Modern Vespa

When I warm up the engine, if I leave it to idle for a while, will it drain the battery? If I drive it around does it recharge?

Please don't. Just start it and ride. There is zero need to 'warm up', and it's the worst thing you can do as the engine wears the most when it's cold, and idling takes ages to get the engine hot.


If you do let it idle, it shouldn't drain the battery in a healthy system, but it won't charge it much, if at all, so it won't replace the energy used in starting the bike.

Get your gear on, start the engine, ride off.

The engine actually "warms up" much more quickly if you just ride off at a modest speed. Avoid hard acceleration for the first few minutes and you will have achieved your objective.

What about carbed scooters then? Fuel injection has made what you describe possible to an extent, well I should say it makes getting the engine up to operating temp less of a faff. Don't forget that loading a cold engine accelerates wear almost the same as idling it to get up to temp, so the difference is a wash.

I would think that both are fine given the technology we enjoy now with modern synthetic oil. It's just that, well for one thing you really kinda do need to warm a carbed bike up. Can't just go off a ridin' with it boggin' and stuttering. Basically you would be trying to ride it choked up which is not the thing to do. With an FI bike, it has better manners cold but the stiffness in the engine can still be felt.

The sure thing is to rig up a preoiling system such as what race cars with dry sumps use. But that would be going way too far.

The auto-chokes on Piaggio engines switch off completely after about 30 seconds. Just ride off - if your engine stutters then check those valve clearances!

My brand new Keihin CV18's cold start enrichment does not shut off after 30 seconds. It settles down after more like 3 minutes. The original Keihin CV18 did the same thing. It's actually cold where I live, not merely chilly. So I really do have to let it warm up. No way around it. Can't ride off while it's choking, because that is no bueno. The valves are adjusted precisely.

I was under the impression that if you're deep in do do, it would be warm.

Even with a carb'd bike you can lightly feather the throttle enough to engage the clutch. Hold that for 45 sec. and your golden.

LOL the steaming pile.

I'll go ahead and let mine warm as it wants LOL

I ride a 72 year old carbed motorcycle and I never warm it up. I start it, climb on and ride off gently. On a 30F morning it will take 3 or 4 miles to get warm enough that no enricher is needed (it's manually controlled). If the temp is 50F, no enricher is needed after just 1 mile.

-Craig

I have both a carbed and FI modern Vespa. The local dealer, who has prepared engines for racers at the IOM TT, agrees that you start them and ride them. Modern metals, production techniques/tolerances and oils mean you do the least harm that way.

My LX bogs & sputters if I do that. So I don't do that.

What's the 72 year old bike?

Look over on the left where caschnd1 lists his rides. (it is a '49 Harley FL)

Is yours a 2T or 4T? If the 4-stroke then check those valves...

So you're saying powering off-the-line one block from my apartment is bad for the engine? 🤔

Ahh, duh

Definitely start the engine and ride off as soon as you can as Jimc and others are saying. Don't leave the motor idling from a cold start as that is very bad for it. You are simply extending the period of time when the engine suffers it's worst amount of engine wear if you do that. The motor warms up faster if ridden away gently without suffering the same amount of wear as if it was left idling. All the evidence shows this to be the case.

Nearly all total engine wear in an engines life (between 93-97%) takes place in the first 5-7mins of riding whilst the engine is very cold. The exact amount of wear is determined by the design of, and type of engine you are talking about and the way you treat the engine at this crucial time. Whether it's liquid or air cooled also affects the engine wear, with liquid cooled engines suffering less wear at every stage of it's running cycle. The type and grade of oil you use also has a huge effect on wear too. You want an oil that has high oil flow (a thin oil) with high oil film strength (OFS) and the best cling factor. Motorcycle oils of the correct grade will give you this.

Designing and testing engines and being a tech for a living revealed between 93-97% of all engine wear happens in those first few minutes I mention above, with almost zero engine wear happening once the engine is hot, even very very hot under arduous conditions! In most circumstances it is unnecessary to ever change from the manufacturers recommended grade of oil. Notice I don't say "weight" as that is not a correct engineering term as weight of the oil has nothing to do with it.

