EVO Sportster Engine OIL PUMP "UP-DATE"

[BUELListic]

As you may or may not know the 2007 XB engines got a new up-dated oil pump PN 26357-07(BMC) which will retro fit to older EVO Sportster Engines, BLAST engines(uses the HD PN 26204-91A), and older XB Engines ...

It has been basicly up-dated as was the PN 26204-91(HD) which was used in BUELL EVO Sportster engines to 1997 which was up-dated to PN 26204-98(BMC) and the HD EVO Sportster which up-dated in 2000 to PN 26204-91A(HD) which is the same a the PN 26204-98(BMC) ...

No more could be gotten out of this design, so in 2008 the XBRR design oil pump was used ...

In EVO Engine PRODUCT IMPROVING
LaFayette
Ljenne73c@verizon.net

[Phillthy]

So what is the major change other than the numbers? Better gears? Higher volume? Bigger price?

[aswracing]

They made the scavenge section bigger and the pressure section smaller.

[Don Burton]

Originally Posted by aswracing

They made the scavenge section bigger and the pressure section smaller.

Yes, I've seen pictures of the larger scavange gerotor and the smaller pressure gerotor on the 07 Sportster oil pumps. I wonder what effect that smaller pressure gerotor has on the oiling system as far as oil pressure and lubrication are concerned. Wouldn't the engine be getting a little bit less lubrication? It's obvious by the design that H-D is attempting to improve the scavenge side of things and I wonder how much better this pump is in that regard as well. I've never had any wet sumping problems or oil blowing out of my breathers in my 06 bike the way that I ride but perhaps this increased scavenging potential might benefit some others.

[NRHS Sales]

Having a pump that produces a little less pressure at higher rpms is a good thing. Especially if it can scavenge better.

I am planning to experiment with one of these pumps on a customers bike with known oil use problems and see if it makes a differnce. To dat I have not had any complaints with conversions on 2007 and up using oil. That tells me the pump might be helping.

[NVDEMON]

putting the -91a in XL's that are having blow by problems is one of the steps that HDMC is having the dealerships take. It was a running change, after the certain date, that these oil pumps were used. There is still 07 and later XL's with this problem, don't expect too much.

[NRHS Sales]

Interesting to hear you say that NVDEMON.

Can you expand on the 07s and later still having problems?

[NVDEMON]

There is alot fewer that previous years as they have they updated rocker boxes and breathers. The oil pump is not the end all fix though. On the 06 and Earlier bikes just changing the oil pump was not the step that suddenly made the blow-by dissappear. Neither was correcting the ring end gap.

[NRHS Sales]

Same thing I am seeing. There is no one cause that seems to be why these things use oil.

[aswracing]

You know what's ironic? The better the ring seal, the worse the problems with XL oiling. A little crankcase pressure actually helps the scavenging.

We saw it a LOT when using gapless rings. It just plays hell with the oiling.

The oiling system changes that came with the rubber mount were a huge step backwards.