cold operating temps lead to very poor performance

[qwqb]

So I've been having this issue with the gs850 where at cold operating temps, there is an extreme lack of power. I need to give it 1/2 to 3/4 throttle just to get the bike to move from a dead stop without dying. From there on it is a struggle to get the bike to continue accelerating.

After riding for about 15 minutes or so, once the engine gets nice and warm, the bike starts running like a champ, and has all the power in the world.

Assuming there are no other variables other than the engine warming up, I'm not sure why the change in temperature creates this great of a change in performance.

Any suggestions are much appreciated. Thanks guys.

Other Info:
Carbs have been disassembled, dipped, o-rings replaced.
Intake boots/o-rings replaced.
Valves adjusted

 

[Larry D]

Although you said the valves have been adjusted....I'd check them again to be sure. The symptoms you describe indicates the bike needs a valve adjustment.

 

[BassCliff]

Hi,

Yes, the valve clearances are my first suspect too. How about dragging brakes? Have you checked those?

Are you sure it's engine related? Is all the other maintenance up to date? Bevel gear oil? Final drive oil? Have you checked the spark when it's cold and then when it's hot? Is there any difference?


Thank you for your indulgence,

BassCliff

 

[qwqb]

I guess I will have to re-check the valve clearances and re-adjust as necessary.

It definitely seems to be engine related. All fluids were replaces in the late winter, as this is when I bought the bike.

I will also check the spark at the different operating temperatures. How does the temp effect the spark?

 

[UncleMike]

Are you letting her warm up fully with the choke on?

 

[DanTheMan]

Depends on your version of cold. Below 40 deg F, I have to let mine warm up on choke for about 5 minutes before it's ready to roll. Mine performs best with the intake air real cold. But, valves too tight will have an effect on the performance. My bike is operating every year until the roads aren't safe due to ice and snow, and as soon as the ice is out of the bottom of my driveway I'm riding. Last day riding last year was the second week of November, first day this year was the second week of March.

 

[BassCliff]

I will also check the spark at the different operating temperatures. How does the temp effect the spark?

Hi,

I was just thinking that some of the electronic ignition components may be thermally intermittent. For example, sometimes coils will seem fine when you first start up but will then start to fail once they get good and hot. Maybe the igniter works great when warm but not when cold. I'm just speculating here. But I would check the spark when cold and then again when hot to see if there is any difference.


Thank you for your indulgence,

BassCliff

 

[gearhead13]

Check the plugs, how do they look?
Does it run on all 4 when cold?
Richen the idle/pilot circuit. Bikes that run better when hot are usually lean. Does it pop under deceleration?
Mine takes less than a minute to come off choke.

 

[BassCliff]

Hi,

Yes! Spark plugs are cheap. Just put a new set in. I've read here many times where that's all that was needed to fix many kinds of wierdness.



Thank you for your indulgence,

BassCliff