Push start an efi bike
 

Assuming you have a slope, traction and the strength, can you push start a modern, efi bike in the time-honoured 'push, run and jump' way?
I assume if the battery is completely flat then probably not (didn't work on a 660Z for me), but what about if the starter packs up? A less likely scenario I know, but just wondering.

thanks

Chris S

Yes, providing there is enough voltage in the battery to power the electronics. I would say there is no chance with a flat battery.

This also includes the fuel pump.

have jump started mine a couple times when battery was too low to turn over the starter ... but obviously had enough to power the electronics and fuel pump.

If its a packed up starter, then there should be no problem as long as the battery is fine

Depends how far and how long you can push it for. If the battery is flat, I'm not actually sure if you could try and generate enough for the pump and electronics from using the generator while the bike is moving. I think if you got a tow in a high gear, you might just get going.

Obviously getting a tow on a bike is risky but there are 'safer ways' to do it.

NEVER tie the rope to the bike. Wrap it around the headstock a few times and hold it with your hand on the bars. That way if things get 'Ropey' (excuse the pun), you can take your hand off the rope and it will unwrap and go free.

If the battery was completely dead I don't think you'd get it going just by solo pushing. If there was just not enough power for the starter motor but you had the warning lights etc then pushing would work - it has for me a few times (but with the help of a hill!).

It does depend what you're pushing though - if you're talking 600 single or similar, then I don't think you have a hope. Even with valve lifters and everything functioning on the engine I've never managed to bump start either of mine solo - the back wheel just locks up as soon as you drop the clutch. You need to add at least one other adult size person (or two kids!), get it moving in gear with the valve lifter in and then let go of that.

I once had a battery fail on me during a trip on a DL650. It could no longer hold the charge, so some mornings, when it was below 0 C, I had to push-start the thing. Was really easy to do so, though, as it always fired on first attempt. But the battery wasn´t completely flat, just partially discharged.

Ta for your experiences. I asked because I seem to recall reading somewhere that push starting an efi, even with a good battery, did not work - as if the engaging/spinning of the starter motor did something essential, electronically. But perhaps it's on certain models and I may have got it wrong.

Just remembered this old jump starting vid from the desert. Not an efi bike, just heavy.

Something in the back of my mind says not to push or tow start vehicles (well, cars at least) with catalytic converters - which applies to most, if not all, Efi vehicles in original form.

I am not sure where the thought came from or the reason, but maybe raw fuel going through, until it fires, is harmful to it.
Or maybe raw fuel confuses the sensors in the exhaust.

Maybe that's what I was thinking - it not advised - you're supposed to 'contact your authorised service centre'.

Perhaps raw fuel explodes in what might be a hot cat and scares the horses...

My BMW Brick outfit with 11.5 V in the battery can be bump started. On a simple system where the only thing lacking is the power to turn the starter it works. If you have a CAN network screaming "low battery call service" into the engine ECU it could be rather different and it will depend on the programming so probably different from bike to bike.

You should not JUMP start an electronic engine, some AA type starters are basically welding sets and not good for ECU's

Andy

I think someone touched on it above. In the majority of cases a flat battery is where there isn't enough current to turn the starter motor enough to start the engine (varies between bikes) BUT the battery isn't already damaged beyond use. If this is case, it is fine to bump-start an EFI bike. I did it to my WR250R the other day with no problem.

This is my understanding of it after doing breakdown work for a few years

The problem with push starting anything that has EFI is that if it has turned over until the battery is flat if it has been injecting fuel that hole time and not firing (damp HT and the ignition has been tracking ) when you come along and dry it out with WD40 or the like and push it or jump start it you then fire the engine up and all the unburnt fuel(and there will be a lot of it )l in the exhaust fires up and you get a bloody great bang and the exhaust box splits wide open
I know this because I’ve done it more than once
Bit Of a tip for both cars and bikes if you think it is flooded pull the fuse for the fuel pump then spin it over to try and dry out the cylinders
If there is lots of power in the battery and the only problem is the fact that the starter in not working then there wouldn’t be a problem with pushing it
But like has been said some of the operating systems for the engine management are getting far too clever for their own good and might stop the engine firing if the starter is not working
After all this I’m glad I still have carbs
Hope that’s all now as clear as Mud

Or Not

Consider the fundamentals; a “fuel injector” is a simple solenoid, a coil of wire surrounding a moving conductor. When a current is passed through the coil, the conductor moves opening the injector. Remove (or reversing) the current closes the injector. No current = no functioning injector.


The term “fuel injector” is a misnomer. It has no power to inject anything. The fuel pump picks up fuel from the tank and pumps it under pressure via the “injectors” which when open, allow fuel into the engine and in an open circuit schema, the excess is returned to the fuel tank. All the Efi bikes I know of use electric fuel pumps. No current = no fuel to the injectors.


