86 gl1200 can't get up to 5000 rpm


Information and questions on GL1200 Goldwings (1984-1987)
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greenmechine
Posts: 4
Joined: Mon Sep 15, 2014 3:14 am
Location: tampa,fl
Motorcycle: 1986 gl1200 a

86 gl1200 can't get up to 5000 rpm

Postby greenmechine » Mon Sep 15, 2014 4:11 am



hello folk , need help with my 1986 gl1200 . at the 2nd , 3 rd and 4 th gear , i couldn't bring the bike up to the higher rpm . the bike holding back won't let rpm up .if i keep put some gas it will going up but holding of 3 to 5 sec.i did clean the carburetor ,changed fuel filter . vacuum line leak ? or fuel pump? please help :?



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HawkeyeGL1200
Posts: 918
Joined: Sat Jul 05, 2014 11:53 am
Location: Courtland, Va.
Motorcycle: 1984 GL1200 Interstate
1981 GL1100 Interstate

Re: 86 gl1200 can't get up to 5000 rpm

Postby HawkeyeGL1200 » Mon Sep 15, 2014 7:00 am

It does sound as though your fuel system is giving you trouble. Since you've already changed the filter, I would suggest checking the fuel tank cap to make sure it isn't blocked, creating a vacuum condition inside the tank. That would make the job of the fuel pump harder and can account for the poor performance.

Have your carburetors been balanced since you have owned the bike? It may not matter to upper RPM performance, but starting from a known place and moving forward is a good thing. The next thing I'd do is get a 18"-24" long piece of fuel line and put it on the outlet side of the fuel pump. Run it into a gas can, and turn the key switch on the bike to "on" position to see if the fuel pump actually moves any fuel. The flow rate isn't really high on the pump. (I'll have to look it up) So don't expects LOTS of gas, but it should move fuel.

You can also try bypassing the pump with a full tank of fuel and see if the bike runs better. Gravity will deliver enough fuel to run on a topped off tank. If you find the fuel pump doesn't work, I'd test the leads to see if there is 12 volts at the pump with the key switch turned on. If you have electricity to the pump, and the pump doesn't pump, it's probably the pump. If the pump works, then you'll need to move closer to the engine to figure out what's wrong.

If the pump works, I'd suspect the carbs need attention. Float levels, jets or sticking vacuum piston(s) may be the culprit.

I would ask you what you mean when you say you "cleaned" the carburetors. Did you take them all the way apart and replace soft parts (o'rings, diaphragms and such)? Or does that mean you ran some cleaning solvent through the gas? More information is helpful.
I am wrong as often as I am right concerning what is wrong with someone else' motorcycle without having seen the machine in person. Guessing with limited information, as to the source of the trouble, is sketchy at best.

greenmechine
Posts: 4
Joined: Mon Sep 15, 2014 3:14 am
Location: tampa,fl
Motorcycle: 1986 gl1200 a

Re: 86 gl1200 can't get up to 5000 rpm

Postby greenmechine » Mon Sep 15, 2014 8:38 am

I would suggest checking the fuel tank cap to make sure it isn't blocked, creating a vacuum condition inside the tank. That would make the job of the fuel pump harder and can account for the poor performance. HawkeyeGL1200

so you mean , the fuel cap should an air vent ?
i have balanced the carburetor sine i got the problem . so i'll check the fuel pump and the cap.
thank you sir

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HawkeyeGL1200
Posts: 918
Joined: Sat Jul 05, 2014 11:53 am
Location: Courtland, Va.
Motorcycle: 1984 GL1200 Interstate
1981 GL1100 Interstate

Re: 86 gl1200 can't get up to 5000 rpm

Postby HawkeyeGL1200 » Mon Sep 15, 2014 8:49 am

The tank cap is a complicated little gizmo. It has some springs and other stuff built in to act like a pressure relieving device. It isn't supposed to allow too much pressure nor too much vacuum to build up inside the tank. One of these days, I'm going to buy one to take it apart so I can more thoroughly understand it, but it could be part of the problem.

If you are familiar with how a motorcycle sounds when it is running out of fuel. You know the sound and feeling you get when you know it's time to switch over to "reserve" on a tank of fuel? Is that the same "feel" you get when throttling up in the higher gears and finding you're unable to reach the higher speed/RPM?

If so, then I'd say your trouble is fuel related. If it "feels" like you have enough fuel, it could be electrical... like pulse generators.

greenmechine wrote:I would suggest checking the fuel tank cap to make sure it isn't blocked, creating a vacuum condition inside the tank. That would make the job of the fuel pump harder and can account for the poor performance. HawkeyeGL1200

so you mean , the fuel cap should an air vent ?
i have balanced the carburetor sine i got the problem . so i'll check the fuel pump and the cap.
thank you sir
I am wrong as often as I am right concerning what is wrong with someone else' motorcycle without having seen the machine in person. Guessing with limited information, as to the source of the trouble, is sketchy at best.

greenmechine
Posts: 4
Joined: Mon Sep 15, 2014 3:14 am
Location: tampa,fl
Motorcycle: 1986 gl1200 a

Re: 86 gl1200 can't get up to 5000 rpm

Postby greenmechine » Mon Sep 15, 2014 5:37 pm

thank you ,sir . HawkeyeGL1200 .
i just took my friend fuel pump and put it it on my bike . it run better. so it's the fuel pump problem .
i took it out from gl1200 1984. but it's not the original pump .. pump make by misubishi . but it fit .
thank you for your help




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