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I have a performance problem. My bike runs very poor (missing) between 2800 and 4000 RPM.
More info:
1. 86 1200
2. Carbs rebuilt and adjusted to specs using mercury carb sticks.
3. New Plugs gapped to .040 (pulled plugs and they are very clean)
4. Very low restriction exhaust with addedbaffles.
5. Starts and runs good below 2800 RPM andOK above4000 RPM
6. The problem gets worse with load (going up hill or hard acceleration)

Thanks for any help.


FW
 

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Just a guess, but sounds like poor fuel pump pressure or a clogged fuel filter. The problem that you discribed is really a hard one to do online, it could also be running too lean, possible bad plug wire on one plug, or a weak coil. I would check the fuel filter first, than test the other items. It is also possible with the low restriction exhaust that you might need to rejet.:)

But anyway, Welcome to the best Goldwing Forum on the planet! Some of the gurus will have some great advise for you too, so good luck!:dude:

Gene:waving::11red::11red::11red::cooler:
 

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I would agree, worse with load or going uphill may be a fuel problem. However, I did have a cx500 with a missing type problem at speed and it turned out to be the pulse generator . But I sure would look for the easy things first.

may I ask? Why did you add baffles to the exahust?
 

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Welcome to the forum Fat_Wing.
You say the bike runs OK above 4000 rpm? If so, I would think the fuel delivery is OK.
Is the missing "hard" or does the enging bog down and putter?
Like GLester says, this could be tough without hearing it.
 

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rcmatt007 wrote:
I would agree, worse with load or going uphill may be a fuel problem. However, I did have a cx500 with a missing type problem at speed and it turned out to be the pulse generator . But I sure would look for the easy things first.

may I ask? Why did you add baffles to the exahust?

I put a low (no) restiction exhaust on it and did not increase the jets in the carbs. My experiance with old HD is this usually makes the low to mid range run poorly from running to lean. I addeed the baffles to add some back preassure and make the mixture a little richer.



Thanks

FW
 

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johnmac wrote:
Welcome to the forum Fat_Wing.
You say the bike runs OK above 4000 rpm? If so, I would think the fuel delivery is OK.
Is the missing "hard" or does the enging bog down and putter?
Like GLester says, this could be tough without hearing it.

Thanks

It is a hard miss. It is not as bad in first and second but I think that is because the rpm's go up so quick.

If I'm in 5th gear say gettingon the highway at about 55 mph (2800 rpm) and tringto get to 65 mph it will miss badly and will not cruise smoothly at 65 mph (3400 rpm)
 

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I would take a look at the electrical connections from the pulse generators (in the timing belt covers) to the coils. Unless, one of your carbs is starving for gas. Maybe, under light throttle and low rpm the bike runs OK, but one carb is running out of gas under high rpm and more load.
Just some thoughts. (guesses!)
 

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Did your problem start after the carb rebuild.

Is the problem wose at partial throttle openings.

You will have an accelerator pump drop extra fuel in when cracking the throttle.

How did the vacuum pistons look when you rebuilt the carbs ?

Plugs still look good ?

High RPM runs good usually eliminates fuel delivery except carbs. It also usually eliminates ignition, unless low RPM is bad then points at charging system.

Carbs have different circuits in them that operate at different throttle openings.

I guess I'd start with some easy checks, looking for vacuum leaks, use a carb cleaner spray at the joints and shaft openings, listen for idle change.

After that, I'd have to look into the carbs again.
 

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There is one more area. As a former auto mechanic, it was hard to believe how many times the air filter was over-looked. It could possibly cause the same symptom as a clogged fuel line/filter. Good Luck!
 

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Wendell wrote:
There is one more area. As a former auto mechanic, it was hard to believe how many times the air filter was over-looked. It could possibly cause the same symptom as a clogged fuel line/filter. Good Luck!
on my chain saw (I know a wing is not a chain saw) the thing really bogged under load... messed with everything on the intact side... turned out to be the exhaust screen was plugged up and it was an out-flow problem.
 

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Fat_Wing wrote:
I have a performance problem. My bike runs very poor (missing) between 2800 and 4000 RPM.
More info:
1. 86 1200
2. Carbs rebuilt and adjusted to specs using mercury carb sticks.
3. New Plugs gapped to .040 (pulled plugs and they are very clean)
4. Very low restriction exhaust with addedbaffles.
5. Starts and runs good below 2800 RPM andOK above4000 RPM
6. The problem gets worse with load (going up hill or hard acceleration)

FW, 2800-4000 RPM's covers a pretty broad range of carb circuits.

