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Oil sump

Posted: Tue Mar 26, 2024 3:52 pm
by Vink27A
Has anyone experiance with the quantity of oil which is sumping into the crankcase after 6 months on its side stand?
We I start the engine it spits quite some oil out of the breather for a while.
Is there a possibility to include a ball valve to prevent draining?

Re: Oil sump

Posted: Tue Mar 26, 2024 6:36 pm
by SPRIDDLER
It's fairly common. There are several threads on this which you can find if you put Wet+sumping (without any spaces) into the Search facility.
In short, when the bike has been left for a while and wet sumped it's necessary to drain the oil from the c/case, otherwise you're likely to get clouds of smoke and an oiled-up sparkling plug. If left on the side stand it may be necessary to drain the excess oil that has spilled past the main bearings (which have no oil seal) and into the primary chaincase.
A ball valve isn't ideal since the low pressure reciprocating plunger type oil pump (as opposed to a rotary pump) moves the oil in a series of bursts rather than the higher pressure and continuous flow of a rotary pump (as fitted to the twin cylinder engines).
Some owners fit an 'anti-sumping tap' in the oil feed line but it carries the risk of forgetting to turn it on unless you fit one of the type that cuts the spark when turned off.
I've pulled off the plug lead whenever I've turned off the oil tap. Some put a brightly coloured strap or cord reminder from the kickstart to the handlebars.

Here's the pump action........
Oil pump action..gif

Re: Oil sump

Posted: Tue Mar 26, 2024 7:06 pm
by dave16mct
Also always leave the bike on it's centre stand and turn the engine with the kickstart on to the compression. This leaves the engine in the best place to prevent wet sumping.
Dave

Re: Oil sump

Posted: Tue Mar 26, 2024 7:16 pm
by Steve
last Monday I managed to get mine uncovered as it lives outside, and had an awful job trying to start it lots of gurgling sounds and it wouldn't start.
took the sump plug out the next day and filled a jam jar, started after 4 or 5 kicks, its never been an easy starter.

as for a tap I've not fitted one but I have fitted a thorspark electronic ignition which I had to fit a switch that I fitted to the left hand kidney box
however in that position I would forget to either turn it on or off, (out of sight out of mind)
so I have now fitted a switch on the handlebars easier to see. (I'll probably still forget it Ha Ha) so the point of this rambling is if I were to fit a oil tap I would go with the electric option, as the worst that would happen is the bike wont start. and after an hour of kicking it over your realise you've forgot to turn it back on. :rofl:

Re: Oil sump

Posted: Wed Mar 27, 2024 10:41 am
by Vink27A
Thanks a lot for the good comment.

Re: Oil sump

Posted: Wed Mar 27, 2024 1:18 pm
by Pharisee
dave16mct wrote: Tue Mar 26, 2024 7:06 pm Also always leave the bike on it's centre stand and turn the engine with the kickstart on to the compression. This leaves the engine in the best place to prevent wet sumping.
Dave
Sometimes, perhaps, maybe... With a two start worm, it take 8 complete revolutions of the crankshaft to move the oil pump through one complete cycle. That's four compression strokes, so leaving your particular engine on compression, the oil pump can be in any one of four positions.
The oil plunger has 16 teeth, so it can be mated to the worm in any one of 16 positions when it was last assembled. You can see that's a lot of different permutations of oil pump position relative to compression stroke. But hey... if it works for you, that's fine :D :D

Re: Oil sump

Posted: Wed Mar 27, 2024 3:29 pm
by dave16mct
It does work for me and it also leaves the valves closed and the valve springs relaxed. I also leave my twins on compression which makes no sense at all but it seems to work. I wonder how many others do this?
Dave

Re: Oil sump

Posted: Wed Mar 27, 2024 10:24 pm
by Yak
Hi
I leave my G3L on compression mainly for the valve springs. It wet sumps only

very occasionally even over longish periods so it appears the pump lines up on a worn spot from time to time.

Re: Oil sump

Posted: Thu Mar 28, 2024 2:12 am
by Expat
Same here Yak.

Re: Oil sump

Posted: Fri Mar 29, 2024 3:33 pm
by EddieDay
Steve, my M18S had an anti sumping tap on it when I bought it. I was also worried I would forget to oprn it before riding so I fitted a red tab to it. It would be difficult to kick start the bike with the tap in the closed position. You can see it in this photo.