Take off problems


Information and questions on GL1000 Goldwings (1975-1979)
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whiteclad57
Posts: 27
Joined: Wed Apr 29, 2020 1:48 am
Location: Sisters, Oregon
Motorcycle: 1978 GL1000 Goldwing
1981 GL500 Silverwing

Take off problems

Post by whiteclad57 »



Just rebuilt the clutch and put my carb set back on the bike only to notice it's having some of the same problems it had before the rebuild. The bike has basically no torque when below 3000rpm.
It idles fine at 1000rpm when at operating temp and can even idle cool well at 800rpm.
Carbs are synced, timing belts are new with new rollers.
Once it gets above 5mph it has basically no problem and it feels great from 4000rpm and up. However, getting it going from a stop requires rolling the throttle basically up to 3000-4000rpm and very carefully fluttering the throttle less the rpm drop rapidly and stall out.
At this point basically the only thing I haven't messed with or tested on this bike that could impact this is the ignition timing, but wouldn't that affect the whole range?
Both coils/resistor lines are within 900ohms of spec, new spark plugs, carb was rebuilt properly using Randakk's kit.

The only other thing I can think of is that the previous owner replaced the jetting with the wrong ones when he rebuilt it using an offbrand kit that has unmarked jets. The PO's other "restoration" work basically all had to be replaced and redone so I wouldn't put this past him as well.

Ignition first? Or new jets to be sure? Anything else it could be?

It did have this problem before the rebuild as well, although to be clear the carbs had several other issues which I had to address as well such as an out of setting float bowel, degraded o-rings, stripped screws and heavy use of gasket sealant.
I'm getting to the point I'm just considering a Pic 3 single carb conversion so I can just be done with it and stop chasing the PO's numerous careless mistakes.
Hell I've already sunk $400 into trying to get the OEM carbs working via two rebuild kits from randakk, and a separate set of 769A carbs from eBay that looked great but were seized internally and filled with corrosion and varnish.

The current set of carbs still has stripped float bowel screws and air filter chamber screws so I'm loathe to sink another $120 to replace the (most likely) saber-cycle jetting and idle mix screws with keyster/oem outside of maybe salvaging what I can from the other wrecked carb set.

If I do go the single carb route anyone have any suggestions for the best carb/manifold set? After two years I honestly just want to get this bike running properly, and I'm tired of getting burned on ordering used parts.


joecoolsuncle
Posts: 562
Joined: Sun Sep 26, 2021 6:10 am
Location: oxford, ar
Motorcycle: 1984 gl1200a

Re: Take off problems

Post by joecoolsuncle »

partially engage choke. if that helps, then tear carbs back down.also look for vacuum leak. if choke doesnt help then i would look at point gap or timing. checked cam timing to make sure not a tooth off?
whiteclad57
Posts: 27
Joined: Wed Apr 29, 2020 1:48 am
Location: Sisters, Oregon
Motorcycle: 1978 GL1000 Goldwing
1981 GL500 Silverwing

Re: Take off problems

Post by whiteclad57 »

Timing belts are correct, checked them just to be sure right before I put the engine back in the bike last week.
I'm guessing to check the choke I should get the bike up to running temp. pull the choke halfway and then lower curb idle and see if performance is improved?
The issues on this bike are throwing me for a loop.
Prior to the rebuild it was running rich and floats were sticking on left bank, aircutoff valve was missing its inner o-ring
post rebuild I gained ~500rpm to the curb idle and the floats no longer seem to stick but now it has all the signs of running lean off-idle except temps are actually lower than before.
I'm getting a sucking sound from the right bank as well that's only audible at low rpm's (sub 1200) so I think there may be a vacuum leak in the air cutoff system although I tested the valve itself and that's fine. Is there any way to test that the o-rings it's seated on are sealed correctly?
joecoolsuncle
Posts: 562
Joined: Sun Sep 26, 2021 6:10 am
Location: oxford, ar
Motorcycle: 1984 gl1200a

Re: Take off problems

Post by joecoolsuncle »

if you hear a sucking sound that is distinct, i would cut to the chase and identify, correct, and ride! look for the vac leak. double check the vacuum hoses from the manifolds and ALL orings.
maybe someone else can offer info more specific to that exact model.
whiteclad57
Posts: 27
Joined: Wed Apr 29, 2020 1:48 am
Location: Sisters, Oregon
Motorcycle: 1978 GL1000 Goldwing
1981 GL500 Silverwing

