Update.

I went to bed last night with my mind almost decided that I would put a new engine in the bike today. But when it came to it sentimentality got in the way and I took the bike on a 100 mile ride, through the urban sprawl of Bamako and into the desolate Mali countryside, and it never showed any signs of trouble. I've decided I'm going to keep the bike the way it is and take it to Burkina, but if it becomes apparent that there are any issues on the ride there then I'll get a new engine put in when I get to Burkina Faso. I can feel confidence in the bike slowly returning, and I hope the constant worry in the back of my mind will fade so I can enjoy the delights of Africa clearly. On today's ride I was invited for a dinner of rice and fish out of a communal bowl on the ground by the guys at a petrol station which used a genuine hand pump, saw numerous trucks with the top compartment crammed with screeching goats, and the best thing... A man riding his bike down a road which had seven lanes of honking criss-crossing bikes, wearing a smart suit with the most content look on his face, whilst he was laying down on his back seat, arms behind his head and steering with his legs. Your never prepared enough to ride on the roads here.