Fuel Cap Breather

[Jamieg285]

For your starting problem, have you ruled out the fuel pump?   Are you waiting for long enough after turning the ignition on, for the pump to fill the carbs before hitting the starter?

[darrsi]

For your starting problem, have you ruled out the fuel pump?   Are you waiting for long enough after turning the ignition on, for the pump to fill the carbs before hitting the starter?

Normally takes a weekend off the bike for that to start rattling away,  otherwise there's already fuel in the carbs after just 9 hours.

[darrsi]

I was gonna wait until the end of the week and report that since my shiny new fuel cap has been fitted the bike has started on the button morning and evening without any issues, and been running absolutely fine.


Well it was until this evening.


I'll make it simple, the bike was put on the centre stand for a change behind a wall at work due to the high wind and ropey weather.


On centre stand, all lights and accessories off, i start the bike with the choke.


I adjust the choke until it's maybe a third of the way and happily revving away but not anything mad, then leave it alone to put my balaclava and lid on.


After 30 seconds of happily purring away, the engine just stops dead, as if i hit the kill switch. It didn't die out slowly as if starved of fuel, just off.


Then, it won't start, after about 3 attempts.


I switch off, finish doing my lid up and putting gloves off, take it off the centre stand and then it starts straight away as if nothing is wrong and i'm off home with no problems at all.


Question is, what can stop an engine dead after 30 seconds of revving on the choke at around 2500rpm?

[fazersharp]

I just don't think your bike likes you.

[Fazerider]

... Question is, what can stop an engine dead after 30 seconds of revving on the choke at around 2500rpm?

Sudden temporary loss of sparks would be my guess.
It also allows a build-up of unburnt vapour in the exhaust system which is ideal for elephant gun effects when the sparks resume normal service.

[darrsi]

... Question is, what can stop an engine dead after 30 seconds of revving on the choke at around 2500rpm?

Sudden temporary loss of sparks would be my guess.
It also allows a build-up of unburnt vapour in the exhaust system which is ideal for elephant gun effects when the sparks resume normal service.

It's not air, and it's not petrol, so it is pointing towards electrical now.
So what am i looking at now to cause these intermittent loss off sparks?

[Fazerider]

There are many, many possible causes.
It could be a failing component somewhere or it could be an intermittent open circuit or (less likely) intermittent short circuit in the wiring. You might be able to narrow down the search if there are any other unexplained faults, such as flickering lights or intermittent glitches on the instrument panel for example.
Sadly vehicle wiring problems are a pain in the arse… and they're a hundred times worse if they only show up when they feel like it (i.e. when you're late for work or at midnight on your way home).

[Dudeofrude]

Would it not be worth getting an auto electrician to take a look? Might cost you an hours labour but he would either find the problem or at the least check off a load of things that its not?

[darrsi]

I just don't think your bike likes you.

I buy it shiny new things, i take it out, i even buy it booze, where am i going wrong? 

[slappy]

I just don't think your bike likes you.

I buy it shiny new things, i take it out, i even buy it booze, where am i going wrong? 

You have to tell it you love it, cuddle it and never ever even glance at a newer shinier bike, especially if it has a bigger engine.

[locksmith]

I just don't think your bike likes you.



I buy it shiny new things, i take it out, i even buy it booze, where am i going wrong? 



You have to tell it you love it, cuddle it and never ever even glance at a newer shinier bike, especially if it has a bigger engine.

Looks like the lyrics from a Seasick Steve song         

[fazersharp]

Its not you - its her, she wants more out of life, a little excitement once in a while, yes you take her out but its always to the same place, she feels stifled and and feels that she has so much more to offer than what you can give her she longs for the open road and sweeping bends and although deep down she still loves you she is bored with the daily commute. Which is why she is always reluctant to start.   

[darrsi]

Its not you - its her, she wants more out of life, a little excitement once in a while, yes you take her out but its always to the same place, she feels stifled and and feels that she has so much more to offer than what you can give her she longs for the open road and sweeping bends and although deep down she still loves you she is bored with the daily commute. Which is why she is always reluctant to start.   

You've met my ex then 

[darrsi]

There are many, many possible causes.
It could be a failing component somewhere or it could be an intermittent open circuit or (less likely) intermittent short circuit in the wiring. You might be able to narrow down the search if there are any other unexplained faults, such as flickering lights or intermittent glitches on the instrument panel for example.
Sadly vehicle wiring problems are a pain in the arse… and they're a hundred times worse if they only show up when they feel like it (i.e. when you're late for work or at midnight on your way home).

Started fine again this morning, i'll see if it behaves tonight in a minute.

[esetest]

Worn ignition maybe .

[darrsi]

Aaaaaaaaaaarrrrrggghhhhh 




Okay, now i have that out the way.


Bike on side stand, sitting slightly uphill outside my work.


Start the bike....cuts out after one second. Repeat this about 5 times.


Put all my gear on, sit on upright bike, start with choke, and it runs for about 20 seconds then just totally cuts out?