Further, an Efi system consists of numerous sensors dotted around the bike such as water temp, MAP, throttle position and the lambda sensor etc., some of which draw current to function but all will require current to feed the signal back to the ECU which itself requires current to function.


However, all is not lost. With the exception of BMWs' GS boxers, all bikes use a simple “magnet excited” coil alternator which as long as it moves i.e. when the bike is “bump started” will produce some current. Depending on the model of your ECU and how it is programmed the loss of any or all sensors (i.e. due to loss of current to the sensor) will cause it to run in “default mode” which will allow the engine to function. Residual fuel pressure may remain in the circuit, especially on closed circuit fuel systems. Whether it is enough to start your bike depends on the design of the system, consult your service manual. KTMs' manuals are very informative and will tell you all you need to know.


With the car like GS boxer consult your manual which will tell you “consult your local BMW authorised service technician”.


To avoid you from sweating like a glass blowers arse bumping your 300kg RTW bike up a sand dune in high summer consider putting a LiFePO4 battery in your kit. It's about the size of a ciggy packet, will hold a full charge for several years and with jump leads will get you out of trouble (don't forget the jump leads!) or simply drop it in place of your dead battery.

Slightly off topic, but I saw a great tip over on advrider for bump starting a big heavy bike.

You need two bikes (one fine and obviously one with a flat battery!), parked back to back on centrestands so that that each rear wheels is off the ground and touching each other. Start the running bike and run to a good speed, which will spin the non running bike's wheel in a forward direction, change up a few gears and hold in the clutch. When enough speed is reached, drop the clutch and hey presto.

Sounds like a faff, but is actually really straightforward. There's a video on youtube showing two KTM adventures doing it, but I'm at work and can't access that site to provide a link.

Not all EFI's are the same. Don't the modern Huskies now have batteryless EFI? The kickstart seem to be back. Would be nice to be able to retrofit on the F series BM.

Love that here’s the link

How to bump start a KTM adventure! - YouTube

Bob

Funny, I was just thinking of that attempted P/Starting video of your from years ago in the desert somewhere!!

Check the kill switch
 

Once spent an hour pushing an XBR outfit through snow trying to bump it. It worked a lot better once the driver set the kill switch to run!

Andy

Love it!
Been there. done that (I guess we all have), but not for an hour!!

Slightly :offtopic:

Could I guess who that might have been? :rofl:

I know it's kind of late but here's the technique needed to push start a big single.

Check everythings in the on or run position, yes I've done it doh

Always pull it back on compression first, this is the most important bit, it gives you nearly 2 revolutions before hitting compression again and is the main reason most people fail at push starting singles.

Select quite a high gear, this gives you a gearing advantage from the back wheel to the engine, I usually select 2nd or 3rd

Don't run for ages before dumping the clutch, once your moving at a reasonable speed it'll work.
Also you'll get better grip if you drop your arse onto the seat at the same time.

On a carb bike that normally starts straight away on the starter you should get the same immediate start so be ready to grab the clutch again.
Most EFI bikes seem to have to turn over once before firing so I guess you'll have to push it for a few yards before it'll fire.

I can push start my KTM 640 no problem and I used to race grasstrack on 500cc Jawa's and Weslake's that run 13:1 compression ratios and they had to be push started in muddy fields.

Remember that the most important bit is to pull the motor back on compression.

Steve

Actually Steve you are not late. Good information is always timely to share with others. :welcome:

Thank you for the tip on making sure you bring the bike to proper position prior to taking off to make it easier.

Cheers

Much, much safer to tow footpeg to footpeg rather than from the headstock, but as you say, on the towed bike just wrap the rope around the peg and put your foot on it.

For someone who is new to this stuff can you explain further what you mean by this? Thanks

I think this is what he means......

On a four stroke engine you have "four strokes" One of those is the compression stroke which is when all the valves are closed and the piston is compressing the fuel/air.

This is hardest point in the cycle to turn an engine over.

So, I think he means to get past this stroke so you can get a little momentum in the engine before it hits the compression (ignition) stroke of the engine again.



Or I could be completely wrong... :innocent:

Ted is sort of right but the way it achieve this is to put the bike in 2nd or 3rd and pull it backwards until you can't pull it anymore. The piston has backed up against the compression (rather than gone forward just past it - only possible to do that with an old style decompression lever, AFAIK).

You see me doing it in this video:
Desert Riders ~ Push starting a Honda XR650L in the Sahara - YouTube
@ 1.34 to 41

You then pull in the clutch, switch on and take your run up. When after a few paces you dump the clutch while also jumping on the seat, the motor will have spun up a bit of momentum before it hits compression again (jumping on the seat ensures added traction so the motor turns and hopefully starts, rather than the wheel locks).

