Two starting questions.

[Anonymous]

My '81 GS650 has two issues when it comes to starting.

1. If I depress the starter button, it just cranks and cranks and cranks and doesn't even pretend to start. The instant I release the button it will fire. If it is warm outside, then it will usually continue running. It seems like I only get spark for a microsecond right before the cranking stops.

2. If it is cold and/or damp outside, then in order for #1 above to work I have to lightly blow into the carb overflow tubes. There is usually some displacement of air, then I repeat #1 and it starts. I really dont' know what this does, but if I blow too much air into the tubes, it starts like it is flooded. I had some previous carb and petcock issues here that may be contributing to the problem.

When the bike is warm it starts instantly and runs like a champ! Plugs look fine and are pretty uniform in their burn.

Any ideas or strategies for troubleshooting?

[earlfor]

Re: Two starting questions.

Sounds like a low voltage problem. The starter engaged pulls the voltage down and as soon as you let off the starter, voltage rises and it fires and starts. Possibly low volatage at the battery. Battery terminal voltage should be at least 12.5. Possibly corroded battery ground wire, loose electrical connections to the coils or dirty connections. Can you turn your headlight off before trying to start the bike? That will help to start, but it will do nothing to eliminate the cause of the problem. Also, its probably a good idea to remove the back cover of your fusebox and check the inside connections to be sure they are clean. Corrosion loves to hide in there. :-)


2. Blowing into the carb overflow tubes would force fuel up into the carb throat, richening mixture. Blow too much and you get too much gas, so it starts like its flooded because it is. :-) Probably choke cable not having full travel, or choke tubes partially blocked, or float bowl fuel level slightly too low.

Earl

Earl

My '81 GS650 has two issues when it comes to starting.

1. If I depress the starter button, it just cranks and cranks and cranks and doesn't even pretend to start. The instant I release the button it will fire. If it is warm outside, then it will usually continue running. It seems like I only get spark for a microsecond right before the cranking stops.

2. If it is cold and/or damp outside, then in order for #1 above to work I have to lightly blow into the carb overflow tubes. There is usually some displacement of air, then I repeat #1 and it starts. I really dont' know what this does, but if I blow too much air into the tubes, it starts like it is flooded. I had some previous carb and petcock issues here that may be contributing to the problem.

When the bike is warm it starts instantly and runs like a champ! Plugs look fine and are pretty uniform in their burn.

Any ideas or strategies for troubleshooting?

[Redman]

1. I agree with above posting. Have had similar experience myself. Is first noticable indicator of battery getting weak (or charging problem and battery not fully charged, but I suspect just weak battery). When cranking the starter motor the current draw is loading down the battery voltage, which is lowering the voltage to where the ignition is not working properly. When you relaese the starter button, the current draw stops and battery voltage comes back up almost immeadiatly and ignition starts to operate while motor is still turning.

2. No idea.

[Anonymous]

Thanks for the tips... I think I take tomorrow off and get acquainted with the electrical system diagram in the stator papers and my multimeter.

[earlfor]

Before checking the charging system, check all the connections to be sure they are clean and tight. You can have a perfectly normal charging system, but it will not be able to charge properly if the connections are poor.

Earl

Thanks for the tips... I think I take tomorrow off and get acquainted with the electrical system diagram in the stator papers and my multimeter.

[SqDancerLynn1]

I would also clean the stop/run switch, it could cause the problems you are having