Fuel Cap Breather

[darrsi]

Next time it happens take a plug out and check if it's sparking and what condition it's in if it's wet etc

Can't see why it wouldn't be, as said once started it runs fine.
I chopped the ends of the HT leads and rescrewed the caps on firmly, got new Iridium plugs, and i've covered them in WD40 as well to avoid damp issues.
Don't forget, this isn't a recent issue, it's been happening since summer so i've done all the main checks and replaced a few parts along the way.
The air vent theory was only thought of when i was searching the web a few days ago, but i've got this week off work so not been doing the commute.
I was out on the bike yesterday but i'd already opened the fuel cap to blow air down the hole, plus the weather was warmer, and the bike started up fine straight away.
The main time it plays up is after it's been sitting outside work all day as i'm going home. It's played up a few times in the morning but not as bad, although it is garaged at night so that may be why.

[slappy]

Don't know if you have tried this but next time you start it up at work open the fuel cap first, then start it up. If it starts up ok then I would  check  that  all the hoses are clear of debris and gunk and not kinked and replace them. I realise that you have said before that you have  checked them but if it is mayonaise type gunk it is hard to clean it out properly and replacement hose is cheap.

[darrsi]

Don't know if you have tried this but next time you start it up at work open the fuel cap first, then start it up. If it starts up ok then I would  check  that  all the hoses are clear of debris and gunk and not kinked and replace them. I realise that you have said before that you have  checked them but if it is mayonaise type gunk it is hard to clean it out properly and replacement hose is cheap.

Think my new fuel cap is possibly due today, so if that turns up i'll sort that out for starters.
And i'm gonna use a pipe from my CarbTune kit with a can of compressed air and fix it to the metal vent nipples underneath the tank and blow air upwards and see if it comes out okay at the top.
On my bike the tank vent/overflow nipples are lowered into a rubber cup to avoid kinking issues, so the hoses that run downwards from that cup should in no way be kinked as i've never needed to displace them but i'll most certainly check if they're gunked up with anything. On earlier models they do have pipes coming off the tank which i know were prone to accidentally being kinked, if not routed correctly or pulled downwards when the tank is lowered. 

[darrsi]

So the vent and overflow pipes were all good. I pushed some air through them from the 2 metal pipes at the bottom of the tank and air flowed freely, plus the rubber hoses that run down from the rubber cup under the tank were all clear as well so no excuses there.
New cap arrived as well so that's now fitted.
On the old original cap it had a plate with a pin hole that lowered specifically on to the orange rubber housing. The rubber housing covers the breather pipe that goes straight through the tank from top to bottom, and protects it from any fuel going down it.
The replacement cap doesn't have that plate, so if anything it will now have access to even more air.
If there was any lack of venting then it will be inside the cap mechanism itself, so now i've got a shiny new one i can rule this out if it ever plays up starting again.
Won't really know now until it's sat outside work all day again, which won't be 'til next week when i go back, so i'll be back if it ever doesn't start.  :thumbup

[darrsi]

For anyone who doesn't know, the lower hole is the cap breather that goes straight through and gets covered by the orange rubber cap.
And the hole to the left is the drainage hole for excess fuel, or any water that may leak through.

The rubber gasket was in very good nick so i just cleaned it up and swapped it over.

[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]

[quote author=darrsi link=topic=21819.msg253471#msg253471 date=1487878352]
... 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.
[/quote]


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?  :lol

[slappy]

[quote author=fazersharp link=topic=21819.msg253482#msg253482 date=1487880913]
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?  :lol
[/quote]


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  :guitar      :lol

[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  :lol

[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 .