CBR400 won't start...

[harriebird]

never thought this would happen but......

FINALLY got him back after his service and patch up after my little accident the other week. sean the mechanic rings me and asks if i ever get problems getting him started.

so i said he doesn't normally start straight off the button but a little choke and he's fine. i'd thought a set of new plugs and valve clearances at his 16000 mile service (the one he's just had) would sort it out so wasn't too worried.

but it's even worse now, i left him outside on thursday night and he woulnd't start at all on friday morning. the starter motor is turning but the engine isn't at all. you can hear one of the cylinders starting to try but nothing else.

so i took the cb to work on friday morning (748 was still missing a brake lever)

tried to start the cbr on saturday afternoon, he was fine. but there's a slight intermittent ticking noise, can't work out where it's coming from but it sounds like the left hand side of the bike under the fuel tank. ran him for a few minutes, lovely i thought.

today he won't start again.

is it a battery thing do you think? he is a 16 year old bike and has just been stood in a garage for 4 weeks, normally before that he got a run every day. maybe he just needs new juice? i'm going to ring sean and see if he can think of anything else.

i'm a bit upset, can anyone suggest anything? i'm meant to be doing rockingham on him but that's not gonna be a goer if i can't get him started now is it.... :(

the 748 is rapidly approaching his next service and it's hard work filtering on him, especially down the hill to the mini roundabout by the station in billericay

[Lateshift]

It may be that the battery has died beyond a level where there is only just enough power in it to start it when its warms (makes a big difference in cranking power). I assume the bike has got an electronic fuel pump supply to the carbs, in which case it could be that the ticking is the fuel pump doing its best to work with limited battery power.

What tends to happen with cases like this is that the bike once it starts, tries to divert as much electricity to the battery to get it charged again, however it still has to supply the fuel pump and any other electrical items too, this means that the battery never fully gets charged (once in such a state) because its trying to do two things at once (badly).

Have you got a multimeter? if so stick the multimeter across the battery terminals to see what the battery is working at, rev it to around 3000 and note the voltage before and after turning the lights on.

Definitely sounds like low cranking power to me though, although its like anything, unless you see it, its hard to put a definite on it :)

You could try taking the battery off one of the other bikes to see if that starts it straight away, should give you a good indication then ;)

[harriebird]

sorry to be thick but is one bike battery much the same as another then?

[kasandrich]

If your engine is turning over, then I doubt its the battery, the fact that you left it out overnight and it wouldn't start in the morning, but it was OK saturday afternoon (nice warm day) it sounds like damp to me, you could try spraying WD40 around the spark plugs and leads.

[Lateshift]

the only thing that tends to be different is the cranking power (in amps)

it used to be a common problem that the 12v 10ah battery after while was never powerful enough to turn the engine so people changed to a 12v 12ah battery instead.

a bigger engine generally tends to require a little more cranking power due to the compression in the cylinders.

However Juliets bike runs on a ZX9R/GSXR600/GSXR750 battery, and my GSXR750 has her old ZXR400 battery on it at the moment :D

Other than the cranking power the only other real difference is the actual size of the battery :)

The battery doesnt have to fit on the bike, you just need to connect it to test it, at least then you will have an idea if the battery needs replacing for definite :)

The battery on the NC29 is a YTX7A-BS 12v 6ah type (uses 6 amp cranking power)
The battery on the CB500 is a CTX9-BS 12v 8ah type (uses 8 amp cranking power)

It wouldnt hurt to use the 8ah battery to turn the NC29 over ;)


Pretty much what you have here is a battery that sounds low enough to not be able to generate a spark whilst trying to crank the starter over at the same time, once the battery/bike gets a bit warmer (battery performance is degraded when cold) it has just enough to do both ;)

[Lateshift]

If your engine is turning over, then I doubt its the battery, the fact that you left it out overnight and it wouldn't start in the morning, but it was OK saturday afternoon (nice warm day) it sounds like damp to me, you could try spraying WD40 around the spark plugs and leads.

Not the case at all Kas, bikes work differently like that ;)

Its a simple case of a small batteries struggle to do 2 things at once,

If you think of the ignition circuit as both trying to supply cranking power (amps) to the starter whilst simultaneously trying to supply voltage to the coils (enough to be able to energise them and build up enough to produce a spark) then as soon as the battery gets to around 11.8 volts it cant handle it.

My Mille in the cold would be a prime example of it, if it had any less than 12.1 volts in the battery from cold, then as soon as i turned the key it would drop to 11.8 and would just sit there spinning the engine, and consequently flooding.

