RE: Warming up bike before driving
 

I would assume this applies for bikes. I've always heard that for cars you should immediately start driving the car when it's cold, and not to let it sit at idle. The reason being, a lot of wear and tear can occur at startup because at startup all the oil has drained to the bottom of the engine, thus limiting lubrication at other parts of the engine. By driving it immediately, it quickens the spread of the oil throughout the engine.

RE: Warming up bike before driving
 

I am new to motorcycles and I think its amazing how high these things rev, just for that fact, I want to have my oil all warmed up and circulating before I take it out.


Also, I'm not sure what temperature the t-stat opens, but I think its a good idea to warm it up to open the t-stat to get the coolant flowing. Once the coolant is warmed up more, it will take less time for the t-stat to open. If you start the bike cold and ride it hard right away, the temperature around the cylinders will increase dramatically because the coolant is still "cold" and it will take longer for the t-stat to open which means longer for the coolant to cool the engine. This might cause some knock.


Maybe I'm wrong...?

RE: Warming up bike before driving
 

I guess I don't see how driving the car quickens the spread of oil, or in a bike. I think the only thing you are doing is putting load on the engine with cold oil that isn't properly circulating yet, which I think would be a bad thing.

RE: Warming up bike before driving
 

As long as you don't rev the engine too high at startup it should not make much of a differance.

RE: Warming up bike before driving
 

when i used to keep my bike outside, it would rev up to 2800-3100 idle until warm, then drops back down...
now it's in my warm garage, starts and is about the same as regular idle or maybe higher sometimes...

RE: Warming up bike before driving
 

On every bottle of motor oil there is a seal that gives you three pieces of information:

The API service rating
The viscosity grade
"Energy Conserving" indicator (it either is or it isn't)
The API service rating is a two-letter rating that tells you the type of engine the oil is meant for (gasoline or diesel) and the quality level.
The viscosity grade (for example, 5W-30) tells you the oil's thickness, or viscosity. A thin oil has a lower number and flows more easily, while thick oils have a higher number and are more resistant to flow. Water has a very low viscosity -- it is thin and flows easily. Honey has a very high viscosity -- it is thick and gooey.

The standard unit used to measure viscosity is the centistoke (cSt). According to the Automotive and Industrial Lubricants Glossary of Terms:

Viscosity is ordinarily expressed in terms of the time required for a standard quantity of the fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. Since viscosity varies inversely with temperature, its value is meaningless unless accompanied by the temperature at which it is determined. With petroleum oils, viscosity is now commonly reported in centistokes (cSt), measured at either 40°C or 100 °C (ASTM Method D445 - Kinematic Viscosity).
The centistoke rating is converted into the SAE weight designation using a chart like the one shown on the Superior Lubricants Web site.
Multi-weight oils (such as 10W-30) are a new invention made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscosity of the oil at a cold temperature, while the second number indicates the viscosity at operating temperature. This page from the Sci.Electronics.Repair FAQ offers the following very interesting description of how the polymers work:

At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.

RE: Warming up bike before driving
 

Does it say anything in the manual?

The idea of allowing the oil to spread through the engine before riding does sound reasonable BUT given that car manuals do state that it is BETTER to drive right away this just may not be the case.

Of course we can all agree that keeping the revs low (3500-) while cold is a good thing.

I just like the idea of not having to wait around staring at my bike for a couple of minutes before getting on :)

RE: Warming up bike before driving
 

This is what I was saying in my previous post. I'm not sure about the mechanics of what is going on, but perhaps by driving the thing immediately, the increased oil pressure from driving it allows the oil to spread quicker.

RE: Warming up bike before driving
 

I said - when oil gets hotter it gets thinner.

You initially said " With 10-40W oil Its 10w when it starts up cold then turns to 40W (thicker)when hot" - the only part I disagreed with was your statement that it is thicker when hot... I'm sure it was a typo now that I think about it.

In your second post back to me you stated the correct thing - oil when cold is thick, that the first number is it's cold value, and that when warm it get's as thin as the second number. Infact, that was a great description of what the numbers actually mean.

Essentially - we're both saying the same thing - what you said the first time should read

"With 10-40W oil Its 10w (thicker) when it starts up cold then turns to 40 (thinner)when hot"

RE: Warming up bike before driving
 

For reference:

http://www.autoeducation.com/autoshop101/oil-change.htm

Example: 10w30; 20w50

10w flows through faster than 40w, because it is thinner (WHEN COLD as the W test is at 0 C)
30 vs 50 is the high tempature test... the 30 runs through faster than the 50 does.

Since the tempature is different between the W test and the (non-W) high tempature test, we can't compare the numbers. I'd also suspect that the hole that is used to test at high tempatures is smaller, because the higher numbers indicate longer flow times and because we would expect lower numbers with hotter/thinner oil than the same oil when cold.

Sorry for going off topic... I first was sure I had done it properly. Then I doubted myself and had to look it up... if this helps clear it up for other people then it wasn't a purely foolish thread jack.