Warming up the Engine

[TJ NSR]

The importance of Warming-up

The worst time for an engine is cold running. The oil’s too thick to pump around quickly and can either:

1. cavitate (form a vacuum) which damages the pump:
2. allow air entertainment (even a brief dose of air severely damages some bearings)
3. or builds up the pressure to burst things.

Cold oil takes time to reach high-load parts (valve trains have the greatest contact stress, wearing cams and followers). Meanwhile, excessive piston and crank clearances over-oil the bores and the rings lose control (why 2-strokes splutter and smoke from cold).

Letting the bike warm up before getting on to it is always good (ie while putting leathers on let bike run), this way engine starts to get warmer then when riding it ride it at low revs for a few minutes as the oil still hasnt reached the whole engine.

Fastest warm-up is on a light load at 2000-3000 rpm through the gears.


edited by tj

[craigT19]

Also try this.....

Bikes that are parked on side stands drain all the oil to one side of the engine, so stand the thing up for a few secs.

And this...

Engage the kill switch and hit the started button...the engine wont start but some will still turn over, this will pump the oil all round the engine ready for when you start.
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Bikes owned :- 2001 nsr125, 1999 zx6r, 2006 yzf-r1, 2009 xmax 250, 2012 yzf-r1, 2015 MT-07
Current bike : - 2016 MT-10
BCF member pops. sadly missed 1945-2003

[muppet_ninja]

what you on about !! NSRs are two stroke (obviously) you don't have to worry about oil

[Scooby]

This thread is not just for 2 strokes you know, so Craig's right, cos those that own 4 strokes can use this method.
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A big enough hammer fixes anything!

[McJamweasel]

Wouldnt that still be a good idea on a stroker to get oil round the box?
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BCF: Be yourself, just don't be an arse.

[Scooby]

I didn't think the oil pump worked until the engine was started on a 2 stroke? Maybe I am wrong?
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A big enough hammer fixes anything!

[cagiva gezzer]

Warming two strokes.

They should be allowed to idle until the bike can pull away without spluttering and stalling. Usually around 2 -3 min, or enough time to get suited and booted.

They shouldnt be thrashed untill they are upto normal temp and have stopped smoking loads. This is to allow the cooling system to be warmed up, mechanical parts to expand and take up slap, oil to reach its optium operating range.

Running on the stand. This can cause probs and Aprillia blamed my friends main bearing probs on the fact that he let it warm up on the stand for too long.

The gearbox oil will lube from the start, its just that it does it better when warm. The oil injector pump will work from cold, its just the oil wont lube the engine.

Four strokes. The engines should only be run on idle for the min time poss to allow some oil to circulate and warm slighly. If left for too long, combustion doesnt happen very efficiently and acids can build up in the oil, leading to poor oil performance (so im told)

Just be sensible and remember that casterol (i think) advert with the crying engines.
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"because one stroke isnt enough and four strokes waste two"

[matthewgt]

i have a problem, wondering if someone could help? i own a nsr125r 2002, bought november. i have always warmed up thusly: let it on choke for a minute, drive in low revs, changing up in low revs until bout 20mph, then changing into 1st . it gets rid of the smoke, but im reconing its causing lots of damage. thanks for any help.
matt

[McJamweasel]

It will be because 20mph in first will be almost redlining it. Just carry on using low revs (say 5~6k) until it is properly warmed up.
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BCF: Be yourself, just don't be an arse.

[Kickstart@Work]

Hi

Petrol is a very good degreasant. Running with the choke on results in loads of extra petrol floating round which will do a good job of washing the oil from the bearings / bores.

My view is start the bike up and ride off as soon as they engine will safely pull, and knock the choke off as soon as you can.

This will vary from bike to bike. With my RS125 (for example) I can generally start it without the choke and ride off immediatly. My 1200 Bandit will not accept running on the choke for more than about 200 yards, and if you try it / forget it will stall the first time you slow down and pull the clutch in.

Just do not thrash it until it is up to full temperature. Rough rule of thumb is keep it under half the red line until fully warm.

