filter and with regard to the fuel tank I didn't actually clean it, i just removed it to clean the frame of the bike so.....I'm stumped!
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-02-2010, 1:00 PM
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TheCrusher1234
Joined on 01-24-2010
Gilbert,AZ
Posts 58
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Re: My GL has started to rev high at idle????
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did you check for a vacuum leak? mine had a really high idle and after some checking i realized one of the bolts for the intake runner was missing and causing a leak. i bolted it down and it idled fine til other stupid decisions has it bricked again.
1981 GL500 Silver Wing
rigid conversion / 79 cx tank / rat bike
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03-02-2010, 1:03 PM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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Re: My GL has started to rev high at idle????
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No, I didn't however I certainly will now.....thanks
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-02-2010, 2:18 PM
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rickbert
Joined on 01-05-2009
Missouri....60 mis East of KC
Posts 1,384
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Re: My GL has started to rev high at idle????
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Your question : What is that black plastic knob on the bottom of the carbs ?
That's your idle adjust screw....as Bandit said maybe you dislodged some crap and now more gas is flowing hence the higher idle....it's possible.
So the next thing to try would probably be to get it running and turn that black knob so that it idles at 1100 rpm and just see HOW the bike runs from there....if it's ok then it's OK !
Can do no harm and it may just be ok.
1982 CX500C...22K miles...owned since 10/08
My age: 45
Bike's name: "Long Cool Woman in a Black Dress"
If you need to contact me personally send an email, I never get my pm's for some reason.
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03-02-2010, 3:32 PM
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SiriusBlackOp
Joined on 06-15-2009
Hudson, WI
Posts 445
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Re: My GL has started to rev high at idle????
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I can't say for certain what this is, but I can tell you that my bike last summer (I got mine from the previous owner who let it sit for 8 years so I’ve been bringing it back) was doing the same thing (idling at 4k) and after much work it turned out to be that the Carbs were full of all kinds of junk. I purchased a full rebuild kit, cleaned, rebuilt and re-synced the carbs and then the problem was solved.
With that said, my thought is that rickbert and bandit are right that you may have loosened some junk up, but without a fuel filter the junk went into the carbs. So, If nothing from above works, then I would first try some carb cleaner, then maybe if still not fixed try pulling the fuel bowls and make sure the jets are all clear using a welding tip cleaner. When I cleaned mine, half of the jets had some big chunks lodged in them.
This is the kind of scare that makes you go out and buy a fuel filter right now. LOL!
Good Luck! You'll get it going.
1981 Honda GL500
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03-02-2010, 4:40 PM
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Harold
Joined on 12-28-2006
Beside Washademoak Lake, N.B. Canada
Posts 851
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Re: My GL has started to rev high at idle????
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If you do not have the vacuum hose connected correctly, you may have an air leak causing the engine to run lean which can cause a fast idle. See the thread here for a diagram on vacuum hose routing.
If this is the problem it may mean that your vacuum petcock is not operating properly since the carb is getting gas. You can test the petcock, with the bike not running, turn the petcock to the off position and remove the gas line from it, hold a cup or something similar under the outlet to catch the gas and then turn the petcock to the on position(or reserve if the tank is low on fuel) , if gas flows the vacuum petcock is not operating properly.
I do not think that too much gas would cause a fast idle condition. 
"People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs."
1978 CX500
1980 CX500 Custom
1981 CX500 Custom
1982 GL500 Silverwing
1975 XL-100
http://www.myspace.com/downwiththebutterfly
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03-03-2010, 7:35 AM
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Abes_CW
Joined on 04-17-2007
saskatoon
Posts 3,037
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Re: My GL has started to rev high at idle????
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I'm with Harold on this. If the petcock pours fuel without vacuum, I'd block off the vacuum line coming to the carbs and see if that helps.
I don't think it would be an idle screw issue at all, this is an air/vacuum leak.
1983 GL650i
Had 4 CX/GL's at one point this year, down to one, next spring is another adventure!
age 38 (29 plus tax)
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03-03-2010, 10:08 AM
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Panther
Joined on 05-09-2006
Las Vegas, NV
Posts 1,264
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Re: My GL has started to rev high at idle????
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Also possible that the vacuum diaphragm on the petcock is leaking some fuel into the intake while the bike is running.
When they fail it can dump from just a bit of fuel to so much that it floods the cylinder. just depends on how bad a leak it is,
Peace & Light
>^..^<
..........
'83 GL650swi "My Little Grey Lady"
'82 GL500swi parts bike
'78 DT175
'86 LS650 Milady's bike
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03-03-2010, 10:16 AM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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Re: My GL has started to rev high at idle????
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All,
Thanks so much for this info...I feel like a complete novice.
