NEW MEMBER - Question on 1979 GS750L

[Anonymous]

I have 1979 GS750L. It runs great, once it is started. However starting it can be a real bear if it has been sitting a while. I can kill a full battery if I was to use the electric starter, and kicking it requires me to kick it about 50 times or more to get it to turn over. Once it starts it takes a bit to warm up, if I roll the throttle it will kill the bike. I have to keep the choke open and the RPM's up until the bike warms up and then it works GREAT. Very fast, no problems with throttle or anything. Any ideas would be most helpful.
thanks,

[earlfor]

Re: NEW MEMBER - Question on 1979 GS750L

You have blocked choke tubes, or blocked idle passageways, probably both.
Carb synch is probably not as it should be either. Fuel level in the float bowls could also be too low.

Earl

I have 1979 GS750L. It runs great, once it is started. However starting it can be a real bear if it has been sitting a while. I can kill a full battery if I was to use the electric starter, and kicking it requires me to kick it about 50 times or more to get it to turn over. Once it starts it takes a bit to warm up, if I roll the throttle it will kill the bike. I have to keep the choke open and the RPM's up until the bike warms up and then it works GREAT. Very fast, no problems with throttle or anything. Any ideas would be most helpful.
thanks,

[Anonymous]

couple of things that i might try, clean the carbs, then the next one gose without saying but then you must sync the carbs, and a final thought on it might be to check valve clearance. I have no idea if this would fix you're problem or not, but it would be good stuff to have done on the bike anyway.

well, i hope youre bike makes you feel like my old gs dose.

[Anonymous]

One more question in my manual, it says that you have to hold the clutch in when starting the bike, but I think it must be referring to another year, any know for sure on a 79gs750L?

[earlfor]

The bike was manufactured with a clutch lockout switch. Pulling in the clutch allowed the switch to close with energized the circuit to the starter after the ignition was turned on. If you can turn the ignition on and press the starter button (without holding the clutch lever in) and the engine turns over/starts, then someone has jumped the clutch switch lockout. This is pretty common.
I have removed the lockout switches from both my bikes. However, since it is also common to get a false neutral indication at times, if you do not continue with the habit of holding in the clutch when starting the bike, then it is imperative to develop the habit of holding a brake when starting the bike.
If you do not, it is only a matter of time before you will get a false neutral, be standing beside the bike, or sitting on it while its leaning on the kickstand and when you hit the starter, the bike will start, take off, hit something or someone and then the lawyers make things worse.
I always hold the front brake when pressing the starter button.

Earl

One more question in my manual, it says that you have to hold the clutch in when starting the bike, but I think it must be referring to another year, any know for sure on a 79gs750L?

[Anonymous]

Update

Ok, I found my problem, the petcock. It is wierd, I took it all apart and apparently there is some sort of vac system that opens a valve inside the petcock that isn't working.

So, i took it apart and just made it work like a normal petcock and VROOOM! the bike fires right up, but when removing the tank the line that comes out of the side of the petcock near the Reserve side came unpluged, the only place I see where it could have connected is to one of the carbs beside the main fuel line. I believe this is someway a vac tube that is used to open that valve.

Will doing what I have done, cause any problems? I sure hope not, cause now that I am getting fuel, it has never ran better!

[jknappsax]

Fuel into oil

If you are not using the vacuum-actuation of the original petcock, there is a chance that since you do not have the positive fuel cutoff, you could get fuel leaking through the carbs , washing the lubrication off the cylinder walls, and ending up in the sump, adversely affecting both bore wear and lower end bearing wear. A rebuild kit for the petcock is about $30 and available through K&L, or a lot of people replace the vacuum-operated petcock with a regular Pingel petcock. Also, by plugging the hose on the carb vacuum port, it may work correctly, unless you have modified the petcock.

[Anonymous]

But if I have modified the petcock to not let fuel leak when in the off position do I still run the risk of creating problems. I will probably just buy the rebuild kit or replace with a pingel. But I wanted to know in the mean time.

Is there a chance that the vacuum isn't working at all and that is why the valve isn't opening in the original petcock? If so, how is that fixed?

[mk]

The problem you're having is exactly what happened to me when I bought my 79 GS750L last year. After killing the old battery doing "long starts", I decided the plugs might be worn out and replaced them with the NGK iridiums. Immediately after that, the bike would start within 2 or 3 cranks when cold. Now, about 600 miles later, it takes more tries but nothing close to running the battery down.

My bike also needs warmup time and, for about the first half mile of riding, giving it throttle makes it "bog down" for a couple of seconds, then accelerate. After that it runs and starts perfectly the rest of the day.

If you find out what was causing the problem, let me know so I can make the change on mine .

[TheNose]

The problem you're having is exactly what happened to me when I bought my 79 GS750L last year. After killing the old battery doing "long starts", I decided the plugs might be worn out and replaced them with the NGK iridiums. Immediately after that, the bike would start within 2 or 3 cranks when cold. Now, about 600 miles later, it takes more tries but nothing close to running the battery down.

My bike also needs warmup time and, for about the first half mile of riding, giving it throttle makes it "bog down" for a couple of seconds, then accelerate. After that it runs and starts perfectly the rest of the day.

If you find out what was causing the problem, let me know so I can make the change on mine .

Read about three posts back. :roll:

Terry