Doing the same without pulling back on compression will probably see the wheel lock rather than engine turn, especially on a big single. On a little 125 it's probably not important.

Ch

Thanks guys, thought it might be something like that. And thanks Chris for the practical demo. To go all the way to the Sahara just to shoot a demo vid...I'm touched :)

:oops2:.....you have to love that youtube vid!

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.If you listen carefully.....
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Way out in the distance....
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You can hear the electric starter cranking the engine.....:Beach:

Yes, thats why CS says to the other guy, "I owe you a tank of petrol".

Boyer bransden power box
 

This device may be of use to some; it can be retrofitted to most bikes and advice sought from the makers.

http://www.horizonsunlimited.com/hub...3q6lFYq9dRAf/Z

Basically, it is a regulator/rectifier with an integrated capacitor. The reg/rec is a common point of failure in the charging system as the lack of charge to start the engine when the main/chassis battery is flat. I havn't tested it and advice should be sought from the makers but the capacitor may hold sufficient current to operate the FI system when the main battery can't. It also has circuitry which switches of the lights until the engine (and charging system) begins to operate.

Boyer Bransden Electronics Ltd

Boyer Bransden Electronics Ltd

Snetterton, about 1973. 1000cc class. (Can't use kick start).
McCrank is No. 26, Norton Commando.

Pull back against compression, even with a twin.
http://i1263.photobucket.com/albums/...a/P1000187.jpg
Looks like all eyes are on the starter, so flag not dropped yet. (My dad took these photos, have no memory of the particular meeting).


The accepted benchmark used to be - 3 good strides, then bum on seat and drop clutch in one action - left foot on left footrest.
Or 4 strides if 3 REALLY wasn't enough.

http://i1263.photobucket.com/albums/...a/P1000189.jpg
Bum is on seat, but a slow start - No. 52 in front already has leg over....

I thought there might be videos to find of push starts for Manx Nortons and the like. But all I could find was this, which shows it OK I think.
Suzuki Racing in the early 60s - Part 1 - YouTube
Small 2-strokes need a lot of running to get going.

On to the TT, 1960s:
Suzuki Racing in the early 60s - Part 1 - YouTube
Competitors and spectators start the fortnight like this.
Some on-bike footage as well - my, how that circuit has changed!

A good tutorial here:
Suzuki Racing in the early 60s - Part 2 - YouTube

Another lesson here:
Suzuki Racing in the early 60s - Part 2 - YouTube
All small 2-strokes

Back to the original question - I've found over the years that my Aprilia Mille requires a good battery just to boot the computer. If I connect up a battery that isn't fully charged, the computer still boots (lights flash and needles jump). And the starter motor turns on the button, but no engine start. The computer hasn't booted properly.
Connect a fully charged battery, and all is OK.

So my experience of an EFI bike, you definitely need a good battery to start without use of the starter motor.
A lot of competition riders these days remove their starter motors (heavy) and use rollers to start, but always with a good battery I think.

EFI still needs 12V, no matter how low the amps.
 

Another factor to consider is whether your battery is just flat, or whether one of the (6) cells has died. If it is the latter then you may find that your bike isn't going anywhere no matter how much you push/pull/bump/jump start it.

I had this problem 5 years ago in Siberia on my EFI Burgman 650. The bike would not continue running once it had been jumpstarted. I still haven't fully determined the reason for this but I believe it was either the fact that the fuel pump required a minimum of 12V to operate or that there was some clever programming in the ECU that told the injectors they could only operate with that voltage.

Indicators, headlight, horn etc, would operate but the bike would not start until it saw at least 12V (battery showed around 10.8). I was fortunate enough to be able to borrow a 12V lower amperage battery which got me from Chita, to Irkutsk, where I was able to purchase a replacement.

Kind of an old post, but do you recall which gear you put the bike in?

A couple of years ago I managed to bump start my V-Strom in first gear after several unsuccessful tries in second or third.

A few months ago I tried again to bump start the bike, in both second and first. I wasn't able to do it and had to pull out my jumper cables.

Jamie

My bike is not EFI, just carbs - Honda Tornado XR250... it has an electronic start only...

... if the battery is completely dead, could this bike be started with a hillstart or run and jump? I never understood the mechanics of hill starting - can anyone enlighten me?

Cheers!
Rtw

A Tornado would be easy to jump or hill start. Nice and light and old school - the golden era of jump starting, as shown above.

