SmedSpeed XS650


sump filter kits

The Yamaha XS650 has a very robust and well-designed engine capable of high mileages. However the designers missed a trick with the oil filtration system, which can only be described as archaic. In 1969 when this design was being turned from the paper stage into metal, it was commonplace within the automotive industry and indeed within some of the British bike industry, to have a replacement cartridge type paper filter, just like all modern vehicles now run. However they elected to fit a brass gauze, similar to the item Triumph fitted. This gauze, as a filter design, is a disaster.

The brass gauze within the sump (picture below)  is renowned to break, allowing unfiltered oil to enter the oil pump. The unfiltered oil then damages the pump body, before finding its way to another equally useless gauze filter located in the clutch cover.

Old worn filter

Engine longevity is a function of good lubrication, and part of this entails keeping the lubricant clean and free from items that will act as abrasives. If the dirt that is produced as a by product combustion is not filtered from the system, the oil becomes a transport for wear inducing carbon and metal particles.

I often have the unenviable task of telling customers why their engine has worn  so badly. Pictured above is a filter I removed recently (yes, that was in an engine!). Whilst it will stop pieces of clutch spring, and other large detritus from entering the oil pump, that is about all.

However it is not the large pieces that do the damage to the bearings, although a lump of anything hard will not do them much of a favour. It is the small abrasive particles that are continually floating in the oil  and being passed through the hardened steel bearings and pistons etc. Although only the coarseness of 1200 wet and dry, if you go at it for long enough, it will wear the big ends and mains away. By far the most expensive part of an engine rebuild is the crankshaft. Modern paper type oil filters are designed to remove all particles down to a 5 micron size (about a fifth of the thichkness of human hair). They are not overly restrictive, and are used on every vehicle in current production.

Sump Filter

The modern cartridge filters available today, coupled with frequent oil changes, will reduce wear to a level commonplace within engines designed today. The SmedSpeed filter is fitted on a modified customer supplied sump plate, and protects the whole engine, including the oil pump. The filter I use is a Yamaha type motorcycle filter, the filter sits at an angle to the ground and thus reduces the ground clearance by only 25 mm, from the original sump plate and surrounding dome head nuts.  If you purchase this item, the fitting instructions are detailed on the 'Downloads' page on this site. The filter MUST be primed.

Sump Filter
Contact me for more details

These are experimental parts intended for racing and as such no warranty is given or implied. If you decide to buy it is on the understanding that you assume complete responsibility for any possible injury, loss or damage that may occur as a result of using these parts and that you accept these conditions of sale prior to purchase.