This is probably going to sound stupid but...

[Detman101]

Exactly what happens when you warm up the bike?
Exactly what parts are warming up/expanding?
I only ask this because my brain won't shut up with the questions and I don't ahve all the answers. I know the pistons and the block get hot but does anything happen with the carbs?

Dm of mD

[lhanscom]

Oil is the biggie. combustion chamber needs to warm up too for better burning. Not sure what else happens.

[Detman101]

Hmmm...better burning eh?
Perhaps that explains why this thing eats so much gas.

Dm of mD

[lhanscom]

That's why you need the choke, I think. It requires more gas when it's cold.

[Anonymous]

I'm great at hijacking other people's threads for my own use.

I don't typically warm up my bike. I've been getting up and going. Last year it was not a problem - at least I did not notice one.

This off year, I had the carbs cleaned, readjusted, etc. and had a tune-up.

The bike starts nicely, but I notice when I take the choke off, it takes a good 10-15 minutes of moderate riding before it will idle correctly. Also, when I give it full throttle (it is a GS1100E), before it is warmed-up, it lags and acts like it is low on gas. In normal circumstances, I can't give it full throttle too often unless I want to bring the wheel up, or hit the rear end of a car in traffic.

After the 10-15 minutes, the bike runs wonderfully, better than it ever has and idles nicely at 1.5 rpm's.

BUT, I've been only getting about 35 MPH per gallon, if that.

Should I spend more time warming it up or does riding it gently suffice as a warm up. Is the only danger the inefficient use of gas, or am I screwing up my engine?

[lhanscom]

I don't think you're hurting your engine. I think you are running rich, it may just be the mixture screw needs to be turned in a little. You may want to take the carbs off and check all the settings, your float level may be off. Have you done any mods to the bike? Exhaust, pods, etc?

[10yeareer]

Though I don't always practice what I preach, I think its always a good idea to let an engine warm up for a couple of minutes before taking off. The main reason is to allow the oil thats sitting in the bottem of the motor to warm up and coat everything before putting the engine under load.

As for the carb, cold air = denser air = leaner mix. Thats why you choke a cold engine. The choke creates a richer mix. When your bike is cold, and you have the choke off, you are running lean. Thats why it stalls when you wack open the throttle on a cold engine without the choke.

I recently did a rebuild/sync on my carbs. I adjusted the mixture screws for the highest idle. However, fully warmed up I would wack open the throttle and the engine would die. I loosened the mixture screws in 1/4 turn increments until I could wack open the throttle without it dieing.

[Detman101]

Aha, I see now. It's the leanness of the initial mixture...
Well, I'm getting 90 miles to the main tank on an 81 gs750L.
I think it's a 4 gallon tank so that is 90\main tank(possibly 3 gallons?) and that means I'm getting 30 mpg. Great mileage...for a car. I was hoping for at least 40 or more. But with pods and stage-3 I can't ask for too much I guess. Time to just find a bigger tank. I can't see riding to nyc this may and having to stop every 90 miles. I'm doing worse than my cousin's 2003 sportster with a smaller tank.

Perhaps I could fit a 5 gallon sportbike tank onto the bike....Hmmmm.....


Dm of mD

[Detman101]

I'm great at hijacking other people's threads for my own use.

This off year, I had the carbs cleaned, readjusted, etc. and had a tune-up.

The bike starts nicely, but I notice when I take the choke off, it takes a good 10-15 minutes of moderate riding before it will idle correctly. Also, when I give it full throttle (it is a GS1100E), before it is warmed-up, it lags and acts like it is low on gas. In normal circumstances, I can't give it full throttle too often unless I want to bring the wheel up, or hit the rear end of a car in traffic.

After the 10-15 minutes, the bike runs wonderfully, better than it ever has and idles nicely at 1.5 rpm's.

BUT, I've been only getting about 35 MPH per gallon, if that.

Should I spend more time warming it up or does riding it gently suffice as a warm up. Is the only danger the inefficient use of gas, or am I screwing up my engine?

I am experiencing the EXACT same thing!!! If I ride off before it is warmed up it will die down and cut off at stoplights. After riding for about 5 blocks and shifting at 4k rpm points it warms up enough to idle at 1100.
My vulcan750 runs a little richer than stock and doesn't get this long warm-up period in the mornings. I would richen the gs but it breathes enough gas as it is.

Dm of mD

[lhanscom]

I would richen the gs but it breathes enough gas as it is.

Keep in mind that you will actually gain gas mileage by richening the mixture if it is off. You'll make the burn more efficient, and will get more power for less throttle opening. Making the end result burning less gas.

The best way to figure this out is to read the plugs. Get to the circumstance that you're having a problem, hit the kill switch and pull the plugs. Black is rich, white is lean, tan is good. Lean will kill a motor, rich won't, so I like to start rich and work towards tan.

[Detman101]

I'll see this weekend.
I don't want to throw off the carb settings but I don't think I'll do too much mayhem to the mixture by richening it a little teensy bit.


Dm of mD

[lhanscom]

Just make sure that you write all the settings down, so you can go back if you need to.