They don't like it up 'em Mr Mainwaring!

lawrence · Post by **lawrence** » Tue Mar 08, 2005 9:16 pm

Now I understand this wet-sumping malarkey. I haven’t been able to run the 650 for over a week and went out on it tonight. The oil had wet-sumped all away so I ran it for a couple of minutes but it still looked low. I topped it up by a couple of inches and off I went merrily. After five miles the bike started coughing and struggling. I checked the oil and it was well over the return hole. I ran some oil out thus ensuring the verge will not rust this winter and restarted the evil beast, still spluttering and coughing (bike, not me). After half a mile it was running perfectly again and did ten miles without a further hiccup.

What I don’t understand is why would the surplus oil level affect the running? The oil must have got into the cylinder but how? The engine appears nice and oil tight (for a Brit). I am puzzled! Who can tell me the mechanics of this???

Lawrence [}:)]

itma · Post by **itma** » Tue Mar 08, 2005 10:47 pm

did you have a look at the plugs lawrence?
even on a new engine some of the excess oil in the sump will get squeezed back up past the rings and onto the plugs. the bore isn`t air or oiltight

Charles · Post by **Charles** » Wed Mar 09, 2005 8:17 pm

If the oil had totally filled the sump, or even more than half filled it, it sometimes leaks into the primary chaincase either via the pressure relief valve in the crank for a dynamo crank or I believe direct through the bearings on an alternator crank (might be wrong on that). After running it up and being 'missing' oil in the tank, the missing oil was probably in the chaincase.

If the chaincase gets overfull, it normally spews out at the sliding circular plate where the gearbox shaft passes through. Great for anti rust properties on the rear nearside and lubricating the drive chain just to make sure it gets spread everywhere.

I'd check the chaincase too Lawrence and drain any excess.

Charles

lawrence · Post by **lawrence** » Wed Mar 09, 2005 8:17 pm

Ah yes. That would do it. Thanks Ken.

Lawrence [}:)]

lawrence · Post by **lawrence** » Tue Mar 22, 2005 10:30 pm

Yikes, where did Charles post come from????

Thanks for the info Charles. I will check that.

Lawrence [}:)]

pwaltham · Post by **pwaltham** » Wed Mar 23, 2005 1:37 pm

Lawrence
Despite all previous forum comments about anti-sumping taps I fitted one of Mr Doves taps to my model 31 a year ago and, dare I say, its idiot and fool proof.
So long as you wire it up decently and check the wiring (as you ought to for the rest of the bike) there is little chance of riding off with no lubrication.
Checking time has to be less than all the times you would have spent draining the sump after a period of standing, and you can see instantly whether the oil level needs topping up.
I await others comments or has it all been said previously
Peter[}:)]