Off idle hesitation 1500


Information and questions on GL1500 Goldwings (1988-2000)
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propasstoro
Posts: 14
Joined: Sun Jan 31, 2010 11:35 am
Location: United Kingdom
Motorcycle: 1992 GL1500

Off idle hesitation 1500

Postby propasstoro » Sun Dec 30, 2012 9:23 am



Hello Fella's I hope you all had a wondeful Christmas... :D

I am hoping someone can help with my Off Idle hesitation on my 1989 model year 1500 which has covered just 50,000 miles, for a couple of years or more this very slight hesitation has bugged me and it may have been there a lot longer if I am honest but I think I have adjusted my riding accordingly, I have recently done a few good runs through France and always I have been aware of this hesitation when entering a roundabout, just when I pick the revs up it stutters (Only slightly but I notice it) It is more un-nerving in the wet when fully loaded.
So this is what I have done so far:
1. fitted a new 4 degree trigger wheel and cam belts.
2. Removed the carbs, stripped them, Cleaned them very thoroughly, replaced all of the jets I could with a Sirus kit, fitting new float bowl valves, new needles, new slow jets .55 reset the float levels to 7.5mm, stripped the accelerator pump and cleaned it thoroughly, replaced all seals and gaskets, set the pilots jets up to 2 turns out (Initial setting), checked every vacuum hose and replaced any that required replacement, fitted a new sub air filter, fitted a new cruise filter, fitted a K+N air filter, fitted new plugs, checked compressions, polished the vacuum pistons so they slide very smoothly, checked the diaphrams, refitted the carbs and reset the pilot jets correctly as per the manual, balanced the carbs with guages and she idles and revs perfectly.
My issue is that if I pick the revs up slowly from idle through to high revs there is a spot between 1200 and 1500 rpm where the revs start to splutter but then the revs smooth out ok?
I still have the bike plastic work stripped off and I do not want to rebuild it any further as I dont feel I have sorted the problem due to the splutter???
The kit did have some .58 slow jets in it but I was not sure if they would have helped? what do you think?
I have a copy of the Honda bulletin for the 88, 1500's and that states that it will need an ignition cntrol unit and a carburretor control unit? do you think I am going to need these?
Does anyone have any thoughts on this or on anything I could have missed or anything else I should be looking at?

I would appreciate any help or advice tou could give.

I was a fully qualified Auto mechanic and elecrician when I was a boy (Now 58) so I sort of know roughly what I am doing and I learn quickly???

Thanks for any help you can give..

Jon



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RBGERSON
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Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: Off idle hesitation 1500

Postby RBGERSON » Sun Dec 30, 2012 10:04 am

Sounds like you have touched everything that effects that issue..the trigger being the main fix..I'd recheck the cv slides and the cam wheel marks/settings. You might try squirting some propane or starter fluid around the vacuum tubes if the engine rpms jump..you have an air leak??? Also the accelerator pump/nossle do you see a nice squirt of flue when you crank the throttle
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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propasstoro
Posts: 14
Joined: Sun Jan 31, 2010 11:35 am
Location: United Kingdom
Motorcycle: 1992 GL1500

Re: Off idle hesitation 1500

Postby propasstoro » Mon Dec 31, 2012 6:24 am

Hi RBGERSON,
Thanks for your thoughts on this, so far I have replaced and examined every single vacuum hose throughout the system, have checked the timing and considered refitting the original trigger wheel etc, I am now considering removing the carbs again, replacing the slow jets for .58 jets (which I would hope will richen the mixture on the changeover point), replacing the accelerator pump diaphram and also cv slides (although these slide very smoothly) I will then reset the pilots and hope???
I am still a little concerned that the CCU box could be the problem? or even the ICU unit?? what do you think???
Also I dont know if either of these electronic boxes from a later bike are compatible???
I dont know what else I can do after these fixes???
Thanks
Jon

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RBGERSON
Posts: 2625
Joined: Tue Mar 09, 2010 7:57 am
Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: Off idle hesitation 1500

Postby RBGERSON » Mon Dec 31, 2012 8:11 am

I think the electronic stuff works or it doesn't..at all. accelerator pump or sticky CV's is my guess. You should see a nice squirt of gas when you crank the throttle..with the air box off so you can see in there..

The weak spots on the tubes is where they bend..that's the most common place for a crack to develop and hard to see or feel.
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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virgilmobile
Posts: 7660
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Off idle hesitation 1500

Postby virgilmobile » Mon Dec 31, 2012 1:29 pm

If you can hold the rpm in the affected range...add just a little "choke" at that time.
If it smooths out you have a slight fuel starvation.
I cured this in my 1200 by lifting the needle on the slide.I used a washer(about 0.13") to raise the metering needle slightly to increase the fuel mix.

Wait...cancel that.it's for mid range..1500-2500 rpm.
Yours is slow speed.1000-1800 rpm.
Increase the slow speed jet size just a touch.I think I went from the stock 55 to a 60.

