Very cold start tips?

[olilem]

I have a gs750 from 1981. It runs beautifully, without any issues, idles good at around 1200 rpms. Starts right up when taking it out of my garage.
But lately when I ride to work in these 40 degree weather we're having in ohio, the bike just does not want to start at night after having sat in the cold for 8 hours. I have to crank it for what feels way too long, with a growing fear of "am I just flooding the crap out of it?).
Like I said, the bike usually starts beautifully, carbs are perfectly clean, it cranks very good, battery is good, recharging system is brand new and it all works fine.
It just takes a good 30 seconds of trying to start it (which when stranded an hour from home seems like a good hour).
The only possible problems could be the valve adjustment, or the ignition (but I'm not sure if it is electronic or points).
My friend who helps me on working on the bike sometimes tells me "its an 80's carbureted bike, it won't be happy starting when its cold" But I really don't want it to be that simple.
If there is any possible problems, id be happy to know.
Any insight would be awesome!

 

[GateKeeper]

Full choke, no throttle, hit the start button.....

your friend might be right, I have an 83 and am just getting the cold weather, I will see how mine reacts and starts over the next few days....

 

[olilem]

Oh yeah I forgot to mention that I am indeed using the choke. (and there is gas in the tank) That one isn't an issue. haha

 

[BassCliff]

Hi,

For easy starts; properly adjusted valves, clean carburetors, proper float height, tightly sealed intake system (airbox, intake boots, etc), and clean electrical connections are necessary. I think your bike may just need maintenance. My bike starts with just a touch of the start button, even in a 40? garage.

Have you checked for spark? Is it strong or weak? You may want to check the voltage at the coils, both at rest and during cranking. Ideally you want to see the full battery voltage (12v+) at the coils at rest and more than 10v during cranking. If your wiring harness has many dirty and corroded connections, or the wiring is just old and compromised that there is too much loss, you can try the coil relay mod to insure full battery voltage at the coils. Have you replaced the spark plug caps?


Thank you for your indulgence,

BassCliff

 

[Steve]

I have to crank it for what feels way too long, with a growing fear of "am I just flooding the crap out of it?).

If you are cranking for more than two or three seconds, you need to catch up on some of your maintenance.

It just takes a good 30 seconds of trying to start it (which when stranded an hour from home seems like a good hour).
The only possible problems could be the valve adjustment, or the ignition (but I'm not sure if it is electronic or points).

30 seconds of cranking is not good for the starter or the battery.

You would be amazed at what a valve adjustment will do for you.

Your '81 bike will have electronic ignition, not points.

My friend who helps me on working on the bike sometimes tells me "its an 80's carbureted bike, it won't be happy starting when its cold" But I really don't want it to be that simple.

Carbureted bikes from the '80s start JUST FINE, thank you very much.

When the carbs are clean and properly adjusted, and the valves are properly adjusted, the bike will start just as easily when it is cold as when it is warm.

.

 

[olilem]

Thanks for the tips.
And 30 secs might have been an exaggeration. But it just feels too long, when on a normal day it start at a touch of a button.
And as cliff pointed out, it probably is a simple issue of maintenance, I bought the bike after it sat for 6 years in a barn. So it was a very sad sad GS. I have cleaned the carbs, changed a few fuel lines, changed the tires, changed the chain, cleaned the gas tank, changed carb boots that had leaks, changed the stator and rectifier system. And it is slowly becoming a great running bike. The thing I have yet to do is adjusting my valves, and maybe change the plugs. They seem in good condition, and they are sparking. But they are old. Which worries me.
I hope after the valve adjustment, things will be good.
The ignition system seems to be in good running order, the voltage is perfect before, during and after start. Only issue is when it is left out in the 40 degree weather for 8 hours, where it is just not happy to be woken up. Cranks perfect at a normal speed, and I hate to crank it for long.
Thank you steve and cliff for the tips, glad to see it is indeed a fixable issue.

 

[Steve]

By the way, welcome to the "southwest oHIo group".

I have 29 on my list so far, and I'm sure I don't have them all.

.

 

[olilem]

By the way, welcome to the "southwest oHIo group".

I have 29 on my list so far, and I'm sure I don't have them all.

.

Thanks! I just recently moved to Cinci, Ive started to get to know some of the "assfault junkies" very nice group of riders from the area. Lots of cool guys.
But im always looking for people to ride with, considering I don't really know people around here. lol

Full choke, no throttle, hit the start button.....

your friend might be right, I have an 83 and am just getting the cold weather, I will see how mine reacts and starts over the next few days....

And I just checked out your build, oh my, amazing work you have put towards your ride.

 

[1_v8_merc]

What Cliff said.

If she won't start in the cold, it's Spark.(or fuel)
These bikes are 30 years old, the voltage that "actually" gets to the coils is Much less than when they rolled off the factory.
I would Highly recommend reading up on "coil mod", to get a description of this.
(basically you can Boost your coils directly to the battery, or replace the old wiring)

Yes, of course the bike runs fine,"once" you get it warmed up, you've already got the reaction started...you can run on weaker spark.
But trying to start in the cold is where you see the first signs of weakening spark.

 

[Johno]

Yes, correct valve adjustment makes a huge difference - do the maintenance.

 

[BentRod]

Not that I would really recomment this to anyone, I am going to say it anyways. When I had trouble with my 81gs400 on cold mornings I would use a propane torch (cringe) and heat one or both of the cylinders. Have to be careful not to heat just one spot or you will cause problems, but evening raising the temperature will help the fuel to vaporize better in the cylinder, and ignite more easily.

Again, I would not recommend this, and you are more likely to cause damage, but it does work really well. Garage heaters are also a good idea.

 

[tkent02]

Not that I would really recomment this to anyone, I am going to say it anyways. When I had trouble with my 81gs400 on cold mornings I would use a propane torch (cringe) and heat one or both of the cylinders. Have to be careful not to heat just one spot or you will cause problems, but evening raising the temperature will help the fuel to vaporize better in the cylinder, and ignite more easily.

Again, I would not recommend this, and you are more likely to cause damage, but it does work really well. Garage heaters are also a good idea.

Sounds good, it's nice to have a system that works. I'd rather flip the choke on and tap the starter button myself .

 

[Guest]

not meaning to crash on the newb, but, another cold start thread? sorry, grumpy cause the bike is temporarily out of service. carry on.

 

[Steve]

not meaning to crash on the newb, but, another cold start thread?

Actually, it's another "cold, NO start thread".

 

[olilem]

Well I will check all those things this weekend.

One silly question too, internet says my gas tank is 3.8 gals. the issue is when I fill up when the gauge reads empty, I can only get in about 2.3 gallons. Where should I look to fix? in the gauge or in the tank? Or is that just completely normal

 

[tkent02]

You can calibrate the gauge to read empty when it's empty and just touch the red right when it goes on reserve.