650 Central has started producing a sump extension kit. MCEN40-2750. You wont find it listed yet.  A serious performance modification. 2 3/4″ deep (69.85mm).
Lowers the oil level freeing up the flywheels and clutch basket. Less flywheel drag implies better dyno numbers and lower oil temps.

Kit price … $135.

• extension-(cast for better heat dissipation),
• SS bolts
• 2 gaskets

 

 oil sump kit

 

Hattip Alvin.

650 Central … Mike “Mercury” Morse …

“To race is to live—all the rest is just waiting”

Was asked yesterday about sump extensions. Do they exist? Who makes them? Are they effective?

I know of 2 suppliers. Ivan Hoey in Australia advertises his on the Australian XS650 site. Racers Bits. Scroll down.

 

Ivans sump extension

 

And Twinsinn in Germany. Go to ‘Shop’ and then to ‘Ölfilter, Ölpumpe…’. Scroll down. Part number Öl042.

 

from Twins-inn in Germany

 

This requires removal or repositioning of the side-stand for models later than ’76. But has cooling fins. And is a little deeper. I have one of these in one of mine. The other has a sump plate modified for an auto spin-on filter. An extension would make this too deep.

I also have 2 of these. No idea who makes them. One was on a parts bike. The other in a box of bits I acquired from somewhere.

 

unknown european producer

 

I’ve filled this. Takes 200ml. An 8% volume increase. No function loss. Follows the sump plate contour. Fits with the sidestand in place too. Weighs 220g.