So just start her up and get going as soon as you can. If you bike has a choke and it's not able to pull cleanly from cold after a 30second fast idle I'd check her over to see if there is a problem with the cold start device as most choked bikes will run ok even from very cold conditions after the briefest of idles. It might be that if it won't run correctly from cold you have an air leak or worn carb.

OK OK! I'll try doing what everyone suggests. LOL

In the dead of Winter in these parts, I give Melody about thirty seconds after starting while I put cinch my helmet strap and slip the gloves on. That's the absolute most I think the bike would need under those circumstances. Any other time of the year, I just punch the starter, hop on and take off: speed limit is 25mph if I turn right, 35 if I turn left (different townships, y'know), so I'm not exactly doing the hooligan thing for a few miles anyway.

To answer the original question, put a voltmeter on the battery when idling, and see what it says. If it is showing 12.5 or less, it is not charging at that RPM, and you are draining the battery, albeit slowly. Much more voltage than that, it is charging, and in that regard you can let it idle as long as you want.

Generally the 'warm-up' discussion is also a function of air temp, and oil being used. Most manuals show a range of oil viscosities to cover different operating temps. If you are using one of the 'thicker' oils on a cold morning, letting the engine idle for a bit before loading it heavily isn't a bad idea. And even then, best not to employ full throttle for a few blocks so the engine has a chance to gently get up to operating temp. If you are using a lighter oil, or a synthetic, less of a concern.

FWIW, light aircraft engines require extensive warmup, in most cases, in order to get the oil temp up, before using full power for takeoff. And on cold days, they employ pre-heaters to get the engine parts warmed up, before attempting to start it. Take from that what you will.

Those engines also have to undergo far more thorough maintenance and parts replacement schedules to check for wear and tear. Motorcycles don't have to go full throttle for some minutes right at the start of the journey. Apples and oranges.

Engines are engines. Usually aircraft use nearly max power for takeoff, so important not to go from a cold engine to full power. Similarly, small scooter engines are often putting out max power in some traffic situations, so best not to start it up and go, if you'll need to pin the throttle to keep from getting run over.

The idea is to let the parts get warmed up to some degree so they've expanded to the proper fit, and the oil is warmed up enough to be reaching all the parts of the engine it needs to. If you do a lot of cold-weather riding, probably best to use a synthetic oil, of the lower allowed viscosity, to assist in that.

Clearly aircraft engines are much larger physically, so the 'expand to fit' issue is greater. Most are air/oil cooled, so warming the oil spreads the heat to parts of the engine that are away from the combustion process. Aircraft engines are also pretty absurdly expensive, so, to achieve maximum useful life, they get 'babied' a bit. And engine reliability is of paramount importance, so procedures are set to avoid possible problems.

Use the proper oil. On very cold mornings, start it up, let it idle while you are putting on your gloves and helmet, go easy on the throttle for the first couple of blocks, and it should be fine.

-https://www.youtube.com/watch?v=RWGngqesrrI-

From what I know (I also specialize in aircraft mechanics on piston engines) the habit of warming up the engine dates back to epochs that are lost in the night of ancient times ... (I like it, it's poetic).
My grandfather told me that in the cold winter mornings of the 1930s he put a bowl with glowing embers under his Moto Guzzi S 500 but only to warm the engine casing because the Guzzi bikes of that time had dry sump lubrication (like many American ). This made starting easier ...
Remember they were also air-cooled and not like our modern liquid-cooled scooters; they are warmed in this way because the engine immediately goes to operating temperature and the engine oil sump is very small and therefore the oil thins immediately.
Another determining factor is the engine oil pump, it is gear or trochoidal and therefore with a high flow rate and the oil is transported to every corner of the engine quickly and recirculates very quickly. In short .... no downtime to fill, everything is immediately functional.
Jimding... how beautiful were the star engines of the old planes ...

