Not really a problem but one I am curious to know about

[Yeldur]

Earlier today I was riding along and my bike started getting coughy and spluttery as if I was running out of fuel (I was nowhere near it) - As I approached a roundabout I slowed down and let off the throttle, and the bike just killed itself, wouldn't start for the couple of seconds that I tried, so I pushed it off the side and tried again after about 30 seconds of looking around seeing if there were any issues, the bike started, ran completely fine no problems. Got told by a friend that when it happens just stick primer on and try to start it because sometimes the fuel in a carbed bike gets eaten up and leaves it without anything to snack on as it was very hot at the time, I tried that when it happened again later and it started up like normal. What I did find is that if I gave the bike a lot more revs from a standstill it was fine, (Not like screaming the bollocks off of the thing) - Just wondering if anyone has any idea of whether this is an issue I need to get checked out or if it IS what I was told by my friend.

Other than that though it was a lovely ride out

[Bender]

as its been hot could it be fuel vaporising in the carb dont know if bikes suffer from this but some cars do, could be sticking float in carb, (presuming its a bike with a carb).

Edited July 23, 2018 by Bender

[Mississippi Bullfrog]

As above or some contaminant in the fuel. If there's some water in the tank for example then that can happen.

A trick for getting rid of water in fuel tanks is to add some methylated spirit. Water won't mix with petrol but it does mix with meths and then the resulting meths/water emulsion then mixes with the petrol enabling it to be burnt without causing the engine to cut out.

Or of your don't fancy that simply buy some petrol with ethanol content - it's beginning to be sold in the UK (which causes problems for classic car owners as the fuel systems aren't made for it) - that already contains a percentage of alcohol in the fuel so it's cleanse the tank of water droplets.

[BIKERDAD]

I had that problem with my bike and I got a m8 who used to suicide jockey in London (despatch rider ) and he said to me start the bike let it tick over and turn off the petrol let it run dry . The once its dies . Wait a minute then turn petrol back on start the bike . Did this and its never done it since runs like a dream. . That if you can do this on your bike ..

[fastbob]

A wild guess based on my recent experience. The vacuum hose to your fuel tap is kinked and just about to close up altogether. The heat probably makes it worse . Easy to replace .

[Guest]

.....or blocked fuel filler vent. When it cuts out, does it "hiss" if you open the filler cap? If it does, then as you use the fuel, a vacuum is forming in the tank and the fuel won't flow out.

[fastbob]

On reflection, I would say that rather than fuel starvation , you might be experiencing flooding due to a stuck float valve . This will also cause your engine to splutter and stall . If you get it going again and rev the engine this will cure it temporarily by burning off the excess fuel . Best solution is to inspect the float valve seat and look fore tiny particles of debris . Also replace the rubber needle if it shows any sign of wear . An inline fuel filter might not be a bad idea. Sometimes just draining the float bowl and allowing fuel to flow through the open valve will be enough to cure the problem .

[Guest]

I have seen this behaviour before although it could be caused by all the problems mentioned in the helpful posts above, mississippi bullfrog is aligned with my thinking.

Sometimes filling stations dispense dirty or contaminated fuel. This causes temporary fuel starvation. I wouldn't be surprised if this is the issue here. Thankfully it is rare and if this is the true cause no mechanical problems exist. I would therefore assume it to be a dirty fuel issue and see how it goes unless and until it becomes a regular issue.