Here’s one for the electrical wizards
My mates ambassador is refusing to fire up after the winter layoff.
Battery ok, power to the coil (now replaced in case that was the problem) spark at the points (although it doesn’t look too bright) new points and condenser, tried both before and after.
Nothing at the plugs, have had a close inspection of dist cap and no cracks, replaced ht lead dist to coil still nothing
Any ideas???

New plugs as imediate action in any no start situation.Then check earths between engine and battery. I run an earth lead from the starter motor bolt to the battery -ve.If your +ve side is OK then the fault must be in the -ve.

iandunmore2013-07-09 15:50:08

Ian, surely the Ambo is negative earth? Good idea to check the earth connection from battery -ve to frame, the plugs might not be earthing properly.G.

Typo corrected.If the Ambo has a large undertray battery collective bolt then strip and clean it thouraghly.Never worked on anything with a dissi so no help at that point.

Try putting the HT lead up close to the engine and spin it over, see if you can get a spark from the bare end of a lead.
Any daft cut outs, kill switches on this model or does it predate such items?
Are the new points asembed correctly so one part is isolated from the engine? Does it spark if you open / close the points manually?
Are you getting voltage to the coils?
A few starters.

"Let’s start at the very beginning …

It may JUST be a loose or corroded connector BUT which one…Ahaaaa

Start at

The Battery …check the Voltage , the connections take them off and check for corrosion …check the earths

Follow the Lo batt feed to the dizzy/coils pull and check each connection OR the Volts at each one in turn

Check the ign switch feeds

IF there is power to the dizzy then the coils and NO HT then coils are suspect

Be aware there can be faults in plug caps and plugs BUT if it ran before then it should be all good

OH yeah sometimes a spark is not that visible a carbtune may help or the old fasioned “apprentice” check method

You know the one? " Ere lad 'old this" … give HT lead to hold a yoof will ALWAYS lean on something…like the bike frame Then hit the starter…

You will quick soon know if there is a spark there

Erm there IS fuel and it IS getting through? modern fuel is utter rubbish and real good at blocking fuel taps let alone carbs

try fresh petrol
it goes off after a few months
my breva rattled and popped after 3 months storage
I filled up with fresh stuff and it ran spot on
also are the float needles sticking after storage ?