dyna coils

Hello guys from sunny England
need some advice my A1 runs sweet for about 5 miles but then sort of stutters and dosnt rev cleanly , carbs have been cleaned numerous times and i am happy they are set up correctly, the valves have been shimmed my gut feeling is coils.
at the moment i have dynas and have recently replaced the leads but the actual coils have been on the bike at least 10 years, is there a simple way to test them, as mentioned problem usually occurs after approx 5 miles
many thanks
Paul

You might want to check the vent under the filler cap sometimes if it gets blocked or the seal moves it will stop the bike from running right after a short while (it happened to me bike just died

Thanks for the reply, never checked the vent so will try that in daylight, is it obvious which hole needs clearing?

An easy way to check the venting issue is to open the fuel cap when the bike starts to play up. If the bike runs normal again then you know it's a fuel flow issue (probably best to make sure you are not moving when you try this).

Speaking from experience, having an open gas cap will cause the slipstream to suck the gas out of the tank and spill it directly onto your balls. :woohoo:

Check your battery terminals and make sure they are connected securely. If you still have the fuel solenoid connected loose terminals may cause the fuel delivery to be intermittent when you hit bumps and such. I had this problem and the engine would start and rev very nicely while stationary but as soon as I was traveling it would then splutter and cough - fuel solenoid needs power.