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virgilmobile
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Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Off idle hesitation 1500

Postby virgilmobile » Mon Dec 31, 2012 1:57 pm

Oh and by the way,mine is a 88.original ECU and ccm module.I modified the accelerator pump and replaced the hardened diaphragm to improve the initial squirt as soon as I twist the throttle.

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propasstoro
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Location: United Kingdom
Motorcycle: 1992 GL1500

Re: Off idle hesitation 1500

Postby propasstoro » Mon Dec 31, 2012 2:18 pm

Hi Fella's
This fix may be what I think it needs too, I have a pair of .58 jets which I think I will fit and I will purchase a new pump diaphram and fit that too, I am also going to give the carbs a good soaking in cleaning fluid for a couple of weeks to really get into it, I will then start the set up procedure all over again and hope... :idea: 8-)

I will keep the forum posted when I have the old girl running again...

Thanks

Jon :D

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gipsy42
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Motorcycle: 1993 GL1500 SE
1978 GL1000
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Re: Off idle hesitation 1500

Postby gipsy42 » Wed Jan 02, 2013 8:05 am

Hi Jon:
Before you’ll go any further, may I suggest take a look bellow the carbs, under the rubber covering the intake manifold, at the small hose ( about 6mm in diameter) that’s bypassing the right and left intakes, if it’s punctured it will cause a vacuum loss with the results of your RPM idle hesitation. I had the same trouble on my 93 SE.
Hope this may help you.
Kind regards, Mario
Mario
aka Gipsy42
And still riding...
I just regrets the things I haven't done.

http://www.surfcam.com.ar
http://www.cre-angeles.org.ar

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propasstoro
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Location: United Kingdom
Motorcycle: 1992 GL1500

Re: Off idle hesitation 1500

Postby propasstoro » Thu Jan 03, 2013 5:21 pm

Hi Mario,

Thank you for that information I will look and look again, I thought I had examined every hose but maybe, just maybe I have missed one??? :roll:

I will set about the carbs again this weekend.

Thanks

Jon

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robb
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Location: Lexington, North Carolina
Motorcycle: 1989 Honda GL1500 Aspencade

Re: Off idle hesitation 1500

Postby robb » Thu Jan 03, 2013 7:54 pm

What I found on my 89 was that the 90 degree tubes on heads were partially blocked. Too little vacumn for need, once cleared all hesitation gone.

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gipsy42
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1978 GL1000
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Re: Off idle hesitation 1500

Postby gipsy42 » Fri Jan 04, 2013 11:35 am

Hi Jon:

Just in case you need it, I scanned the manual with the tubes in question, they're hidden below the rubber.
mario
Attachments
Mario
aka Gipsy42
And still riding...
I just regrets the things I haven't done.

http://www.surfcam.com.ar
http://www.cre-angeles.org.ar

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propasstoro
Posts: 14
Joined: Sun Jan 31, 2010 11:35 am
Location: United Kingdom
Motorcycle: 1992 GL1500

Re: Off idle hesitation 1500

Postby propasstoro » Fri Jan 04, 2013 11:54 am

Thanks Mario,

I really hope you are right as this problem has been going on long enough and has got even worse in my head as the days go on, I think I also have done so many things that I am not even sure what I have done so its always good to get a second opinion :)

I will let you know what I find.....

Jon

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propasstoro
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Joined: Sun Jan 31, 2010 11:35 am
Location: United Kingdom
Motorcycle: 1992 GL1500

Re: Off idle hesitation 1500

Postby propasstoro » Mon Jan 14, 2013 11:01 am

:D Hi Fella's

I think I may have fixed it :shock: I pulled the carbs off for the 4th time and checked everything and I mean everything, I have replaced any suspect hoses but I dont think it was these, I have stripped the carbs and replaced the Pilot jets, resetting them to 2 and a half turns out (Initial setting), I have replaced the slow jets for 60s and the mains for 158s I have also fitted a new Accelerater pump diaphram and adjusted the arm to ensure there is no slack in the pump starting to pump, I have stripped the pistons and cleaned and polished the inside and outsides so they move very smoothly (they moved smoothly before) there was also a "T" peice that looked suspect on the vacuum side which I have replaced.

I refiited the carbs on Saturday and started the old girl up and as soon as she struck up I knew it was cured, I still have to reset the mixtures and balace the carbs but there is no flat spot/hesitation anywhere in the rev range and she ticks over as smooth as you like..

Man Oh Man, that has been a tricky problem to sort out and I still dont know which bit sorted it out :?: All I know is that I am confident it is now sorted..
I will post another note when I have road tested her.

One thing I think I have learned from this is if you do have a hesitation get rid of the bike straight away.....

Just kidding ;) when you do strip it make sure you go through every small detail and I mean EVERY small detail, Oh and one further thing do not attempt this type of job without a digital camera, take loads of pictures all of the time, you think you will remember but let me tell you it all looks the same in there and the workshop manual diagrams are not pictures they are line drawings...

And always keep calm and smile otherwise you will break something.........

Safe Riding everyone and thanks for your help 8-) :lol:

Jon




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