And indeed aircraft engines are quite different to our mc engines. They rev very low and idle low. The compression ratios are very low and clearances quite large in many areas of the engine when it's cold so they are lightly stressed even when cold. Most light aircraft with piston engines are air cooled so the pistons and barrels warm quickly, and as jimding says need to have the engine and oil warmed up first before setting out to take off. This makes sure they can achieve full power without excessive engine wear. I learned to fly on a Cessna 206 with the Lycoming 6 cylinder 315hp engine. It didn't take long to reach warm up. But ac engines are set up very differently to our bikes and ac engines don't suffer the same sort of engine wear under idling as our bike engines do. I transitioned to turbine engined planes after the Cessna and the beauty of the turbine engines is they do not require even 30 seconds warm up. They are full temperature straight away.

It should be added that some motorcycle engines have a without cast iron barrel cylinder but with a chromed / treated surface. They heat up very quickly, my 155 is like that.

Here's a question about letting the engine run, but not in the context of a cold start. I play a game where I drive to different locations, pull out my phone and may be there 30 seconds or maybe up to 5 minutes. If it's 30 seconds, fine. I'll just idle. But, at what point should I turn the engine off? Is idling 2 minutes worse than turning the engine off for 2 minutes?

With idling the coolant is moving. Sometimes the fans turn on. I've noticed they turn on more often on my HPE than they did on my older 2007 GTS. In my mind I can argue this one either way. I just don't know if one way is better than the other.

Personally I'd turn the engine off each time. However, idling while hot doesn't stress the engine nearly as much - as long as that fan does come on!

It depends on the climate, on the liquid cooled Vespa the fans (there are two?) Almost always turn ... The position of the two radiators is not optimal, I wonder when they will move it behind as on other Piaggio engines.

Best answer yet 🐝

DiaSiL cylinder .

My scoot resembles a low flying aircraft as I filter between slow moving traffic, so I guess the warm up technique is working.

I open the garage door, put on the helmet, start the scooter (07 BV250 with a carb), roll out of the garage with it idling, push the door closer, pull on the gloves, wait until the door is closed all the way, and then ride off at a leisurely speed. My neighbors like the quiet, I like the reassurance that the door is closed, and by the time I get to the street with traffic the scooter is warmed up and ready to go.

Best to turn it off if it's 5 or so minutes. If left idling, the fan (there is one) shouldn't come on for several minutes (10mins) in an ambient temp of around 22c. If it's a much hotter climate then the fan may come on sooner. Mine idles at full warmed up temperature for 10 mins before the fan comes on in 23-24c ambient temp. If your fan is coming on very soon it might be you have an air bubble in the cooling system or your coolant is old and needs changing.

I'm pretty sure get in it and go wasn't a thing until the Oil Embargo. Prior to that, all the manufacturers said to warm it up. Then the EPA got involved and the story changed to "no need to warm it up," even though the models that previously could use a little warm up were the same ones that suddenly didn't need it. The Government first said not to warm it up, and the manufacturers repeated it. Take from that what you will, and keep in mind that advice you are given by manufacturers is often in their best interest, not yours, or for reasons other than what's really best for your vehicle. Low viscosity oil improves CAFE averages. Warming it up uses more fuel. I warm it up for about thirty seconds to a minute most days, more if it's below freezing.

To be clear Motovista, the advise, certainly over here and in europe, to start the engine and avoid unnecessary idling and ride off gently almost straight away was manufacturer led. We told the government it produced less pollution but was also best for the owner as the most engine wear occurs after a cold start. and was increased by idling. Warming it up just made the wear factor much worse, wastes more fuel, breaks down your oil sooner and is generally much worse for the environment. Any other coincidences are just that! Governments make the policy environmental or otherwise. Manufacturers and engine design engineers tell the government what is possible and how best to get the most from the policy.

In the States you have long been on the drag regarding just about everything relating to motoring. Over here it's long been that you start her up and drive away almost straight away. Only on very very cold mornings with carbed bikes and cars did you need to let it run for a minute of two before moving off. Once fuel injection came in everything changed as it does away with the need to warm anything up. I'm thinking that was around the time of the oil embargo for many manufacturers, it certainly was over here.