If the job of the kickstart or electric start is to spin the engine into life, then jump/hill starting is achieving the same thing by using the energy of the moving bike - wheel turning the chain turning the gearbox and so the piston - to fire it up. That is assuming the motor is generating enough charge to make a spark. With no efi to run, I am sure XR is

A good way to practise would be with a warm engine rolling down a quiet hill somewhere.
Whatever gear you're in, pull the clutch in and hold it in, then kill the engine with the kill button on the right bar - revs drop to zero but ignition is still on.
Bike is freewheeling. Now gradually let out the clutch, the whirring gearbox will engage with the clutch which will spin up the piston. Bike speed will hesitate a bit, then fire up and run as before. Now, see yourself doing that from a standing start with a cold engine. That is a hill start.

Lesson 2 is learning to do the same with a run and a jump on the flat. Not always so easy, especially with tall, big singles that are cold, as shown earlier, but a good skill to learn.

Ch

Yup.....

All you are doing with a push start is turning the engine over , like a starter motor would..

No battery = No starter motor.

The starter motor turns the engine over which turns the generator which produces the juice for a spark plug..

Pushing a bike whilst in gear will turn the engine...

Just like a running engine, in gear, will turn the back wheel.

Simple enough ?? :cool:

Following Chris Scott's instructions you might need to add this bit.

Once free wheeling you will have to reset the kill switch on most bikes for it to work.......:smartass:

Allow me to describe an alternative:


Find yourself a decently large shaft drive touring bike with a car type clutch and a marginally unfit 40-year old willing to try bump starting on a hot day. Push the bike to the top of a nice little hill and have a quick fag while waiting for the pain in your chest and pins and needles in your left arm to go off.


Put the bike in third gear and holding the clutch in gently push off down the hill. Wait until you are up to third gear sort of speed and let the clutch out. There will now be an odd whirring noise as the tractor like gearbox slips gently into the false neutral between second and fifth. Pull the clutch in and stomp heavily on the gear lever until you get the expensive crunching noise that means you have selected one or more gears. Drop the clutch again. As the back wheel locks solid and the whole bike lurches towards the middle of the road pull the clutch in again and steer towards the kerb. Coast to a halt in the middle of the busy junction at the bottom of the hill.


Nimbly hop off the bike, disengage your boot from the top box and heave the monster from it's back destroying 45 degree angle to roughly upright and push to a nicer location. Have another fag and wait for the symptoms to go off again.


Now either repeat with the ignition on or fit a better battery!


Andy

The moral to Andy's story.. Keep your Tornado.. ( and look after your battery) :)

Having never personally having to push start a bump start an EFI I wonder if this is due to the ignition circuit activating the priming function of the fuel pump.

That sounds remarkably like my experience of being 27 years old and trying to start antique Enfields at 5,200m :)


Ted,

Yep got that I think! So even if I removed the battery and threw it away, I could still start my bike? If you can bump start a bike like that without a battery, then how to killswitches/ignitions work? Do they break a circuit which then prevents charge reaching the sparkplug/s?

Depends on the bike but these days, 99% of bikes need the battery there as part of the circuit.

Your ignition IS a switch. And yes, they break the circuit. They prevent or allow the flow of electricity in a circuit.

Most of TWB's technique is par for the course with bump starting anything much over 250cc - in my experience anyway. The best way round it is to pay the bunch of school kids that often gather whenever you stop to push. All you do is imperiously sit on the bike and yell at them to push faster while deciding when to let the clutch out. Worked for me a few times :thumbup1: :rofl:

In case your battery goes flat
 

Keeping it simple and avoiding all that 'push-puff-'n stuff' :Beach:
Fit a positive terminal accessible point
Use a small power bank weighing in at....300 grms!
Connect terminals-turn ignition key- and fire up engine - easy peasy
Why struggle! making technology work for you- it fired up my F650 13 times and used only 25% of its stored charge.
Once you're on your way again, plug in 12 volt charger to re-charge power bank- Sorted-
( btw-it can also charge up phones, tablets, water filters, computers, rechargeable torch batteries etc. via its USB outlet and it even has a torch built in. Free virtual fruit basket to whomsoever knows this product!)

That sounds remarkably like .... a battery. :confused1:

However I'm guessing it wouldn't be that easy so how about one of these -

This Portable USB Charger Battery Pack Can Also Jump Start Your Car


Available on Amazon for the price of .... a battery.

It's an auxiliary battery yeah. Pretty expensive if I remember correctly..

As this is the bodge fix section should we mention plugging in a battery charger then pushing the button?


This is a ticking time bomb of potentially melted wiring but if you have the charger and access to the mains.....


I've seen the results of trying to start a bus from a welding set too, don't try that unless you want to get on the telly.


Andy

backofbeyond
 

gets the fruit basket- :smiliex: It is similar if not congruent. 200CCA Constant - 400CCA Max

Various versions available price range £30-£100, I assume they use some form of capacitor to provide enough Power to turn an engine over. Useful gadget especially as it can be used to recharge all the usual gadgets.