84 gl1200 carb problem?


Information and questions on GL1200 Goldwings (1984-1987)
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virgilmobile
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84 GL 1200 I

84 gl1200 carb problem?

Postby virgilmobile » Mon Nov 14, 2011 1:27 pm



Sounds like it's lean,stumbling from 2000-3000 rpm.Add a little "choke" or fuel enrichening and it smooths out.
Popped the carbs off and gutted them.Checked the float level,inspected all the jets,ports,air passages,air valves,etc,etc.Everything is spot on and clean.No contamination.
I can't find any reason for the lack of fuel in that rpm range.Even the enrichening valve is ported from the idle jet as are the 4 midrange holes.So it's not a idle jet problem.
Some reading mentioned adding a spacer under the main jet needle,other increase the jet size,and some say a pulse coil gap problem.
This idles great and pulls smooth from 1000-1800 then again from 3000 up.
When at 2500 rpm,it sounds and feels like a twin.Add a little choke and it sounds and feels like it's firing on all 4.(not a ignition problem)?.
I checked the cutoff valve and the reed valves(working,no leaks).All the hoses are clean and pliable.
Original hoses however.
I'm stumped on this one.
I can't point my nobby finger at a single defect.
Help??? :)



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tricky
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Re: 84 gl1200 carb problem?

Postby tricky » Tue Nov 15, 2011 9:50 am

how about checking the fuel pump and or filter, especially the filter.
unless of course you already have.
I know some of the fuel filters have been breaking down recently

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virgilmobile
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83 GL1100 I
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84 GL 1200 I

Re: 84 gl1200 carb problem?

Postby virgilmobile » Tue Nov 15, 2011 11:42 am

Been there,fixed all that(even the noisy ticking pump).The bike pulls fine above 3000 rpm,so not a fuel flow problem.
I've been reading that the 84 had a factory mod for this problem.
I'm researching adding a 3mm shim to lift the needle up and changing from a #35 pilot jet to a # 36. :?:

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virgilmobile
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83 GL1100 I
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84 GL 1200 I

Re: 84 gl1200 carb problem?

Postby virgilmobile » Tue Nov 15, 2011 4:10 pm

Here's the most common info across the board about the 1200 carb problem.
I got the stuff to try it....http://www.goldwingfacts.com/forums/forum1/50239-1.html.

I'll know in a day or so and I'll post my pix of the work.

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virgilmobile
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82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 84 gl1200 carb problem?

Postby virgilmobile » Wed Nov 16, 2011 3:12 pm

Update so far,mosquitoes are eating me alive,and I found some problems in the carbs.
2 pilot jets near plugged
1 spring on a needle valve seized
Out of 4 idle mixture screws,not any one were set the same,eg.1and1/2 to 3 and1/4 turns out.
All the slides were scuffed up and MAY have been dragging.
Other than replacing the pilot "O" rings,the only mod is I added a shim under the main needle metering rod.
Here's the pix.
Hope to finish tonight and sync tomorrow.Gonna be 78 this weekend :)
scuffed slide bore
scuffed slide bore
Attachments
cleaned all the pilot jets
cleaned all the pilot jets
farm fresh slides
farm fresh slides
polished the slides with 2000 grit
polished the slides with 2000 grit
added a shim to let in more gas
added a shim to let in more gas
drilled the pilot cap
drilled the pilot cap
heat needed to remove the cap
heat needed to remove the cap
popped right off
popped right off
polished the bore with 2000 grit
polished the bore with 2000 grit

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seabee_
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1975 Honda CB360T

Re: 84 gl1200 carb problem?

Postby seabee_ » Thu Nov 17, 2011 10:09 pm

I was going to suggest the mixture adjustments but I see you already found that. I was also going to recommend synching the carbs. I had a KZ400 that had the same symptoms and rebuilt the carbs thinking that would fix it. In the end found the idle mixture screws way out on adjustment and carbs way out of synch even after bench synching with feeler guages. Built a homemade manometer and synched the carbs. Man, what a difference that made.
By the way, nice pics on the progress.
Paul
CE1 Navy Seabees/RET
1981 to 2002
ASE Mechanic

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virgilmobile
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82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 84 gl1200 carb problem?

Postby virgilmobile » Fri Nov 18, 2011 9:18 am

Thanks for the info.Here's the final results...
Note:prior to repairs,,at 2500 rpm in the shop,if I add a little "choke"the rpm would climb to just over 3000 rpm.Now if I add a little choke the rpm drops.This indicates the fuel mix is about right.
1.found 2 idle jets near plugged.I could see through them,but only barely.
2.the slide bore and slides were scuffed,not really bad,so I polished them anyways.After I put them back,I used a vacuum cleaner hose to watch the movement of each one,simulating the engine demand and slide response.
3.I found the idle screws were set from 1/2 to 3 turns out.I replaced the "O" rings and set them to 3-1/2
4.I added a 0.033 washer under the main needle to lift it and hopefully get a little more overall fuel delivery.Just trying to get rid of the lean condition.
5.I replaced all the rubber hoses and "O" rings on the down tubes.
6.Mechanically set the throttle and re-assembled the bike.
7.Synced the carbs at 700 rpm.
8.Adjusted the idle jets at 900 rpm > I turned them IN till I saw and heard a idle drop and then turned them 1 full turn back out.Each one ended up being 4 turns from the bottom.
9.Re-synced the carbs again to the nats ass.

I held the throttle at 2000 rpm and applied a little choke and the rpm dropped.Just what I'm looking for :D
It was 37 degrees when I finished,so a test run this weekend,79 degrees. :)
The throttle response is much snappier and I have a hard time trying to hold it at 2500 rpm.It just seems to go from a idle to 5 grand with just a little tweak on the throttle. :o




new82
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Re: 84 gl1200 carb problem?

Postby new82 » Thu Dec 01, 2011 8:45 pm

virgilmobile wrote:Update so far,mosquitoes are eating me alive,and I found some problems in the carbs.
2 pilot jets near plugged
1 spring on a needle valve seized
Out of 4 idle mixture screws,not any one were set the same,eg.1and1/2 to 3 and1/4 turns out.
All the slides were scuffed up and MAY have been dragging.
Other than replacing the pilot "O" rings,the only mod is I added a shim under the main needle metering rod.
Here's the pix.
Hope to finish tonight and sync tomorrow.Gonna be 78 this weekend :)


Hi Virgil - Are you really 78?? you looked a LOT younger when I met you. congrats on a life well lived.

I'm still playing with getting my carbs syncéd (still rough from idle to about 2200, & lots of primary chain rattle) but i was wonderring if the 1200 needle shims would help the 1100. seems to me the ethanol problem would be same for 1100s & even 1000s

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virgilmobile
Posts: 7659
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: 84 gl1200 carb problem?

Postby virgilmobile » Thu Dec 01, 2011 10:40 pm

Well sometimes I FEEL 78,but I'm not quite there yet.I do qualify for the senior discount at Goodwill tho.
I really don't think that lifting the needles in the 1100 or 1000 may help much.After I polisheed the carbs in the 1100 really,really good and adjusted the snot out of them the bike will pull off at a idle(900 rpm) ,Idle down the road and twist the throttle half way and it just pulls smooth through 7 grand.
Lifting the needle .033" on the 1200 provided just a bit more fuel to help with a little lean condition.I really think the sticking slides and mis-adjusted idle screws had a big part in it.That is what cleared up the 2000-3000 rpm lag problem.




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