Oil Pump

[JW113]

Dumb question, but I gotta ask anyway.

Will an EVO Sportster oil pump work on an Ironhead?

thanks,
JW

[aswracing]

It's a pretty common swap to put a 5-speed XL (i.e. 1991+) oil pump onto a 4-speed Evo XL (i.e. 1986-1990). This thread shows how to do it: http://xlforum.net/forums/showthread.php?t=1977681

How much the Ironhead pump setup differs from the 4-speed Evo setup, well, it's been more than 20 years since I owned an Ironhead, and I don't recall.

But look at the pictures in that thread. If your pump setup looks like the 4-speed Evo, the same conversion to the 5-speed pump Evo pump may very well apply.

[JW113]

Interesting, and thanks for that info. Looks like a project for the next time I have the motor out of the frame. The big difference I see is that the Ironhead has the filter in the tank, not routed externally. Need to give that a think.

cheers,
JW

[aswracing]

Also, the 5-speed pump has gone through 4 different iterations. Still the same part number however (26204-91A).

The first version started in 1991 and went through 1997. Some very early 1991 models actually used the 4-speed Evo setup though.

The 1998 revision was the big one. The pump got a longer body, and when you buy the pump from HD, it comes with longer screws in case it's going onto a 1991-1997 bike. The longer body was to make the scavenge side bigger.

Also in the 1998 revision was a scavenge side inlet in the cam box, around the neck of the pump body. At the same time, they stopped drilling the cam box oil drain in the right case half. So all oil in the cam box started getting pulled directly into the oil pump, rather than draining into the crankcase and then getting pulled up into the oil pump.

These 1998 changes were largely because the Buells, being higher rpm, were having more issues with wet sumping than the XL's of the day.

The porting in the pump body got some minor improvements in the 2001 time frame (it was either 2000 or 2001, I forget exactly which year).

Then in 2007, the scavenge section got bigger again. This was because XL motors all got piston oil squirters in 2004, and it aggravated the wet sumping, which has always been an issue on these motors but the squirters made it worse. They didn't make the body bigger, though. Instead, they made the pressure side smaller, although they claim no loss in pressure side capacity. Here's a slide from the 2007 dealer meeting describing the changes:



When you buy a new 26204-91A oil pump from HD, it has a date on the outside of the box. All the pre-2007 versions got flushed out of the system a long time ago. But do check that date, just in case you got some dealer's obsolete inventory.

[JW113]

Again, great info!

So is it safe to say that fitting a 5 speed pump to an Ironhead, regardless of the year, is about the same amount of modification, and that the post '07 version is the one to use?

thanks,
JW

[aswracing]

I'm really not knowledgeable enough on Ironheads to say that any given modification is applicable to all of them, if that's what you mean.

But I will say that the 5-speed oil pumps, all 4 versions, are better than the 4-speed pumps as found on 1986-1990 models. And of the 5-speed pumps, the 2007+ version is the best.

I was digging around in my files, and found this picture from 2000, of the underside of a 1983 XR1000 Bonneville motor I was involved with way back when. The XR1000 was an Ironhead below the cylinders, other than the cams, and the connecting rods were a different length as well, if my aging memory serves.



It has a 5-speed pump on it! So apparently I did the retrofit you're asking about. I didn't even remember that little detail until I found the picture.

This ain't the stock plumbing, obviously. Let me see if I can describe the mods.

On the scavenge side, I have a hose from the bottom of the crankcase up to the pump, and I remember I drilled and tapped that area of the pump for a fitting. Why exactly I did that, I can't remember. I would say look at your motor and see if there's a scavenge port through the crankcase back there, behind the pump, and if the 5-speed pump aligns properly to utilize it. If so, you probably don't need that hose. That may be something I did just to give it an easier path.

The pressure outlet is directed straight up, into the motor's oil inlet on the underside of the cam box. If you're familiar with oiling of that era, it goes from there into the cam box cover, where it goes up, feeding the pinion shaft and the lifters. This bike didn't have an oil filter. You should be able to do it the same way.

Those hoses at the front are draining the top end and cam box into the crankcase, below the windage tray. That's better than draining where the flywheels can stir up the oil and cause drag. I probably also plugged the internal drain for the cam box into the crankcase. You don't need to do any of that.

So basically, all you for sure have to do is just run the pressure side outlet straight up as shown. You *might* have to do that hose in the back, that connects the bottom of the crankcase to the scavenge inlet, but I kinda doubt it.

Just an FYI, I didn't come up with these mods. Ron Dickey (Axtell) was a sponsor on the bike and he advised me heavily. He and his buddy Danny Fitzmaurice (Zipper's) have a lot of experience with racing Ironheads. I think these oiling ideas were from back in those days. I don't think it's too big of a speed secret anymore 

[xlfan]

Dumb question, but I gotta ask anyway.

Will an EVO Sportster oil pump work on an Ironhead?

thanks,

JW

It will work on 77-up iron heads.