Re: Take off problems

Post by whiteclad57 »

if you hear a sucking sound that is distinct, i would cut to the chase and identify, correct, and ride!
Fair enough, it had this problem before the rebuild when it didn't make said noise but it is best to fix the problems you're aware of. Just not looking forward to taking these carbs off multiple times, tis a pain getting those throttle cables back in

Rear tires off the bike right now as it's somehow reached it's runout limit despite not having more than 28k on it. Will give me time to take the carbs off again and vacuum test/check float seats.
joecoolsuncle
Posts: 562
Joined: Sun Sep 26, 2021 6:10 am
Location: oxford, ar
Motorcycle: 1984 gl1200a

Re: Take off problems

Post by joecoolsuncle »

you will become very familiar with those carbs by the time you get everything straightened out! lol
peace
whiteclad57
Posts: 27
Joined: Wed Apr 29, 2020 1:48 am
Location: Sisters, Oregon
Motorcycle: 1978 GL1000 Goldwing
1981 GL500 Silverwing

Re: Take off problems

Post by whiteclad57 »

Well, I took the carbs off, vacuum tested them, checked the butterfly sync and the standing float levels. Everything checked out perfect.
However, I think I may have a lead towards fixing the problem, previous owner lost the airbox/plenum gasket and used silicone to seal it.
My mechanic never brought this up or mentioned it when I went to him to have him fix the ignition advancer and repair the carbs.
The airbox has thus been loosely set over ragged silicone this entire time with no solid seal. In addition, he replaced the air filter with a K&N gauze type... and never oiled it.
This bike has been through several hands and its clear none of them knew what they were doing.
Got a new gasket and paper type air filter coming, I doubt this will fix everything, but I will be surprised if it doesn't address the sucking sound (missing gasket) and some of the lean issues when rolling off idle.

EDIT: Is the fuel pump meant to have gas in the lower pump tachometer section? I didn't question it when the new one I installed last some down there as the manual doesn't call for lubing the tachometer splines, so I had assumed it was using the gasoline to do that job. However now I want to make sure my pump isn't defective and just failed early.
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Maz
Posts: 828
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: Take off problems

Post by Maz »

whiteclad57 wrote: Fri May 06, 2022 7:29 pm

EDIT: Is the fuel pump meant to have gas in the lower pump tachometer section? I didn't question it when the new one I installed last some down there as the manual doesn't call for lubing the tachometer splines, so I had assumed it was using the gasoline to do that job. However now I want to make sure my pump isn't defective and just failed early.
No, there should not be fuel in the lower section. If there is, it should drip from the weep hole, but it will find its way into the crankcase and dilute the oil.
Maz
Ironically, Common Sense is the LEAST common of all senses!
whiteclad57
Posts: 27
Joined: Wed Apr 29, 2020 1:48 am
Location: Sisters, Oregon
Motorcycle: 1978 GL1000 Goldwing
1981 GL500 Silverwing

Re: Take off problems

Post by whiteclad57 »

Well, that's concerning. I checked the diaphragm and didn't see any obvious signs of tearing; the pump only has like 120miles on it. To be fair it is not much fuel, less than half an ounce at most. I have a replacement diaphragm seal for it, will have to tap the diaphragm post to make it serviceable and replace it when I get a chance later on. The gas never reached the weephole, is it possible it's coming from the crankcase through a small leak instead?
User avatar
Maz
Posts: 828
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: Take off problems

Post by Maz »

whiteclad57 wrote: Sat May 07, 2022 6:00 pm Well, that's concerning. I checked the diaphragm and didn't see any obvious signs of tearing; the pump only has like 120miles on it. To be fair it is not much fuel, less than half an ounce at most. I have a replacement diaphragm seal for it, will have to tap the diaphragm post to make it serviceable and replace it when I get a chance later on. The gas never reached the weephole, is it possible it's coming from the crankcase through a small leak instead?
There shouldn't be any fuel in that area at all. The crankcase should only have oil in it, in that area.
Maz


Ironically, Common Sense is the LEAST common of all senses!
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