Central Oil Tank Sludge

OK, how do you guyz that have the central oil tank (68-70 non FB) get the grunge out of the bottom of the tank when changing the oil. I've never come up with a good solution for this, plus the bike leans the wrong way on the prop stand. I was thinking of maybe putting a shotgun mop in there and soaking it out, but that sounds like a lot of work. Also thought of washing it out with a lot of mineral spirits or similar, but the screen seems to hold a lot of it back. Maybe soaking it with the mineral spirits and blowing the dickens out of it with the air gun and no screen? It's a mess, no matter what you do. I just hate that grunge that collects at the bottom of the tank and I'm sure it doesn't do any good for anything.

Dave
69S

The rag mop trick and pulling the screen out for flushing is messy for sure...........patience and easy on the compressed air if used for less of a mess......

Tim_S

Not sure about central tanks. Too hard to remove from bike?
I just remove mine, Plug all the holes, pour gas in there and shake the dickens out of it until it pours clean.
Pouring solvents in there while it is still connected to the oil lines is not a good idea as the solvent could go down into the timing chest via the oil pump.
Talk about wet sumping, no?

http://www.ebay.com.au/itm/Laser-3659-O ... 33766696e6

Get the oil hot and suck out with this extractor, you'll be surprised with how much crap comes out.

Will also work on your pen%s pump fittings.

Dave you asked, and there is your answer! I have the side mount and every season just pull her off and flush the old school way. But that vacuum sucker would be a ripper addition to the shed tools huh. There are cheaper chinkonesse little electric pumps, for dragging oil from sumps, but I gave up with them, more messy than just draining. A Harley trick is to do what they call a 1 gallon oil change. It goes like this, do your oil change as normal, after you have cleaned your tank, then fire her up with the return line feeding into a bucket, scrutinize it until clean oil comes out.

Cheers Richard

Removing the tank is not easy, I'm not sure it would come out even if I took off the air filter and carbs. It's raining all week, so I'll play with it. If I could get a large hose on the bottom port and keep flushing it.....

Dave
69S

Oh my yes a bugger to strain at removing and reinstalling but should be done by all owners that ain't beefed up the bottom support by upgrading the factory cracker version. I'm of the school of leaving sleeping mean dogs alone, as half fast cleaning with solvents or some probing is more likely to leave what's left prone to entering engine once hot and shaken down the road. By far most the volume of sludge is metal dust not hydrocarbon varnish that cements it in place. Tank out in hand for full attack with objects shaken with solvents &/or detergents and probes is the only way short of taking to a boil out shop. The vacuum idea is good for getting out the residual oil if that mattered a whitworth in the over all volumes. Oil filters only remove the stuff that might clog passages not the particles of size the cause surface wear and sludge layers.