Oil generally gets round a 4 stroke engine quite quickly (couple of seconds), but in extreeme conditions (VERY cold) it has been found to take up to about 90 seconds before it reaches the top end. However the oil will probably not reach full operating temperature until you have done 10~20 miles.

All the best

Keith
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[stevo as b4]

On my zx6 i have a digi water temp guage, and i know this is not any indication of oil temp, but it doesnt register a reading until 40c, so i wait until it reaches about 45c before i ride off usually. I agree with keith that warming up a four stroke especially a kawasaki! on full choke is the worst thing you can do, and its probably the fastest way to wear out you motor! I use choke just for starting, and in hot weather it will start from cold without the choke.

[Danny]

Any tips for warming up an air cooled bike? My GPz550 doesn't have any temp gauges, so I never really know when it's warmed up.

[stevo as b4]

Aircooled bikes generally should warm up faster than a liquid cooled motor would, so i would say that about 2min of running on the drive before you ride off would be enough, or just wait until you can pull away without choke, and without the bike spluttering. I know that below 40deg c my zx6r splutters slightly, and if your in busy traffic, then thats the last thing you'd want. The worst thing you can do on a fourstroke is to use too much choke, i.e. leaving the bike running at 3-4000rpm on full choke for 5min, every day would help wear your motor out rapidly, not to mention the amount of fuel you'd waste.

[Scotty]

On the NSR i never klet it warm up. as soon as it can go i;m on it. i just keep it below half redline till it warms up.
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Regards
Scott

[Claud 14.7 to 1]

My bike likes choke pretty much in all weathers, except really hot.
I have always needed choke bar one time this year. I only use a bit of choke, so it starts and idles at 1500 rpm.

It will start off choke, but needs part choke to stay alive...

All bikes are different.

Just remember to ride low rpm, even after your bike has warmed up (standing) for a while.

[andrew]

I would have thought your bike was idling to low if you need the choke all the time?

[Claud 14.7 to 1]

[Claud 14.7 to 1]

My point was that all bikes are different, and need different ways of starting.

Maybey my bike is just showing its age.

Or maybey its "showing" me the importance of warming your bike up.

[fazed]

and what you got your cbr400 idling at when warm 1700rpm? , shouldn`t really stall if its idling at 1000 odd when cold

[priller]

[JonB]

Well my two stroke is pathetic! It doesn't even idle when the engine is turned on, I have to warm it up by gently pulling the throttle and gently letting it back for quite a while, but the amount of smoke that comes out at the start is unbelieveable!
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Be careful whose advice you buy, but, be patient with those who supply it. Advice is a form of nostalgia, dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it?s worth.

[JonB]

I started using Castrol TTS oil from last Friday and I have found that the enigine warms up much quicker isntead of the Castrol Scoo-ter stuff.
____________________
Be careful whose advice you buy, but, be patient with those who supply it. Advice is a form of nostalgia, dispensing it is a way of fishing the past from the disposal, wiping it off, painting over the ugly parts and recycling it for more than it?s worth.

[fuzz]

I don't know if it's the same for all bikes or just 2 strokes or just the NSR, but until it's warmed up, the engine really does not sound happy as it's approaching 6k revs. Why would you want to push it further when it's telling you it doesn't want to?

I always start it up with the choke on until the revs drop below 3k, off with the choke and keep it below 6k until it sounds much happier!

[Craggles]

With my 4 Stoke GN125 I tend to have the choke half on when I start it on the drive, idles at around 1 - 1200 when cold.

I tend to open the throttle slightly when idling to keep the revs at about 1.5k, take the choke off, give a few more revs then a slow journey down my road (I couldn't go above about 20-25 safely even if I wasn't trying to warm up!) I tend to be waiting at traffic lights at the bottom of my road leading turning onto a 40mph road within about 6-7 minutes, need to blip the throttle once or twice there to make sure the engine dosn't die on me.

The bike tends to stall when I knock down into First to pull off, and the engine can die sometimes - I just put this down to my technique - Dad says he dosn't have a problem.

I feel I can't just start the engine (choke or no choke) and leave the bike to run to warm up while I put my gear on. I need to be on top of it, keeping some revs there.

[fuzz]