Ariel Owners Motorcycle Club

Having not started the engine for maybe a couple of years, been in storage, I kicked it up and it started ok, initially it ran fine at both low revs (tick over) and at high revs (throttle well open) but after a while, although it still runs fine at low revs, when the throttle is opened up the engine splutters and dies. At this point the only way to keep the engine running at the higher revs is to fully close the choke.
Note, I have cleaned the carburetor and fitted a new spark plug.
Can't decide whether it is a carburation or ignition problem, any help would be much appreciated.

John P.

How is the fuel supply? Filter at the petcock? Vent in the tank cap?

Almost certainly carburation as it improves with choke, usual stuff, check the fuel supply, strip and clean carb

hi it sounds like fuel , i would start with the fuel tap and tank and fuel pipe i have known the fuel pipe to collapse inside and stop it getting enough fuel , and then check the carb like Roger says

Crappie in the carb

Admin note:
Merged duplicate topics (in case anyone wonders....)

Non-Admin note:
If playing with the choke makes things improve that indicates carb issue (blocked jet even after cleaning?)
However, might be worth checking that the HT brush pickup (and the armature track) are clean.

SG

Thanks for all your input.
Have now proved that there is no petrol supply blockage to the carb., have made and fitted a viewing window into the float chamber, see pics, the petrol level stays constant when the engine is running. Will now attempt to eliminate any other possible causes.

John P.

The problem might be too much air, not too little petrol.

What sort of ignition system does it have - magdyno or electronic?

The ignition is via magneto to my knowledge it as never been refurbished. My reason for thinking that it may be ignition is that a weak spark may more readily ignite an enriched petrol mixture ie with choke closed rather than a weak petrol mixture ie choke open.

John P.

If the mag has not been rebuilt in a long time, get it done as it will let you down at some point. Mags are very reliable but only when in good condition.