I can confirm the petcock is not working as it was, i took the tank off the bike, turned the tap to the on position and fuel gushed out.....that didn't happen before. I then started the bike without the tank fitted and the bike ran the same.....fast at about 3500 revs.
The hotter the bike gets the faster the reving becomes....I supose its due to the engine being more efficient.....
I'll try to block the vacuum pipe at the carb at the weekend...see what that does!
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-07-2010, 4:14 PM
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Sidecar Bob
Joined on 03-02-2006
Kawartha Lakes, Ontario
Posts 1,901
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Re: My GL has started to rev high at idle????
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I had a similar symptom a couple of years ago. It turned out that the boot over the accelerator pump rod had a tear and the rod had corroded into the hole it passes through, preventing the throttle mechanism from returning to the idle stop.
Mr. Honda ('83 GL1000/Dnepr) summer
The Famous Eccles ('84 GX650EI/Velorex700) winter
WHY I HAVEN"T BEEN AROUND MUCH LATELY
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03-08-2010, 6:59 PM
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need4steed
Joined on 11-06-2008
Joliet IL
Posts 659
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Re: My GL has started to rev high at idle????
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My Gl500 did the same thing. turned out it was the intake boot. the rubber was cracked and letting in too much air. put some electrical tape over it and it ran like a dream. take the intakes off and do a visual check on the inside. Hope that helps
What dont kill you makes you more strong...metallica
1980 CX500 (sold)
1982 GL500 (cafe) AKA black bomber (473 Miles since finished build)
1980 xs850 yamaha (sold)
1979 CX500 (Track Bike)
72 cl350 (cafe project #2) AKA Ol Goat
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03-08-2010, 7:31 PM
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jcmcc
Joined on 07-21-2009
Madison, WI
Posts 36
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Re: My GL has started to rev high at idle????
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<BLOCKQUOTE><table width="85%"><tr><td class="txt4"><img src="/cs/Themes/default/images/icon-quote.gif"> <strong>need4steed wrote:</strong></td></tr><tr><td class="quoteTable"><table width="100%"><tr><td width="100%" valign="top" class="txt4">My Gl500 did the same thing. turned out it was the intake boot. the rubber was cracked and letting in too much air. put some electrical tape over it and it ran like a dream. take the intakes off and do a visual check on the inside. Hope that helps</td></tr></table></td></tr></table></BLOCKQUOTE>
+1 on this you can test for leaks by spraying parts cleaner around the boots.
1980 CX500C
24,500 miles and counting ;)
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03-08-2010, 9:11 PM
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LRCXed
Joined on 05-15-2008
Sacramento, California
Posts 1,670
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Re: My GL has started to rev high at idle????
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Check the throttle cables to be sure you didn't pull them out and they got hung up holding the throttle open.
Also check that the cables are sitting properly so they are not tight and pulling it open.
Depending on how much cleaning you did the choke and or throttle cable could be causing your issue.
Does the idle speed change when you unscrew the black knob idle speed adjuster? If not I would say you have a cable bind.
In my opinion dislodged fuel debris getting in the jets and fuel system won't cause higher idle speeds. It would lower it or cause flat spots in the rpm range or keep it from running at all.
If your going to do something, do it right, don't do it half as@*d.
78 CX500 Std, 79 CX500 project, 80 CX500C, 83 GL650I
http://globalcxglvtwins.hostingdelivered.com/
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03-22-2010, 12:41 PM
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Hairybears
Joined on 03-02-2010
Somerset, UK
Posts 8
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Re: My GL has started to rev high at idle????
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Thanks to all who offered advice, after a while I found the problem....read on if your curious....
After doing all the basic checks I done most of the recommendations you guys suggested..... all failed so I went back to basics. I took the tank off and observed the choke, it seemed to work normally however what I didnt realise whas that the choke is double acting in that it moves the butterfly valves on the first part then it pushes another lever which advances the idle, it was this lever which was stuck it the advanced position. A little carb cleaner sorted it out...
Many thanks for all the advice.
There are only 10 types of people in the world, those who understand binary...and those who dont!---------------------------------------------------------------------------------------------
'81 GL 500, As it left the factory! Almost.
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03-22-2010, 1:23 PM
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Harold
Joined on 12-28-2006
Beside Washademoak Lake, N.B. Canada
Posts 851
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Re: My GL has started to rev high at idle????
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Glad to hear you got it fixed, and thanks for posting what the problem was, it may help someone else in the future.
"People are more violently opposed to fur than leather because it's safer to harass rich women than biker gangs."
1978 CX500
1980 CX500 Custom
1981 CX500 Custom
1982 GL500 Silverwing
1975 XL-100
http://www.myspace.com/downwiththebutterfly
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Honda CX500 & G... » CX500 GL500 Tra... » Technical Help ... » My GL has started to rev high at idle????
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