SR125 troubles

[badlegbill]

My daughter asked if my grandson could use my little lifeboat bike to run around on until he passes his license some time back.
I said yes and took it up there, about 160 miles on the road.
I've just come back from a few days at her place fitting a complete set of luggage on her CB500X and was told the bike, the 125 ,was playing up and died after about 10 or 15 minutes use.
I've ordered a new replacement coil because stripping cleaning and resetting everything to factory including a fuel flow test, open carb drain plug into a container, and level, why do boys have to play with things they don't understand, did not affect the issue.
The plug looks OK, that is not fouled enough to be the problem, so I am guessing weak spark, swapping out the coil makes sense since the wiring checks out and the running voltage is around 14v.
Does anybody have any experience with failing igniter units or have a test process to eliminate it as a cause?

 

[badlegbill]

Hi everybody, just to close out this thread on the bike of doom.
The bike ran sweetly for a while and then not every time and I cleaned and set the carb put new plug in contact cleaned all the ignition plugs and connections so that on several occasions I declared it fixed. It wasn't, but on a ride back from the cafe it stopped again and I opened the gas cap to check if I had run out of petrol and noticed a subtle whooshing sound, I was inspired to leave it open and ride on as it did have petrol.
Alright I should have noticed it earlier but what sort of d^&khead paints the gascap breather.
It now runs as sweet as it ever did and dependably.
Being smart is no good unless you pay attention.

 

[RC4MAN]

Yep, clogged breather in cap will give you fits. Knew a guy back when Honda came out with the first Shadow 1100, breather was clogged and it actually sucked a depression in the gas tank. Glad you figured it out.

 

[badlegbill]

Eventually, should have checked earlier. I forgot "Always check the basics 1st."
Weirdest similar thing. I had the tank repainted on a Norton once and it wouldnt sustain high revs but would cruise all day. After fitting clear fuel pipe I watched a blasting bead slowly be drawn into the carb stub and limit flow. As soon as demand lessened it would float back up.