As soon as i tried it with the heavier battery, it would fire straight away.

Probably the least complicated bit of kit on the bike and yet the one that causes the most trouble.

Another good example was on my GSXR on the Friday before Lydden.

The battery had sat on there for a month since i stripped the bike, i went to start it and just got a fuel pump prime and that was it.

Jump started it with the pack, and within ten minutes the wires to the regulator/rectifier were starting to cook, simply because the battery was that low it was trying to draw a massive amount of voltage to recharge itself, and at the same time running like a bag of crap because it couldnt do 2 things at once.

Stuck on Jet's old ZXR400 battery and it fired first time and everything weas peaceful on Waltons mountain ;) :D

A difference in a few degrees (especially when the night before was really crisp) can be enough to degrade a battery so much that you could end up binning it, thinking that its knackered, when 12 hours later its perfectly fine ;) )

[Lateshift]

Just a quick check, it would seem that the CB500 battery you have is only 13mm taller than the NC29 one, the other dimensions are the same, if you have been using the CB500 for work then chances are its in good nick anyway (well conditioned) a simple swap of the battery just to test that the CBR starts should be enough to confirm it :)

The extra 2ah cranking power wont hurt it, that is just the power it is able to put out if asked of it ;)

[kasandrich]

Not the case at all Kas, bikes work differently like that ;)

Its a simple case of a small batteries struggle to do 2 things at once,

If you think of the ignition circuit as both trying to supply cranking power (amps) to the starter whilst simultaneously trying to supply voltage to the coils (enough to be able to energise them and build up enough to produce a spark) then as soon as the battery gets to around 11.8 volts it cant handle it.

My Mille in the cold would be a prime example of it, if it had any less than 12.1 volts in the battery from cold, then as soon as i turned the key it would drop to 11.8 and would just sit there spinning the engine, and consequently flooding.

As soon as i tried it with the heavier battery, it would fire straight away.

Probably the least complicated bit of kit on the bike and yet the one that causes the most trouble.

Another good example was on my GSXR on the Friday before Lydden.

The battery had sat on there for a month since i stripped the bike, i went to start it and just got a fuel pump prime and that was it.

Jump started it with the pack, and within ten minutes the wires to the regulator/rectifier were starting to cook, simply because the battery was that low it was trying to draw a massive amount of voltage to recharge itself, and at the same time running like a bag of crap because it couldnt do 2 things at once.

Stuck on Jet's old ZXR400 battery and it fired first time and everything weas peaceful on Waltons mountain ;) :D

A difference in a few degrees (especially when the night before was really crisp) can be enough to degrade a battery so much that you could end up binning it, thinking that its knackered, when 12 hours later its perfectly fine ;) )

Sorry Mick, wasn't meant to contradict your posting, it was just another suggestion of something that was easy to try. Its difficult to know whats happening without seeing and hearing it. Harrie said the starter was turning ok but the engine wasn't, which doesn't make sense, so I took it as the engine was turning over Ok but not starting, and as it had come from a workshop where they had trouble starting it, I assumed they would have charged the battery and if faulty diagnosed that before returning it. Thus I was looking away from the battery at other possibilities.

[Lateshift]

Its okay, i know you werent disagreeing (just putting another twist on it ) :)

As far as Garages go, its my experience now that they will do only the work that is required in most cases now, if the bike was bent, the chances are they would have done the work on straightening it only, i bet they didnt even fire the engine up ;)

The only reason this springs to mind is because of what happened on my ZX9R.

A bitch to start when it got cold, ran crap at low revs, electrics played up, changed the battery and all sorted.

The Mille was the same over Winter once or twice too, exactly the same symptoms when it had been sat there for 2 months without any starting :)


On a different note, if the starter was turning freely and the engine wasnt "turning" (big difference between firing and turning) then it would only be down to 3 things, the starter clutch having gone (normally squeals its head off), the idler or starter gears being knackered, or even worse a seized engine.

However she mentions that the bike started later on in the afternoon, so i think the battery warming up has more to do with this one :)



The electric current generated by a battery is produced when a connection is made between its positive and negative terminals. When the terminals are connected, a chemical reaction is initiated that generates electrons to supply the current of the battery. Lowering the temperature causes chemical reactions to proceed more slowly, so if a battery is used at a low temperature then less current is produced than at a higher temperature. As the batteries run down they quickly reach the point where they cannot deliver enough current to keep up with the demand. If the battery is warmed up again it will operate normally.

