I don't know about a 'bessie', but I have found in the past that every one I have seen has a standard threaded cap.

I'm sure someone will now come along to tell me I'm wrong. :lol:

To help in the removal have a bowl of water as hot as you can stand and put a towel in the water. when it has soaked in the water take out and put around the top. After a minute or two remove, resoak and put back onto the cap. Now try unscrewing it. The heat should expand the cap and also loosen the lubricant that may have hardened on the thread, and the wet towel will help you to grip the top.

After this if it's still stuck you might have to make a tool that will fit over the cap that you can put a bar through, if access is tight, other than that there are specialist tools like oil filter removers that could be adapted. I hope you can get it moving.

Frank.

 

Had prob with mine ,managed to use a flexible attatchment to drill with a cut down drill bit ,drilled two holes ,inserted two small bars then used a screwdriver as a lever ,came straight off ,,then pluged holes after repair ,,,thats if you have the room ...regards Les

 

It is highly likely that the tank is a CAK tank http://www.caktanks.co.uk/
so you may wish to contact them to see if a replacement cap is available.
If so, and I shall be surprised if not, you then have the freedom to be a bit rough with it if you need to...!
Ours had been sealed with silicone - no idea why but it did make it difficult to persuade to let go.

Patrick

 

Must change my profile, I now have a Hobby 600, 2005.
Filled up with freshwater and water in the garage.
Took up floor hatch and sender unit is causing a leak when overfilling.
Should go out of overflow.
Dealer is going to fix it, along with a couple of SMALL other items but I like to be in the know, and was looking at sorting it myself.
The cap IS BLUMIN SOLID, even tried tapping it with a bar and hammer.

 

Thinks me will leave it to the dealer.
Then have a look at what they have done
We off this weekend for two nights, will fill tank with the boss's,miss us keeping an eye ont the cap.
Cheers all.