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For those of you are in as cold of a climate as I am, you may find this article by Joe Minton /American Rider magazine October 24, 2005 an interesting read. After having my bike in storage for the past month, I have a bad itch to go for a ride despite the cold.

Engine warm-up is important and is a good idea that we all know something about the matter. Safety is the most important reason to warm an engine before riding. Most stock engines tend to lack power and deliver uncertain throttle response until they have run for at least a few minutes. In fact, some engines will stop running altogether if the throttle is quickly and fully opened immediately after they are started. If that were to happen in front or someone running a stop sign with their SUV, well.... This kind of scenario, by the way, is the main reason manufacturers often recommend long pre-ride warm-ups.
Many of the motor parts inside your Harley engine do not fit and work together well until they are at or near normal operating temperatures. I think the best example is the cylinder-and-head stack. Evo, Sportster, and Twin Cam engines have aluminum cylinders, heads and rocker boxes. However, the studs that hold those parts together are steel. The difference in the temperature-related expansion rate between aluminum and steel is about 10 to one. Thus, the head gaskets are squeezed much tighter after the motor is hot. Early Evos would often blow head gaskets if they were given full throttle before the cylinders and heads were warm. The earlier Shovelheads and Iron Sportsters did not have this problem and, at least in this one respect, were superior designs.
Lets look at our street Harley motors and how we use them. Most of the time we are asking them to produce less than 15 Horsepower when traveling at steady speeds. About 10 horsepower are needed to push a Sportster down a flat, windless road at 60 mph. An FXD or bare Softail needs 11 or so and a full touring rig about 13. This isn't much of a load for an engine capable of producing 60 peak horsepower.
I can assure you that Harley-Davidson has spent many hours and miles refining the piston, ring, valve guide and other dimensions to serve this standard load. They have also had to allow for the occasional extremes which include "seeing what she'll do" and the stresses of abusive warm-up.
The extra ring end-gap needed to ensure there is no binding during long full throttle runs allows blow-by when the gap is wider, as it is when the engine is cold. The ring end-gap must be large enough for a hot engine and is likely too large in a cold engine. There are other such compromises like piston skirt-to-cylinder clearance and cylinder-head torque. If you were to make sure your Harley motor were completely warm before using full throttle to get up to 100 mph, you could run the piston clearance within a half-thousandths of an inch of the cylinder walls instead of the standard two-thou (or so). Harley must certainly assume that you might not do that and fits pistons accordingly.
So, what is a person to do to properly warm-up the engine? Basically, give the motor a chance to swell up and get its clearances together. The bit of extra piston/cylinder clearance or piston ring end gap won't matter if you keep the loads and rpm moderate during warm-up. The lower clamping pressure holding the heads in close proximity to the cylinders aren't so important at half-throttle.
Why not just let the engine idle until it is warm? This is important. A cold engine generally needs the choke to run at all. Chokes are relatively crude devices and dump too much fuel into the engine, more than it needs. This extra fuel washes oil off cylinder walls, finds it’s way past loose pistons (and ring gaps) and down into the oil. Other byproducts of combustion find their way into the crankcase and engine oil as well. These include: water, acids and carbon particles.

The best way to minimize all this contamination is to warm the engine as quickly as is reasonably possible. "Reasonably possible" includes placing a load on the engine by actually riding the bike. One or two horsepower are needed to idle an engine, but it takes 10 or so to go down the road. More horsepower develops more heat; hence, the heat from the 10 warms the motor faster, reducing corrosive oil and engine contamination.
If you keep revs below halfway to redline and the throttle below one-half, you'll have no trouble with blow-by or overstressing cold and still loose parts. Long ago, before emissions standards and too many lawyers with time on their hands, General Motors learned that engines lasted longer if they were warmed by driving the car. I have ridden with that recommendation in mind for 40-plus years and preached it to thousands. It makes sense and seems to work.
But please, never "drop the hammer" on your cold Harley motor and never red-line it until fully warm. By "fully warm" I mean that the oil, all of it, engine, gearbox and primary are up to operating temperature. This usually requires about 12 miles at 65 mph. Warm oil is a reliable sign that all the parts are well lubed and that all clearances are within the tolerances of what Harley-Davidson intended.
So, I recommend that you ride your bike moderately just as soon as it is safe to do so. If the engine warms enough to reliably respond to the throttle, ride.
 

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Cabo Wabo '06
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Warm up

Ofnaman1995 said:
For those of you are in as cold of a climate as I am, you may find this article by Joe Minton /American Rider magazine October 24, 2005 an interesting read. After having my bike in storage for the past month, I have a bad itch to go for a ride despite the cold.

