Cleaning the oil tank?

[chrisb]

Slowly getting my BSA 31 ready to start.  The previous owner hadn't run it for several years.  I've read stories about what might be hiding in the bottom of the oil tank, and equally tales of trying to clean the tank - with mixed results - and possibly doing more harm than good by disturbing what is down there.  So is it worth me trying to clean out the tank, or is it best to let sleeping dogs lie..?
Also, are there any important checks to do before trying to run it for the first time - I want to make sure I don't do any damage (plug looked pretty oiled up but that might be because it has stood a while - and I kicked it over a few times just to see how the decompressor worked!)

[Bess]

Hi,
     Bikes without filters, the sludge settles in oil tanks, areas on the internal cases and in the centrifugal sludge traps if fitted.

BSA recommended periodic cleaning of the oil tank and screen filters. I guess the if these items are inadequately cleaned you could possibly have mixed results.

Best wishes...

[Dean Southall]

My feeling is that it is worth cleaning if you can/have the energy to get the tank off the bike to give a it a proper wash out with parrafin/petrol and triple check it is spotless before re-installing it. If you can't be this though its probably safer to leave the settled out nasties to rest in peace rather than dislodge them and put them back in circulation.

[chrisb]

many thanks.  Will drain the oil and see how bad it looks inside first.

[DON GRAY]

I'm lucky to have access to some small, very strong rare earth bar magnets - Scalextric cars if yer can rob em!... & following a complete strip & rebuild of my B44 engine & subsequent thorough flushing of the oil tank,  have simply wired one of these to the dipstick as a safety measure. So, yes do flush the tank & filters till you get em clean. In use the magnet gets a light black coating after a few hundred miles that wipes off on a rag. Saves filling up the sludge trap!   

[chrisb]

many thanks.  If I can't find a scalextrics car "spares or repair" on fleabay(!) - do magnetic sump plugs do a similar job?  What's the best  thing to rinse the tank out with?  I want to minimise risk of damaging the tank paintwork..

[Bess]

Hi,
    The magnetic sump plug will do a similar job and are readily available, I've fitted them to all the bikes I've had in the past with success.

I have used petrol to thin the sludge and then pressure washed the inside, thoroughly drying afterwards and the tank was pristine afterwards. It was interesting what I removed from the inside and relived I took the time to ensure a clean tank. I've never done this to a tank in place but if care is taken I cant see the problem. If you buy a SRM oil pump their recommendation is to thoroughly clean and dry the tank ideally with a pressure washer before fitting the new pump. I guess if its good enough for them its good enough for me.

Best wishes...

[Andytj427]

I'm restoring a C15 and have just cleaned the oil tank out prior to repainting. I didn't think it would be too bad as the oil looked quite clean when I drained it. I was wrong. The bottom of the tank was full of thick black sludge and once I'd rinsed it out with petrol I was left with a residue of fine grit in the bottom. I ended up washing thoroughly with hot soapy water (washing up liquid - yes I know it has salt in it!) and rinsed with loads of hot water. Thankfully the British summer's been kind and an afternoon outside dried it out nicely. Now to see what's left in the engine & sludge trap  ........

[nickdun]

Has anyone tried caustic soda solution?  Followed by a thorough rinse of course.
Nick

[chrisb]

thanks for the advice.  Think I will bite the bullet, take the tank off and give it a good clean.  I guess it is just held on with a few bolts from the rear?