I have an '87 CBR600 FH - UK model, which has a nasty habit of cutting out on me when left to idle after a long run of hi-speed riding.

This usually happens when stationary at traffic lights a few minutes after riding continuously for 20-30 minutes at 75-85mph. It initially idles fine when stationary, but after a minute or so waiting it will sometimes just cut out. It won't restart after this until it has been spun over on the starter for a minute or two on full choke.

My first thoughts are a fuelling problem - so far I've stripped the carbs - cleaned and checked all the jets (including idle jets are clear), new air filter, new plugs, but these haven't solved it. Idling has always been a little rough on the bike when cold/running on choke, but when the bike warms up it is ok.

On a previous bike, an '88 CBR600, the fuel pump failed, and it would cut out at high rpms, and finally woulnd't run at all, but this time I don't think the fuel pump is the problem. (incidentally any forum readers with fuel pump probs may like the know that the early NX650 Honda Dominator fuel pump is the same part number/type as the CBR pump).

Anyone any ideas or experienced the same problem ?

Just to add, the cam chain was replaced about 4k miles ago with a split link version (this solved the rattling caused by the chain stretching beyond the limits of the auto tensioner), and the valve clearances were also checked at this time.