Engine warm-up is important and is a good idea that we all know something about the matter. Safety is the most important reason to warm an engine before riding. Most stock engines tend to lack power and deliver uncertain throttle response until they have run for at least a few minutes. In fact, some engines will stop running altogether if the throttle is quickly and fully opened immediately after they are started. If that were to happen in front or someone running a stop sign with their SUV, well.... This kind of scenario, by the way, is the main reason manufacturers often recommend long pre-ride warm-ups.
Many of the motor parts inside your Harley engine do not fit and work together well until they are at or near normal operating temperatures. I think the best example is the cylinder-and-head stack. Evo, Sportster, and Twin Cam engines have aluminum cylinders, heads and rocker boxes. However, the studs that hold those parts together are steel. The difference in the temperature-related expansion rate between aluminum and steel is about 10 to one. Thus, the head gaskets are squeezed much tighter after the motor is hot. Early Evos would often blow head gaskets if they were given full throttle before the cylinders and heads were warm. The earlier Shovelheads and Iron Sportsters did not have this problem and, at least in this one respect, were superior designs.
Lets look at our street Harley motors and how we use them. Most of the time we are asking them to produce less than 15 Horsepower when traveling at steady speeds. About 10 horsepower are needed to push a Sportster down a flat, windless road at 60 mph. An FXD or bare Softail needs 11 or so and a full touring rig about 13. This isn't much of a load for an engine capable of producing 60 peak horsepower.
I can assure you that Harley-Davidson has spent many hours and miles refining the piston, ring, valve guide and other dimensions to serve this standard load. They have also had to allow for the occasional extremes which include "seeing what she'll do" and the stresses of abusive warm-up.
The extra ring end-gap needed to ensure there is no binding during long full throttle runs allows blow-by when the gap is wider, as it is when the engine is cold. The ring end-gap must be large enough for a hot engine and is likely too large in a cold engine. There are other such compromises like piston skirt-to-cylinder clearance and cylinder-head torque. If you were to make sure your Harley motor were completely warm before using full throttle to get up to 100 mph, you could run the piston clearance within a half-thousandths of an inch of the cylinder walls instead of the standard two-thou (or so). Harley must certainly assume that you might not do that and fits pistons accordingly.
So, what is a person to do to properly warm-up the engine? Basically, give the motor a chance to swell up and get its clearances together. The bit of extra piston/cylinder clearance or piston ring end gap won't matter if you keep the loads and rpm moderate during warm-up. The lower clamping pressure holding the heads in close proximity to the cylinders aren't so important at half-throttle.
Why not just let the engine idle until it is warm? This is important. A cold engine generally needs the choke to run at all. Chokes are relatively crude devices and dump too much fuel into the engine, more than it needs. This extra fuel washes oil off cylinder walls, finds it’s way past loose pistons (and ring gaps) and down into the oil. Other byproducts of combustion find their way into the crankcase and engine oil as well. These include: water, acids and carbon particles.

The best way to minimize all this contamination is to warm the engine as quickly as is reasonably possible. "Reasonably possible" includes placing a load on the engine by actually riding the bike. One or two horsepower are needed to idle an engine, but it takes 10 or so to go down the road. More horsepower develops more heat; hence, the heat from the 10 warms the motor faster, reducing corrosive oil and engine contamination.
If you keep revs below halfway to redline and the throttle below one-half, you'll have no trouble with blow-by or overstressing cold and still loose parts. Long ago, before emissions standards and too many lawyers with time on their hands, General Motors learned that engines lasted longer if they were warmed by driving the car. I have ridden with that recommendation in mind for 40-plus years and preached it to thousands. It makes sense and seems to work.
But please, never "drop the hammer" on your cold Harley motor and never red-line it until fully warm. By "fully warm" I mean that the oil, all of it, engine, gearbox and primary are up to operating temperature. This usually requires about 12 miles at 65 mph. Warm oil is a reliable sign that all the parts are well lubed and that all clearances are within the tolerances of what Harley-Davidson intended.
So, I recommend that you ride your bike moderately just as soon as it is safe to do so. If the engine warms enough to reliably respond to the throttle, ride.

Good read. I've got fairly new 95" forged high comp pistons in the new build. In this colder weather I let her warm a few minutes before riding. Warmer weather will bring quicker ride times. Too quick is not good, and too much time isn't either. Listen to the motor. It'll tell you when it's ok to push it. Conservative riding for a bit is a good way to get there.
 

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Since I live in a neighborhood, I always start my scoots in my garage first. #1: I like to make sure they are gonna start. #2: I live on a hill and if I push them out, I'll never be able to push them back in. #3: One of my pals has a Kaw cruiser. He didn't let it warm up, pulled into the street, it stalled, he dropped it onto his leg, broke the socket to his knee. 6 months off of work and he may never ride again.
 

