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Discussion Starter #1
I have a 1982 gs650g that will not start. It has good spark (blue and rapid), carbs are rebuilt and cleaned, no shorts, it does not have an air box it is open carbs but I was told it can run like that so I was gonna just adjust it to run that way. This is my first bike so I’m not familiar with them. Is there anything I’m missing??? As far as I can think the bike needs three things. Gas, air, spark. I’m sure I’m wrong so that’s why I’m here I’m not sure where else to go. If anyone can throw me some advice I would really Appreciate it.
 

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As you say three things to run...you dont mention fuel. Also without an air filter it is most likely running very lean and starting needs extra fuel. Some sort of filter is needed and fuel supply needs looking into.

Pull the plugs to check if they are dry. Check fuel is flowing from the tank and its clean and free from debris. Any debris in the fuel will almost certainly have blocked the idle circuits and these will need to be cleaned. Crud can be removed using a good carb cleaner and leaving it overnight ,if possible to do its job.

Your bike is not likely to have a fuel valve so a vacuum hose is not probably present....however I may be wrong and if so there should be a small hose connected to the rear of the valve and the other end to a port on one carb. If this is missing or defective then you can turn the valve to PRI . This opens the valve to a gravity type feed. It is not advisable to run the engine on PRI for long periods.

If its a normal on/off fuel tap then turn it to run....if no luck try reserve. The tank filter may be clogged so an inspection may be a good idea. Do not be tempted to run without one as debris can then enter the carbs causing further headache

If you have CV carbs....probably...then you may want to pop the top off the carbs to check the diaphragms are not holed. You will get little to no movement of the slides if they have any pinholes in them....hold them up to the light to see any tiny holes if present. Pay particular attention when re-installing the slides/springs to make sure the do not tangle up.

A good fully charged battery is a must. Also any safety cutouts....ie the clutch and side stand switches may be faulty and a simple disconect and jump will identify any that are.

Most kill switches work by cutting the starter circuit but yours may not so check the switch is in the run position and that it is functioning properly.

One other thing is drain the float bowls...even to the extent of leaving the tank valve switched on till fresh fuel flows...good idea to have a jar to catch it in....you dont want raw fuel lying around. It could be water has entered the carbs and being heavier than fuel it collects around the fuel pickup preventing fuel being sucked up into the venturi/airflow.

Finaly check the tank vent...pop the cap it may be a vacuum preventing fuel flow from the tank.

Thats about all I have atm so good luck
 

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Discussion Starter #3
As you say three things to run...you dont mention fuel. Also without an air filter it is most likely running very lean and starting needs extra fuel. Some sort of filter is needed and fuel supply needs looking into.

Pull the plugs to check if they are dry. Check fuel is flowing from the tank and its clean and free from debris. Any debris in the fuel will almost certainly have blocked the idle circuits and these will need to be cleaned. Crud can be removed using a good carb cleaner and leaving it overnight ,if possible to do its job.

Your bike is not likely to have a fuel valve so a vacuum hose is not probably present....however I may be wrong and if so there should be a small hose connected to the rear of the valve and the other end to a port on one carb. If this is missing or defective then you can turn the valve to PRI . This opens the valve to a gravity type feed. It is not advisable to run the engine on PRI for long periods.

If its a normal on/off fuel tap then turn it to run....if no luck try reserve. The tank filter may be clogged so an inspection may be a good idea. Do not be tempted to run without one as debris can then enter the carbs causing further headache

If you have CV carbs....probably...then you may want to pop the top off the carbs to check the diaphragms are not holed. You will get little to no movement of the slides if they have any pinholes in them....hold them up to the light to see any tiny holes if present. Pay particular attention when re-installing the slides/springs to make sure the do not tangle up.

A good fully charged battery is a must. Also any safety cutouts....ie the clutch and side stand switches may be faulty and a simple disconect and jump will identify any that are.

Most kill switches work by cutting the starter circuit but yours may not so check the switch is in the run position and that it is functioning properly.

One other thing is drain the float bowls...even to the extent of leaving the tank valve switched on till fresh fuel flows...good idea to have a jar to catch it in....you dont want raw fuel lying around. It could be water has entered the carbs and being heavier than fuel it collects around the fuel pickup preventing fuel being sucked up into the venturi/airflow.

Finaly check the tank vent...pop the cap it may be a vacuum preventing fuel flow from the tank.

Thats about all I have atm so good luck
Thank you man. That’s a lot of help. Just to give you more idea I have battery tender on it at all times so battery is charged. I completely rebuilt carbs. Everything on that end looked good. It is a vacuum system and the lines look good on visual inspection. I did mention it is getting gas(fuel) as it is trying to fire on starter fluid and sometimes I’ll get a fire on just gas itself. Without the air box I’m guessing that is causing not enough restriction and it is trying to run too lean. That is what all signs are pointing at. I am gonna run through this check list tho just to make sure. Thank you for taking the time to help man.
 
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