Probably the place to start is to flip the choke (enrichener) lever back on as the problem happens. If that helps or makes it run better then you probably have a carb circuit problem, low set carb floats,or low fuel flow to the carbs.

The early 1200's had a real lean carb jetting problem with a service bulletin issuedto change metering rods, slide springs, & pilot jets. Withyour added free flowing exhaust that would get even worse.

If you managed to set the float level lower than spec that alone could cause your problem as that is the RPM range a low float setting would most effect.

I guess if it were my 1200 with that problem I would start with the pilot jet needles set to about 4 turns out from seated to see if that alone would richen it enough to help. If that made it better but still not perfect I would add a small .024" washer under the slide needle to raise them a little & see if that helps more. I would also be sure I had set my carb floats to the highest side of the factory specs.

There is no accelerator pump or pumps in the 1200 carbs so that will have no effect.

With your problem getting worse when climbing a hill under load it could also point to a fuel flow problem. Probably the 3000-4000 RPM range under a load or throttlecrowd uses the most fuel flow, as you go over 4000 RPM's the load usually eases up & the fuel usage requirementcould go down somewhat. A good test of fuel flow is to run the bike in high gear at max speed. If it will pull about 110-115 MPH (sustained for a mile or so)on level ground the fuel flow is pretty good.

Twisty
 

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Fat_Wing wrote:
I have a performance problem.
Hey Fat_Wing :stumped: Maybe you should visit your doctor he might sort you out.:clapper:

Everytime i switch on my neighbours PC and connect to the net, i get so many emails about this stuff they call Viagra :whip: and im nearly 80yrs of age and single. :realshocked: :shakehead:

Anyway, A big Irish Welcome to the Best Goldwing Forum on the net. :weightlifter:

:leprechaun::18red::leprechaun:
 

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I don't believe the 1200s are particularly sensitive to exhaust system changes you might see what happens with the baffles out. I'd suggest trying the choke as Twisty said when the problem appears that's always a quick check to help separate the old ignition or carb conundrum. One other thing you might try is to reduce the plug gap down to .028 or so and see if it gets better or worse. The main thing right now is to figure out if it's fuel or spark.Does this problem occur if you try to cause it in 3rd gear? The advance in 4th and 5th is done by the ECU (I think on your bike) and that could have a play.
 

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Hi,

I have the exact same sounding problem on my new-to-me '77 GL1000 where the bike seems to be running more or less fine, but struggles in the mid-range revs. I'm also pulling my hair out trying to establish whether this is spark or fuel too!

See thread on NakedGoldWings.com here >>>
http://nakedgoldwings.com/forum/viewtopic.php?p=5241#5241

So far I've sprayed aerosol carb cleaner under the air filter, cleaned & repainted the air filter box, and run a bottle of STP fuel system cleaner thru the fuel tank. Next jobs are:

- new plugs gapped & fitted
- secondhand coils (£25) from a GL1100 with small mod to fit
- adjust timing (not advanced enough)
- adjust mixture (running too rich)
- new air cut-off valve & fuel filter from http://www.davidsilverspares.co.uk
- check cylinder compression
- check carb balancing with tool from http://www.carbtune.com

That's about £60 in new parts and some more money on tools that I can use again, and all should make a small difference. If I nail the one single biggest problem I'll be sure to let you know!
 

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Hi Hirsty and welcome. It sounds like carb problems on your bike, can't remember if it was the 76 0r 77 that was the worst for carb problems. I'd say you are just meddling around and avoiding pulling the carbs, which I think you will really have to do. I would want to be sure the insides were spotless before buying things like secondhand coils.
 

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Discussion Starter #17
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Well

I'm sure it is in the carbs now. I put a small washer under the needle to shim it up and the problem got a little better butnot much. I also road it with the choke ON a little and it got a little bit better.

I'm starting to second guess my float levels now. Can anyone tell me at what RPM range should be the power band for a GL1200? and what is the red line? I built my bike from scratch and it is all custom so I don't have an origal tach to tell me what the red line is.

Thanks

FW
 

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Isn't a .040 Spark Plug gap a little excessive? The GL1200 manual calls for .031 to .035 for gapping. Could this be part of the problem????
 

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Hey hirsty :leprechaun:A big welcome to the best Goldwing Forum on the net. :clapper:All your answers will be provided here so visit often. :weightlifter:

:jumper::18red::jumper:
 

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I pulled the carbs and reset the float level to 7.5 mm and all is well. She pulls hard now. In first it will almost pull the front tire and now in forth and fifth the miss is gone.



FW
 
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