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8-Ball said:
Ofnaman.... great article and thanks for posting. I've wondered about this topic often...
Tell the truth 8-Ball. The marvelous motor head you are and all. You knew this stuff all along didn't you...
 

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With any fuel injected motor you should be able to start it and get on and ride it almost immediately. No more than a few minutes of warm up max before it can be ridden. Just ride it as stated until it warms up, no full throttle for about 10 miles.
Both my bikes have carbs and I usually only let them idle long enough to put on my coat, gloves and helmet before I ride off. Letting them idle with the enricher out is a sure way to foul a plug. I usually have the enricher all the way in about 1 mile down the road.
 

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8-Ball said:
yeah... right... I'm working on it though... you should see my rear caliper...
LMAO, good one 8-Ball. You know more than you think but only enough to make you dangerous at times. Ride safe friend.
You live in So-CA, is warming up a bike really a problem? Add to that fuel injection and a good doof clena fuel curve, and you should be able to push that button on the right handlebar control and ride off.
 

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LittleBear said:
LMAO, good one 8-Ball. You know more than you think but only enough to make you dangerous at times. Ride safe friend.
You live in So-CA, is warming up a bike really a problem? Add to that fuel injection and a good doof clena fuel curve, and you should be able to push that button on the right handlebar control and ride off.
It got down to 29º last week... so it gets cold in the morning and the mountains get damned cold... got me the doof clena fuel curve installed by Steve himself... did it with a sledge...

Here is a question.

I'm running AMsoil 60wt racing oil. How does the use of this oil affect the warm up time...
 

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8-Ball said:
It got down to 29º last week... so it gets cold in the morning and the mountains get damned cold... got me the doof clena fuel curve installed by Steve himself... did it with a sledge...

Here is a question.

I'm running AMsoil 60wt racing oil. How does the use of this oil affect the warm up time...
You riding a Shovelhead? Change to 20w-50 and get on with life. Even crossing the Mohave in 107 degree heat the 20w-50 will work just fine.
The 60w is not good for cold starts and may take longer to reach operating temp.
If you lived in parts of AZ, then 60w may be justified, but not where you live and do most of your riding.
 

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LittleBear said:
You riding a Shovelhead? Change to 20w-50 and get on with life. Even crossing the Mohave in 107 degree heat the 20w-50 will work just fine.
The 60w is not good for cold starts and may take longer to reach operating temp.
If you lived in parts of AZ, then 60w may be justified, but not where you live and do most of your riding.
Its what Steve recommended... and it sounds so much faster...

His argument was that 20-50 suds up and loses its lubricosity... and once the engine is to temperature, the 60 works better.

Maybe I could stencil "Racing" on some 20-50...

Can I mix 20-50 with 60... does that give me like 20-56.43?
 

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Steve lives where 60w make more sense to me. He can ride down the hill to 100* heat almost 9 months out of the year. My brother lives in the desert and rides a Shovelhead so 60w makes sense to him, but you ride a TC98. You may want to email George on this one, but in anything under 100*, and based on your average riding temp, I would think 20w-50 would be best. Since you are running syn oil, breakdown is not an issue with the heat and on any cross country tour, the average temp during the day rarely exceeds 100*, even in Nevada or Utah.
Just my opinion of course and Steve knows a lot more than me.
I use 15w-50 Mobil1 here in TX and have never had any oil issues, even on our hot days. Do what you fell is right for you, not based on what I say, but I am right. LOL.
And before anybody quotes the H-D manual, I know what it says about oil and temperature ranges.
Oh and sorry for thread drift, damm oil threads anyway, follow the warming techniques mentioned above and your motor will be happy.
 

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Don't let your engine warm up for too long, overheating could be a problem....



-darrell
 

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Quicker warm-ups

A "factory lean" bike warms a bit slower than one properly jetted and with the correct mixture which is another reason to rejet your carb.
 

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Every time that I read about warming up your engine I think or John Muir's advice in the servicing VWs for the complete idiot. He would start up the car, then roll a cigerette, that was his warmup time. He rolled his own and smoked. I think that if he didn't smoke, he would have just started off slow until the engine was warm.
 

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heads warm?

:thumbsup: i have heard through the harley shop after just buying an 883 r that to let it fully warm up is great and to cheack if it is fully warm press your knuckles against the heads if you feel a bit of heat then it is safe to ride. Thats what ive been told
 

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Warm Up

There was an excellent article in American Iron by Donny Peterson some months ago, that dealt with all sorts of properties of oils. The main info I got out of it was that all 20-50w oil was made for air cooled engines. He told about the various additives in oils. Made for some good reading.
 
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