"Over there" it is not uncommon to see taxi drivers manually push their cars to the front of the line as one gets a fare. Due to the difference in the price of gas compared to the price of a car or repair, different systems come into play. We have been much more aggressive over here, from the beginning, about automotive emissions.
Instead of basing your response to what you think you remember from the mid 1970s, when this first came into practice, go back and look at who said what first, and where.
Basically there are two theories at work here, one is that you will warm the car up quicker, and lower emissions, by driving off, and the other that you will cause less stress to the internal components if you let them gently come up to temperature. Once they take the bikes out of the truck and get ready to do warm up laps, do factory racers hit the starter and run a few laps, or do they let the bike warm up for a few minutes? This will probably give you the answer as to what's really best for an engine, because they have pretty smart people telling them what's best for their bikes.

Yes indeed I have Motovista. I was actually one of those "smart" people on the design and engineering side for many many years. I kinda helped write the engineering book on it. None of this "warm it up and drive off asap" for road engines is new. It's been about for decades and decades. There is no longer a debate about whether it is the best thing to do as it has been long proven to be the very best way to treat an engine. This is because we understand exactly what happens when an engine is started and left to idle for several minutes whilst cold. We understand how much *water is produced and passed into the oil during idling from cold, and we understand how much acid that can produce, how much wear takes place while idling etc etc. There is a lot that goes on. Emissions are at their greatest with the fuel system on full advance causing oil wash down from the cylinders into the oil too further degrading the oil. So one of your theories is disproved and has been so for many years.

Your analogy with racing engines is not a fair comparison.Proper racing engines are completely different in the way they are set up and require frequent stripping down for maintenance and overhaul. Road engines don't. Although it's not been my mainstream work (I've predominantly designed and developed road engines), I've also designed and developed racing engines for both clubman cars and bikes in the last 40 years. A warm up lap/s is mandatory to get the pistons and rings to swell into the bores. These engines require big clearances for pistons and ring gaps so they don't seize with prolonged high engine revs under high loadings. You cannot get that heat in by idling a race engine since the clearances for pistons and rings are too large to allow full power right away without the motor being fully warmed up on the warm up lap/s. And you don't spare the horses either on the warm up lap/s. You need to get that heat into the engine internals fast. Idling after warm up is ok but not before.

*Note: for every gallon of gas burned one gallon of water is produced. When the motor is cold approximately 8-12% of the initial combustion process goes into the oil when cold and with the engine idling. Exactly how much blowby is produced depends on the condition of the engine and it's type. This water is mixed with the unburned fuel and produces acid which eats your motor from the inside if you don't get the oil up to temperature and keep it there for several miles to evaporate it out. Less water and unburned fuel is passed into the oil if the engine is driven off asap after starting because the pistons and rings in particular are under load, getting hot quickly and producing a better gas tight seal. This of course warms up the engine remarkably quickly wasting less fuel in the process and reducing engine wear and also emissions.

I was wondering who designed the cylinder head in the MGA. Remember when they used to put Datsun Roadster heads on them?

You should let the idle level off, especially when it's cold, before gunning it out of the driveway. Once it's level, you are good to go. But aluminum expands a lot faster than the bolts holding your cylinder and head to the crankcase, so it's not a good idea to pin the tach until the entire motor is up to operating temperature.

Unless the engine stalls in front of oncoming traffic... The problem with carb bikes is that if you crack the throttle when they are cold, you can stall them out.

Yeah, never good to pin the throttle with a cold motor. The cylinder head always expands faster than the cylinder block or barrel no matter what metals are used in the block/barrel. But the engine is designed so that if you do pin the throttle out of necessity when the motor is cold, an alloy head on a cast block or even on an alloy block will expand at a set rate and is always going to be fine. That's what gaskets do these days, they allow for sliding and sideways movement between the head and block without leaking.

Chrysler in our country in the 70's had a lot of issues on some of their motors with leaking head gaskets. This was due to them failing to use 'stretch bolts' or 'torque to stretch' studs in their engines with alloy heads. That method of pinning the head down allows for plenty of movement without a leaking head gasket. That's why most engines use that method.

The MGA was well before my time. Not many about now and never worked on one.

I want that book with an autographed dedication, so I can boast of knowing a famous person.