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I have several 500s, 3 GLs and 1 CX. The CX and one GL are parts bikes. The CX could be a runner but the PO took the ignition box off before I bought it.

These are all 1981.



My problem is this; The one GL I use as a daily driver has one major flaw. When I'm doing slow speed manuvering in the parking lot or any where I need to creep I have to really ride the clutch carefully.



As I begin to slowly roll in a little throttle it feels like nothing's happening then suddenly the engine revs alot completely missing the very low speed just off-idle area of the RPM band. The bike lurches forward violently enough to fully extend the forks as the front of the frame raises up from the torque.



Has anyone on the forum sent their carbs out for a rebuild or done them themselves and found the throttle shafts were sticking? Are these shafts a problem area on these carbs?



I am an ASE Master Tech for automobiles however I'm trying to get a handle on the quirks of these twisted engines.



Any help I can get with this problem will be greatly appreciated. If the carb rebuilds are straightforward I can do that with no problem.



Thank You for all your help



Danno
 

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I have recently rebuilt my carburetors, according to the most excellent method lined out in Larry Cargill's cool carburetor book. One of the steps in his method is to oil the felt seals where the shafts penetrate the carburetor bodies. I also oiled the shafts from inside the carburetors as well, along with all of the coil springs. My carburetors react very smoothly now.
 

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Sounds like you may have some jets plugged in your carbs.....the carbs should supply the engine progressively with fuel with slight throttle changes. You may have a dead spot. Check out the carb rebuild/cleaning threads.
 

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Does your bike idle ok? Have you ever removed the plug wires when it was idling?



I would try removing the left plug wire when the bike is idling and see if there is any difference in rpm. Then replace the wire and repeat on the right side.



If the bike quits when you remove a wire then that side is working. If it makes no difference then that side is not working at idle.



The idle circuit feeds fuel at idle and also between idle and when the main jet starts to work. If you have a plugged idle circuit in one of the carbs you will get a similar symptom as you describe. There are 3 small holes in the venturi of the carb, one of them is where the idle mixture screw is and the other 2 are just past that. If the idle jet is plugged none of these will feed fuel to the engine.



The pic below shows the idle circuit. You should check to see if the holes are clear,,Also check to see if both butterflies open at the same time and I would watch the carb throttle mechanism when you slowly twist the throttle grip to see if it is pulling the mechanism open smoothly.



 

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Another item on the checklist should be to check the throttle cables for damage or binding. Get the bike on the centre stand with the front wheel off the ground and crank the bars back and forth listening for changes in idle speed.



The key word being 'checklist'. All the advice listed here certainly applies and should be part of a maintenance checklist. That's dangerous sh!t when your throttle gets possessed.
 

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I have the same problem. Kinda seems like the cable might be sticking a bit, but only sometimes. Carbs couldnt be cleaner, oiled the felt, spring is great, cable is new, greased the throttle tube and packed grease inside where the cable attaches. Only running one cable... no return cable. Not sure if that is it or if I do not have the throttle free-play adjusted correctly. Lifted the front wheel off the ground today for the first time due to this, but that was fun
Ok.. part of that might have been my fault and dumping the clutch a little to fast, but always having to compensate due to the throttle seeming "sticky" did play a part. Just feels tight. I'm going to try the free-play adjustment, that's where my moneys at.
 

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That's dangerous sh!t when your throttle gets possessed.


Relatively new to these bikes, I have parked my bike, turned the bars to the left used the right bar for a helmet hanger...well the helmet would lock down the cruise lever. This goes unnoticed until you go to hit second gear after a hard accel in first!!! Bike nearly red-lined when I pulled in the clutch and the throttle didnt snap back
 

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Relatively new to these bikes, I have parked my bike, turned the bars to the left used the right bar for a helmet hanger...well the helmet would lock down the cruise lever. This goes unnoticed until you go to hit second gear after a hard accel in first!!! Bike nearly red-lined when I pulled in the clutch and the throttle didnt snap back




Our MOT(Road Worthiness Certificate) is very strict on this over here in the UK Rick.That would fail the test and the bike would be illegal.Over here you must be able to turn the handlebars from lock-to-lock and the engine speed not alter.

This confirms that the control cables are in good condition etc.
 

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Our MOT(Road Worthiness Certificate) is very strict on this over here in the UK Rick.That would fail the test and the bike would be illegal.Over here you must be able to turn the handlebars from lock-to-lock and the engine speed not alter.

This confirms that the control cables are in good condition etc.


He is talking about accidentally engaging the cruise control.
 

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Our MOT(Road Worthiness Certificate) is very strict on this over here in the UK Rick.That would fail the test and the bike would be illegal.Over here you must be able to turn the handlebars from lock-to-lock and the engine speed not alter.

This confirms that the control cables are in good condition etc.


I think we both pass the stop to stop test. And it snaps back, not hard but not delayed. Maybe needs to be a little looser. Wonder if a return cable would make a difference.
 

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I think we both pass the stop to stop test. And it snaps back, not hard but not delayed. Maybe needs to be a little looser. Wonder if a return cable would make a difference.


The cable routing is the key and a right Royal PITA.I had to modify my carbs a little after fitting AM cables as the B,"Push" cable was a little tight in it's inner so I ground a bit off the brackets to give it a little play in it,







I will also dispute anyone saying that the B push cable does not matter or that it doesn't,"Push".It does push.This is easily tested when the cables are off the carbs.Just place your hand in front of the end nipple and operate.You will feel the pushing force.

It's not strong but then doesn't have to be as the springs in the Tops of the Constant velocity carbs are weak as most of the required closing is by Gravity and vacuum but the Push cable aids this.



Never having run without the Push cable I cannot say what kind of engine braking you get with just a Pull cable but the engine braking on my CX500s is a joy.



I have no doubt that a perfectly set up set of carbs with perfect cable routing and linkages the Pull cable will do the job on it's own but for the cost of the B cables I don't see the point in trying to out-think Honda on this one.



 
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