[kasandrich]

......Simple then innit? Blow lamp on the battery http://www.essexbikers.co.uk/forum/images/icons/icon12.gif


NO I AM NOT SERIOUS! PLEASE DO NOT TRY THIS AT HOME!!!!!!!

[Perilous]

Yep have to go with that.

CBR 400s and VFR 400s are realy fussy about batteries starting from cold. If you ever to a spark test you'll see they have a tiny little spark. If the battery's tired at all and they don't catch almost immediately they flood up and then it's all over.

If nothing else it's something thats easy to eliminate before you start deving deeper.

[harriebird]

As far as Garages go, its my experience now that they will do only the work that is required in most cases now, if the bike was bent, the chances are they would have done the work on straightening it only, i bet they didnt even fire the engine up ;)

they actually did a full service on it so i'm not sure why they didnt think the battery might have soemthing to do with the starting problem...but never mind, i know it's got new plugs and when it runs it's definitely not rattling any more so the valve clearances have been done.

i'm happy with what sean does tbh, but am a bit surprised when he mentioned the crap starting that he didnt suggest anything to do with the battery.

thanks people, we shall start with the battery tonight (after i get my sodding foot x-rayed so could be a late one :rolleyes: )

[Lateshift]

The problem with all that Harrie, is that if its working at the time when they service it, then there is nothing for them to look for ;)

And on a service the bike would probably be running for all of 10 minutes at most, and even that would be only to run fresh oil round the engine ;)

Sean may well be the best mechanic in the world, but you cant fix something if its not causing a problem at the time, the amount of people that have battery problems is no coincidence, its an expendable item unfortunately, and could work fine one day, but be a pain the next, especially on a bike that hasnt been run for a couple of weeks.

Lastly bear in mind that a bike standing at idle (in the case of a service) is not charging properly and is still pretty much discharging, this is why when you sling a multimeter across to check the battery state, you need to ideally throttle up to over 3000 rpm, you should see the voltage rise then as the alternator starts to do its thing :)

In normal circumstances a good half hour run on open roads, using minimal electrics (minimum turn signals and headlamps etc) is enough to recharge a struggling battery :)

[Lateshift]

......Simple then innit? Blow lamp on the battery http://www.essexbikers.co.uk/forum/images/icons/icon12.gif


NO I AM NOT SERIOUS! PLEASE DO NOT TRY THIS AT HOME!!!!!!!


Its funny you say that, but out in the Arctic (or at least sub zero conditions) we have to use a crude kerosene heater on our generator batteries to keep them at a temperature where they will allow the battery to provide enough power to keep a spark at the plug ;)

One trick that can be used for bad cold starters is to sling a blanket over the bike, and throw a lamp with a 60 watt bulb underneath the bike and leave it overnight, 60watt provides enough heat to keep condensation out and keep the oil thin on an engine believe it or not ;)

Top tip of the day from someone who spent 3 months at 6500ft and -40 degrees :D :D

[harriebird]

In normal circumstances a good half hour run on open roads, using minimal electrics (minimum turn signals and headlamps etc) is enough to recharge a struggling battery :)

it had this on wednesday night, came to the pub and back, and was fine to billericay and back again on thursday, but then stood outside thursday night and must have just lost the will to live again :rolleyes:

i just meant that i found it odd that sean had had a discussion with me on the phone about how the bike wouldn't start very well unless it was warm, without mentioning or thinking that maybe the battery might be to blame.

he's the only guy i've found round these parts who i'll let anywhere near my bike now!

[Lateshift]

I appreciate what you are saying, its no different than me not taking my Aprilia to anyone other than Southern Cross.

I dont think there is anything untoward in the fact that they recognised the fact that it took a while to start from cold, but at the same time i think he can be let off for not checking why, sometimes they probably just look at a bike and think "well its knocking on a bit but hey it started eventually" :)

I feel pretty confident that he would have been able to sit down with a cup of tea and pretty much have an immediate idea what would be causing it, whether he had the time to sort it out or whether or not he actually thought it was a long term problem that wouldnt just sort itself out is a different matter.

As i said before, the ZX9R played up pretty much the same way, i was up at Burnham when it went dead on me, a quick trip from there to Maldon sorted it out, but 2 weeks later it just went dead again,

these things happen i suppose :)

[kasandrich]

I feel pretty confident that he would have been able to sit down with a cup of tea and pretty much have an immediate idea


You don't know Sean Davies, he doesn't do sitting down with a cup of tea, he is on the go all the time. Isn't he Harrie?

