The otherwise awesome BMW R100RS has suffered from an incontinent petrol tap union since it came to me last year. At first it was hard to diagnose even where the continual drip came from but eventually it was traced to dodgy threads on both the tap and petrol tank. For those who aren't familiar, BMW use a tap that has a large diameter internal thread attaching to the external on the petrol tank. The thread pitch is fine and the whole set up is rather delicate, vulnerable to bodgery and cross threading. Mine had indeed suffered both these malaises over the years.
Several unsuccessful attempts to fix had me searching on the net for a solution that didn't involve remedial repairs to the tank and a new tap. The best chance seemed to be a tube of Loctite 565. It's not cheap but I decided to give it a go and a few days later a tube dropped through the letterbox. It's a white paste that is designed as a thread sealant for fine threads, it is non-hardening and was apparently designed for refrigeration machinery. Everything I have read assures that it is petrol proof.
The good news is that several days later the tank is still not leaking, it's full so has plenty of pressure on it and so far seems to be a good fix. From now on Loctite 565 joins the pantheon of dodgy chemicals stored on a rickety old shelf in the workshop and will be relied upon as an elixir for other leaky shed mates of the Beemer.
|Leaky BMW petrol tap fixed.|