How to warm up bike engine?

[SMOKEU]

Many people say they warm up their (4 stroke) bike engine from a cold start by idling it for several minutes, because it's bad to put unnecessary load on a cold engine. Fair enough.

While other people say you should ride ASAP without letting it idle for a few minutes, because that way it warms up faster, and the faster it warms up, the less wear happens on the engine.

What are your thoughts on this?

[DarkLord]

I hear that letting it idle for a long time is not good for it as the oil is not getting through all of the moving parts because the bike is not moving, so it's best to jump straight on and just take it easy for a bit.

I usually ride with the choke on for a few ks until the engine has warmed up enough.

[Owl]

Mine is normally running for about a minute while I put my helmet and gloves on. If not, I'll just start it and ride, but I take it quietly until warm.

[Grumph]

The critical point when warming a fourstroke is not to put excessive load on the cams & followers as these are usually the last places to get properly lubed.
The rpm point where inertia loads versus spring loadings usually cross over is around 2000 to 3000 rpm so holding a motor around this rpm until warm - if it will do this - is usually satisfactory. Things like Manx Nortons don't want to hold a steady rpm this low so often have to be blipped to keep running.
Personally I fire a motor & wind up the idle to around 2 and walk away for a few minutes. A temperature gauge is very useful but obviously not always fitted.
And once you've got your air cooled fourstroke warm, try & keep it warm. Don't leave it out in a cold wind or you'll have to warm it again. The thick bike covers that used to be seen on Manxes and 7R's etc were a damm good idea to keep the Castor base "motor honey" at least liquid.

[cheshirecat]

I was told by someone running racing courses at Silverstone re Honda VF400's to ride them gently until temp guage moved and not warm up too much before hand.
Have done this with all my bikes since, especially London despatching with a VF500 which did 80 thousand miles with basic maintenance.

[Ghost_Bullet]

I just start and ride, its a Guzzi, so not only oil to warm up in the engine, but gearbox and rear transmission, the only way to warm the 2nd two is to move. I dont see much point is just standing around waiting.

[sil3nt]

Get on and ride. Just keep the RPM below what a certain point for awhile.

http://faq.ninja250.org/wiki/Warming_up_your_engine

[NZsarge]

Normally start the bike, wait until the first bar show up on the LCD guage then ride it really easy until I hit the main drag to town which is about 3k's away.

[Headbanger]

Hold the throttle on full until engine starts missing.

At this time the optimum temp has been achieved, Select a gear and move off, using the clutch is optional.

[onearmedbandit]

Fi bikes take care of it all for you. But I'll start mine, put glove and helmet on, then ride off without giving it any grief. once the temp is up around 40c I will then treat it like I stole it.

[SS90]

Hold the throttle on full until engine starts missing.

At this time the optimum temp has been achieved, Select a gear and move off, using the clutch is optional.

That's right....... It's what Jesus would do.

[Robtharalson]

Gordon Jennings educated me on this subject -- Above -2C or so fire it up and start riding it as soon as it will take some throttle without falling on it's face. Why? Simple: One of the normal byproducts of internal combustion is water in vaporous form. When a motor is started from cold the cylinder liners are at ambient temperature, and due to the negative pressure during the intake stroke that vapor will condense onto any surface that is below the dew point, which increases as relative pressure drops. The end result of this is the water condensed onto the cylinder liner will displace oil normally deposited in the microgrooves of the crosshatch, depriving the rings of the lubrication they so desperately need. Add to that the rich mixture with the choke / enrichener / whatever they call it activated and you have a recipe for excessive wear in the form of linear scars on the liner and rings with matching patterns.

Concerns:
-- Inadequate oil to the nether regions of the engine, especially the cams / followers.
Unless you are on certain models of Ducati the top end is well fed with oil within 2 to 3 seconds of starting. It has to be to insure longevity of all the plain bearings the cam(s) ride in and the follower faces. I know this to be the case from experiments I participated in where windows were fitted in cam covers to visually monitor (with high speed cameras) oil scavenge flow patterns around the cam mechanisms on a variety of pressure lubricated motorcycle engines. Usually there was oil appearing around the cam bearings and spraying across the follower faces before the engine was actually running, and the average full flow time was under three seconds. No problem there.

-- Cold pistons can get too hot too fast and expand in their still warming up bores, either seizing or more likely scrubbing against the cylinder wall, eventually damaging the bores and pistons.
Modern (post early '70's) hypereutectic (high silicon) aluminum pistons are very heat stable -- on average Honda specifies a cold piston to cylinder clearance of 0.02mm, or 0.0008", meaning the piston doesn't expand very much at all or it wouldn't survive its first start and heat cycle. No problem there either.

-- Transmission shafts and gears need time to get fully lubricated.
One fact must be remembered here: these parts are not sponges that need to be thoroughly filled with oil before it becomes available for lubrication. Again, studies confirm pressure lubricated transmissions, despite sucking hind tit oil wise, are fully lubricated within 5 seconds of starting the engine. Once the oil is there it is as lubed as it will ever be, or need to be. The only part that doesn't get a nearly immediate bath of oil is the clutch plates, and since you are going to be taking it easy for the first few klicks, that's not really an issue either.

Below -2C it is advised that the motor be run at an elevated speed for one minute, say 2,000 to 2,500 rpm, to give the oil time to warm from glop to useful. Past that go for it (Uh, gently remember?)

Observable reality (my not warming up a motor before riding off for the last 35 years, and no oil related failures or even ring jobs despite putting well over 150,000 miles on several bikes) would seem to confirm the "Fire it up and go, but take it easy on your cold engine and tires." procedure is a good one. Everyone else, of course, is free to do as they wish.

Rob

[bogan]

That's right....... It's what Jesus would do.

and its only that first time, after that he just leaves em on high idle when not riding, I expect his garage will be a symphony in awesome

[emaN]

Cheers for that info Rob...

I read an article back in the UK a few yrs ago which addressed this question.

Outcome was: run the bike for as long as it takes to put your bash hat & gloves on & then ride her...gently at first.

So I've done that with good results, but I wait 'til she gets up to 65-70C before sending that needle swinging towards the red tho'...

[release_the_bees]

Normally, I start the bike up and then put on all my gear while the bike is warming up. The GS500 is very cold-blooded and needs a good warm up before it will run smoothly, so the routine is to let it idle for 5-10 minutes before setting off. Even with this warm up routine, I still wait a good 10-15 minutes before really opening a bike up.