Decide to shake the bike from side to side (rather than jump up and down on it) then it starts straight away, and i'm off home again with no problems whatsoever!


What the foc is going on? 


The fact it's been sitting outside all day, and then it starts after sloshing the fuel about now brings me back to thinking about moisture/condensation sitting in the carbs again.
It could explain why it ran okay all the way home, whereas if it was electrical would it not play up again at some stage during my journey?

[Simon.Pieman]

Check the wiring and connectors of the sidestand cutout and make sure the switch isn't covered in cack. If it's the plunger type switch on your bike make sure the plunger is moving freely and not getting stuck, contact cleaner can be used to free these up.

[darrsi]

Worn ignition maybe .

The bike does eventually start though, and so far in the last few days has run between 20 and 30 seconds before the engine just stops dead.
Horrible thing is, this is gonna turn out to be something really stupid, and probably easy to fix......as soon as i know what the foc is wrong with it?

[darrsi]

Check the wiring and connectors of the sidestand cutout and make sure the switch isn't covered in cack. If it's the plunger type switch on your bike make sure the plunger is moving freely and not getting stuck, contact cleaner can be used to free these up.

Sidestand switch has been bypassed, that was when all this trouble started last summer and it was the prime suspect at the time.

[red98]

Mmmmmmm.....ESETEST ...could be onto something there...is the key loose/sloppy in the ignition ?


Agree  with you that it will probably be something simple....might be worth by-passing the ignition just to rule this one out....wont cost you anything trying   

[darrsi]

Mmmmmmm.....ESETEST ...could be onto something there...is the key loose/sloppy in the ignition ?


Agree  with you that it will probably be something simple....might be worth by-passing the ignition just to rule this one out....wont cost you anything trying   

Key feels okay to me.
How would i bypass it?

[Fazerider]

Mmmmmmm.....ESETEST ...could be onto something there...is the key loose/sloppy in the ignition ?




Agree  with you that it will probably be something simple....might be worth by-passing the ignition just to rule this one out....wont cost you anything trying   

Key feels okay to me.
How would i bypass it?

With the main fuse out, get to the connector bundle under the tank, disconnect the two plugs from the ignition and make up three links to mimic what the switch does in the "on" position (it's fairly clear which ones to link using the diagram in the manual).
Plug the main fuse back in and your bike is on and ready to start.


As you say though, it's odd that the bike doesn't show up any glitches once it's running properly… if it was a dodgy connection it would be vibration sensitive and you'd expect it it cut out occasionally when hitting bumps.
On the other hand, it doesn't sound much like water contamination either, particularly as you should have dissolved any present with your isopropanol dosing regime.


I wonder if it's flooding? Shaking the bike from side to side might have unjammed a stuck float perhaps?

[darrsi]

Mmmmmmm.....ESETEST ...could be onto something there...is the key loose/sloppy in the ignition ?




Agree  with you that it will probably be something simple....might be worth by-passing the ignition just to rule this one out....wont cost you anything trying   

Key feels okay to me.
How would i bypass it?

With the main fuse out, get to the connector bundle under the tank, disconnect the two plugs from the ignition and make up three links to mimic what the switch does in the "on" position (it's fairly clear which ones to link using the diagram in the manual).
Plug the main fuse back in and your bike is on and ready to start.


As you say though, it's odd that the bike doesn't show up any glitches once it's running properly… if it was a dodgy connection it would be vibration sensitive and you'd expect it it cut out occasionally when hitting bumps.
On the other hand, it doesn't sound much like water contamination either, particularly as you should have dissolved any present with your isopropanol dosing regime.


I wonder if it's flooding? Shaking the bike from side to side might have unjammed a stuck float perhaps?

The thing i find weird is that i have a reasonably trouble free start in the mornings, when the bike is garaged at night, but once left outside work for 9hrs that's when i have the main issues.


I'm trying to give as much detail as possible in case it means anything.
Like on Thursday the bike was on the centre stand, then started once pushed off it, then yesterday it was on the sidestand but only stayed running after "shaking" the bike from side to side.
I know it'll start eventually with perseverance, but for one it's embarrassing, and secondly, it just ain't right.

[darrsi]

A couple of my mates just popped round my house and i tried starting the bike in front of them and it played up from the off for about 5 minutes until i shook the bike a few times then it started and eventually ran okay.
So on that evidence and procedure we all agreed that i either need to drain the carbs and tank, in case i've picked up some dodgy fuel from somewhere that may have water in it, or just take the bike for a good blast and see if i can burn it off whilst having a little bit of fun at the same time.
I have another week off work to play with although i keep hearing reports of upcoming dreadful weather so i'll have to pick my moment, but i have to get this sorted 'cos it's driving me bonkers.

[slappy]

With you shaking the bike and then it starting ok I wonder if there is crap in the tank that is settling round the outlet for the  petrol tap under the tank. When the bike is stood the crap sinks to the lowest point and restricts the fuel flow.
Or possibly I am talking crap, it has been known