[Lateshift]

Perhaps then thats where the problem lies, no tea! :D

You dont need to be a mechanic to know that coffee and tea breaks get the job done quicker, it goes with the smudged line of grease across the face! :D

[MICKTLS]

it does help sometimes to walk away have a cuppa otherwise you can get very short sighted on a prob or fixated so much that you dont see the obvious ......well thats what we do lol
:laughboun

[harriebird]

You don't know Sean Davies, he doesn't do sitting down with a cup of tea, he is on the go all the time. Isn't he Harrie?

yes he is.....sigh.....:love1 ....just allow me a moment there, he's lovely!!!!

he does however leave on time when it's his dad's birthday :grin2

multimeter has been had out, phil reckons the alternator is working super hard so we're going to try a new battery. i'd forgotten i always leave the lights on to start it as well and this obviously wasn't helping as when i switched them off it started a lot easier, and then once it was running again i switched them on everything dropped again!!

[WebTone]

I'm off wednesday after a quick MRI at the hospital. If you need help shout and I'll bring round my magic Blu-Tack. You never did get to see what that was for.LOL.

[harriebird]

hello stranger!!!! :grin1

new battery is in, no problems at all. started on the button :grin2 so obviosuly had to take him for a rather nice run to get used to him again for rockingham :skip

[Lateshift]

all good then, a week to go ;) :D

[harriebird]

yep, can't bloody wait!!!!

[harriebird]

arghhhhhh....the saga goes on.

(i'm going to post on 400greybike too)

So. The battery is fine, got a nice new one. I've checked a variety of fuses, sensors and switches - amazing once phil's hand is bust that he will let me do the work while he passes the spanners rather than the other way round :grin2

tried a new CDi, new HT leads, new coils but still nothing.

The fuel tank is off, and when I switch the ignition on and try and start him, nothing happens in the fuel pump apart from a very occasional thump.

It says in Haynes i should be able to feel the fuel pump running with the ignition on - is it just needing the fuel tank connected to be able to run properly, or should it at least be doing something?!

I'm sorry this is such a dumb arse question but i have just found out i am going to be able to keep the bike after all, so i want to get him running and all nice again so i can stop commuting on the GSXR....

thanks for any help xxx

[Mi5ter E]

Sounds to me like you should get rid of it a buy a nice fzr400r ex-up

[harriebird]

NO :p heehehhee

we've been through too much together now, i really don't want to get rid of it :(

[bayonet]

arghhhhhh....the saga goes on.

(i'm going to post on 400greybike too)

So. The battery is fine, got a nice new one. I've checked a variety of fuses, sensors and switches - amazing once phil's hand is bust that he will let me do the work while he passes the spanners rather than the other way round :grin2

tried a new CDi, new HT leads, new coils but still nothing.

The fuel tank is off, and when I switch the ignition on and try and start him, nothing happens in the fuel pump apart from a very occasional thump.

It says in Haynes i should be able to feel the fuel pump running with the ignition on - is it just needing the fuel tank connected to be able to run properly, or should it at least be doing something?!

I'm sorry this is such a dumb arse question but i have just found out i am going to be able to keep the bike after all, so i want to get him running and all nice again so i can stop commuting on the GSXR....

thanks for any help xxxIf a fuel pump has no fuel going through it (i.e. the tank is off) then it usually makes a racket and clicks like mad. Try plumbing the fuel tank straight into the carb (connect the tap to the out pipe of the fuel pump) and see if it starts after a couple of goes. You need to keep the fuel in the tank higher than the bottom of the carbs. If it's anything like a CBR600/Africa Twin fuel pump (Mitsubishi made) they do die relatively early.

[harriebird]

according to 400greybike (just searching through a load of related posts!) it is a mitsubishi pump so this could well be the problem :grin2

[bayonet]

according to 400greybike (just searching through a load of related posts!) it is a mitsubishi pump so this could well be the problem :grin2I had 3 Mitsubishi electric pumps and one Mikuni vacuum pump on my last Africa Twin. The electric pumps have contacts inside which eventually weld themselves shut. A new pump from Honda is about £150. From Dave Silver the same pump is about £80. http://www.xrv.org.uk/phpBB2/ sell an american replacement pump for about £40 which so far hasn't caused anyone any worries. Plumb the tank directly and see if the bike fires up and then you know that's the problem before stumping up any cash.

[harriebird]

lovely, i will give it a whirl. thank you :cuddle

[harriebird]

bloody thing :love1 won't even spark now. I'm really starting to run out of ideas :(

[Mi5ter E]

went for a ride on the fzr today rides superb shame ive gotta sell it

[harriebird]

yeah isnt it :grin2