Bike won't start/cuts out

[snikks]

Hi All,

So, I head out to the garage this morning, give the bike a swift check-over, unlock it and wheel it out. Choke on, start it up, and leave it to warm whilst I get the rest of my kit on.

The bike was idling at around 2k rpm, which is fairly normal for with the choke on, usually struggles a little then as it warms gradually reaches 3k rpm, at which point I can choke off and ride, taking it a little easy at first of course. Not today however, I turned to put my helmet on, turned back and the bike had cut out. At this point it'd been running for probably a minute.

So I go to restart it, nothing, the starter sounds to be turning it fine, but it won't catch. Try switching it off and on again (can you tell I'm used to working with computers?) no difference.

After prolonged testing, I can verify that the bike will start and turn over a few revolutions before cutting out if I:

Turn the ignition on, turn the choke on, don't touch the throttle, and press the starter. This gets me about 2-3 seconds.
Turn the ignition on, leave choke off, give a little throttle and press the starter - the bike will start and by giving more throttle I can keep it going longer, about 4-5 seconds up to about 2k rpm, before it will again cut out.

All the facts I can think of to list are:

When I first turn the ignition on there is a small "buzz" sound that I'd never worried about. However this seems a little louder than normal to me.
The engine when it does run, sounds "clunkier" is the best way I can put it. Not smooth like normal at all.
The oil level looks okay (although the oil is a little dark, I'd been procrastinating changing it).
The coolant level looks ok although I can't see it hugely well without taking a side-panel off. I did have a problem with my radiator leaking that I previously posted about, but that seems to be solved and the point that was leaking before is definitely dry.
I've tried flicking the sidestand up and down, and changing the gears out of and back into neutral.
I haven't tried to bump it, as my driveway opens directly onto a busy main road, so there's not really any space to do so.
The battery seems ok to me, as far as can be told without a multi-meter. The same thing happens with the headlights completely off.

Here's hoping one of you wise bods can point me in the right direction.


Edit: This SEEMS to be fixed now - cleaned up the end of the fuel tank breather as it was caked in road gunk, and opened/closed the tank to check petrol level by eye (just in case gauge was faulty), fired it up again and it started perfectly, just as normal. Took it out for a little ride, just up/down the street as I'm supposed to be working from home due to my broken bike today. Fingers crossed that's nailed it and it was just a minor blockage at the end of the breather.
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- CBT: 02/01/11 Theory: 26/04/11 Mod 1: 19/05/11 Mod 2: 19/08/11
- 2007 Honda XL125V Varadero (Sold), 1999 Yamaha FZS600 Fazer (Sold), 2001 CBR600F

[CEDR]

Glad you seem to have fixed this, but it sounds relatively similar to a problem (one of many!) my bike is having! Same things in terms of the weird buzz noise and clunky sounding engine. Doesn't help that in addition when I press the ignition it often doesn't do ANYTHING, which when you've stalled in the middle of the road is a bit stressful!

Mine's just a 125 so it seems that if I give it a nudge forwards in Netural whilst pressing the ignition, it seems to be more likely to fire up and start! What a headache!

[bazablue]

a simple thing ..if your petroll cap has a good seal then when after a run or big change in weather temp a vaccuum can be created therefore the carb wouldnt refill...was once a common prob on brit cars...remove cap and release vac u may hear a pop/suck noise....as per blocked breather(which is why you have one)..if I dont start its always the first thung I do and as for the other reply,,,winters coming,if in doubt sling yer battery,not worth plaing with,if good put on trickle charge once a week AND check electrolyte level weekly!!!!!

[bazablue]

a simple thing ..if your petroll cap has a good seal then when after a run or big change in weather temp a vaccuum can be created therefore the carb wouldnt refill...was once a common prob on brit cars...remove cap and release vac u may hear a pop/suck noise....as per blocked breather(which is why you have one)..if I dont start its always the first thung I do and as for the other reply,,,winters coming,if in doubt sling yer battery,not worth plaing with,if good put on trickle charge once a week AND check electrolyte level weekly!!!!!

[stephen13]

hi all i have an aprilla rs 50 electric start i have a problem with the bike it will not start has had new spark plug new battery and fuse box the carb has been cleaned out in the garage yesterday and they still could not get it to start as well any ideas pls thanks ste

[Walloper]

[stephen13]

i have done all that and nothing tried bump starting all that happend was the speedo move to just below 3 rpm also can smell petrol when did this as well and the mph moved a little as well any ideas would i need a new engine

[Walloper]

No Spark at the Sparking plug.

I've known engine to keep running with next to nothing left of the piston rings.
Not very well and very smoky but started an ran after an afair.
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

[stephen13]

there is a spark but very little thougth