intermitant spark on wassell ignition fitted to A65

[pockets]

The spark seem to come and go  at the plugs , crank it over all seems fine then dies off for a few cranks then comes back, have checked connections and all seem sound , bypassed the ignition switch and still has same problem , tested the combined resistance at the sender   wires at the unit plug and comes to 136ohms havent tested them individually , the coil seems ok reading 5.1 and 18k , replaced the plug caps for resistance ones as recommended. cant  do the sender bypass test as doesnt work on the bsa twin setup apparently . Any suggestions?

[DAVE BRADY]

Hi Pockets,

I had a similar problem with a Boyer but the problem was actually in the wires from the pick up and the unit.  There must have been an internal break that intermittently worked/didn't work.  Ironically it was the one bit of the old harness that I did not review.

Dave.

[pockets]

Do you meen between the sender stator and the unit , was it not supplied with the kit ?

[idie]

The resistance on your coil is very high, electronic coils are about .5 ohm or are you reading across two coils designed for points in which case 5.1 is fine.

[pockets]

its a dual plug coil and reads within specs for that coil, think wassell recomend between 3/4.5 ohms , think u can get issues with continous firing if the resistance is to low , but could maybe it does cause issue if to high dont know, but when looking online on ebay the ones they say are compatible with wassell boyer for sale have the same outputs as mine ,

[pockets]

Have checked again for spark and defo sparks for a while , a good few cranks fine then  nothing for up to 7cranks then kick in again , strangs symptoms, have tested the resistance at the stator coil and it stays constant  at 136 ohms even if i wiggle the  sender wires so dont think its that .

[pockets]

Gotta be ignition coil , control unit or stator plate surely.

[EDDIE SIMPSON]

with electronic ignition i always have the earth connection to battery earth. whats yours like?

[pockets]

yes it goes to battery , Ive also rerouted the sender wire as it was running with other wires which can cause problems aparently , still the same , have ordered new ig coil which seemed ok but for the sake of £20 to rule it out thought it was worth getting a new one .

[chaz]

the trouble with coils, past experience on Japanese bikes, is that they run fine until they start playing up. usually as a result of internal damage.
when cold (normal time to check), they are fine but when they get warm they start breaking down.
Two modern Triumphs, first a Trophy 900 starts playing up, middle coil, and the rev counter stops working, second a Speed Triple, coils over heat, solved by using flexible washing machine pipe under the tank to direct cold air onto the coils.
the coils are sensative, so on a Brit vibrator probably not the best thing.

[pockets]

it doesnt run long enough to be effected by heat as wont start for more than a few seconds , but have ordered a new coil to rule it out , seemes fine when tested but maybe has issue under load I supose , if its not that then something wri=ong with the  electronic side of things .

[DAVE BRADY]

Hi,

Re my comments re Boyer.  The fly lead on the Boyer is quite short so an extension was need to exit the timing cover and connect to the magic box.  I have used a twin lead coil mounted on its heat sink for many thousands of miles with no issues.
Have you tried different plugs?

Dave.

[chaz]

Im running the Wassel ignition on the B40, cant fault it. fires easy , better than the bob weight system, if only the carb was more reliable.
I did fit a new coil and its a home made loom so new wires and connectors soldered on, long enough wire but not over long as per their instructions.,  didnt have a lot of luck positive earth, but since changing to negative its fine.

[pockets]

Havent tried different plugs as    they look new .

[DAVE BRADY]

Hi,

You never know so worth a try.  There have been a couple of threads about plugs and some have porous insulators which can get wet with fuel and not spark properly.

Dave.