Forum

[sofiaspin]

Help needed as I on a long trip on my 500cc classic Elec Start bullet and the bike is fine at speed in fact runs beautfully. But it cuts out coming to a halt at traffic lights or pulling in to a petrol station, unless the revs are maintained. It then will not start until it cools down - but will start with a new plug (champion N3c). We set the needle to the mid-point as it had been mistakenly set to lean, and the of the centre plug is grey and the outside is black - so almost right. The air screw is at one turn out rather than the recommended one and a quarter turns. It pops on the overrun very slightly, suggesting slight leanness. It has a new coil and condenser. Points are fine. Bike has 6000kms on it. Any thoughts on what might be causing this 'shut down and inability start' once it is hot? I have ordered new plugs from our hosts but they will take a couple of days to arrive in our remote location.

[jaffa90]

Have you tried removing the spark plug when it won`t start to see if it`s wet with fuel or dry? How are the tappet clearances?

[jaffa90]

Also (Starts with a new plug)it could be a weak spark so what`s the battery voltage when it won`t start and when it`s cold.A good battery can recover voltage (amperage really)after being low.

[PeteF]

Check tappets first. After that check battery is giving at least 12v under load. Sounds like it could be the condenser. Just 'cos it's new doesn't mean it's OK and a failing condenser often give up when it gets hot.

[sofiaspin]

Thanks guys we are pretty sure it is ignition related after various checks. I have a new coil and condenser with us so we will replace them as a first attempt. Came back tonight and the bloody back tyre has a puncture and guess what, nobody fixes punctured tyres in Ullapool!

[jaffa90]

You NO answer questions.What checks? If you cannot repair a puncture you should not have a modern 1950`s bike.

[Alan R]

Hi guys-------------- I use SLIME with great success.. Also, our hosts stock item No.98090, "Puncture repair kit with air"---------------(ARTHUR please note my balanced posting !!)

[sofiaspin]

We fixed the puncture. Jaffa if you have nothing constructive or relevant to say about the technical problem then do not post comments on my forum questions. Good man.

[jaffa90]

You come on here for HELP then reply with a CONCLUSION and checks made.Also my advice was/were both constructive.Also you still no answer questions.Your conclusion good man is correct.

[Frank]

Not convinced about the ignition theory. I would have thought any ignition deficiency would manifest itself across the entire rev range, may be even more so under load. Sounds more like a weak mixture problem to me. Carb setting, air leak, blocked jet etc. Putting a new cold clean plug in may produce a stronger spark just enough to light the weak mix, fooling you into thinking the root cause is ignition related.