Older Harley-Davidson Engines

Ironheads :: Panheads :: Knuckleheads :: Flatheads


Ironhead Sportsters

This much maligned model, produced from 1957 until 1985, and was not a big seller in the UK during it's production life. The vast majority of Ironhead Sportsters over here have been imported, second hand, from the USA, with most of them coming in during the early '90s.

Many of these were sold cheaply and suffered from bad (if any) maintenance, and, quite frankly, some appalling, low quality rebuilds. Whilst these bikes have been relatively cheap to buy in the past, they are not cheap to rebuild, particularly in the light of the amount of rectification they now typically require.

Since these engines are of unit construction (transmission is integral with the engine cases), then we have to deal with the gearbox and primary at the same time.

We have a large amount of experience with these motors, including strokers (in fact we were heavily involved with building the engine for a nitro burning 96''drag bike which was British Super Twins champion in 1996) and can completely rebuild these engines to a well performing, reliable, standard.

For those enthusiasts who wish to do much of the work themselves, we can undertake just those jobs that require specialist attention such as cylinder boring, crankshaft rebuilding, and main bearing lapping.

We also have experience with the very rare XR1000 and the Cafe Racer variants.

Please note that many of the aftermarket parts for these engines are of very low quality and for this reason we will only take on rebuilds on the understanding that we supply the parts used and that you are guided by our experience regarding it's intended use and the performance level.

Ironheads do not have to be hand grenades waiting for the pin to fall out.

Panheads

Produced from 1948 to 1965, the Harley-Davidson Panhead, while sharing a similar bottom end to it's Knucklehead predecessor, had aluminium cylinder heads, fully enclosed valve gear, and hydraulic tappets. During this era the Panhead also powered some iconic model designations. Telescopic forks gave us the Hydraglide, rear suspension gave us the Duoglide, and the introduction of an electric start gave us the name most synonymous with the Big Twin (which carries on to this day), the Electraglide.

Engine wise, there were also many changes. 61 and 74 cubic inch versions, changes to the oiling system, a multitude of different sprocket shafts and pinion shafts, and a number of different main bearing configurations, as well as the heads. There is some degree of interchangeability between sub assemblies from different year groups, but this also leads to the danger of mismatched parts for the unwary.

These engines are now so old, and often so "got at", that great care is needed to determine what's actually in there. The later the engine, the stronger the lower end became, and by '58 we had the immensely durable Timken bearing set up on the sprocket shaft, and the 1.250" diameter pinion shaft (which used the bearings and cages from the "Star hub" wheel bearings). This arrangement carried over into the Shovelhead era, and with a minor design change, into the Evolution era as well.

As far as performance upgrades are concerned, this is best left for the '58 and later versions, and unless originality is a key issue, an S&S oil pump and a conversion to outside oilers to the rocker gear, gives the best life span to the top end. Because Harley engines evolved, rather than became completely redesigned, there are a number of performance options available, including strokers, heads, cylinders, and camshafts. We are very familiar with the interchangeability of Harley parts, and the aftermarket upgrades available. Because of their age and design, these rebuilds are very labour intensive, and often require some quality machining to get the best from them.

We can also rebuild the S&S P-series engines.

Lapping pinion race of '57 Panhead

Lapping pinion race of '57 Panhead. This year group uses the Ironhead XL pinion bearing rollers and cages

Truing '57 Panhead crankshaft

Truing '57 Panhead crankshaft. This has been balanced by us to suit Keith Black pistons and an S&S rod set. The Pinion and sprocket shafts are Jims Machine

Assembling '57 Panhead

Assembling '57 Panhead crankshaft through drive side Timken bearings using the excellent S&S service tool

Knuckleheads

Flatheads

Honing 45 Cylinders

Honing a new set of replacement 45" cylinders to suit the new standard pistons. These cylinders are deliberately supplied undersize from the manufacturer, to allow for the correct clearances to be achieved.

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