Engines


Harley Davidson has manufactured a V twin in various engine sizes and design formats since 1907. The V twin engine is their trademark and is one of the most iconic images of motorcycling, recognised by the faithful worldwide.

Harley 45
Harley 45 engine 1936 - 1978

The Harley Davidson engine generally and usually lasts a very long time between rebuilds. The low revving nature of the engine doesn't suffer the high stresses associated at higher rpm engines, and as long as routine maintenance is carried out they are reliable and long lived. However everything wears out eventually, and when it does we are at hand to help you rebuild it, allowing many more years of reliable service.

Harley Knucklehead engine
Harley Knucklehead engine 1936 - 1947

When the time comes to rebuild the engine, the task is generally not easy. The workshop manuals are quite acceptably written, and describe in detail what you need to do; unfortunately the huge quantity of service tools precludes almost all from doing it themselves.
The procedures and tooling involved take rebuilding out of the scope of most owners, and even some shops. Blueprint Engineering is a dedicated Harley Davidson reconditioning workshop, who have invested considerable time and money in tooling, measuring equipment, and education, to ensure that the correct procedures are used to give your Harley engine a rebirth.

Harley Panhead engine
Harley Panhead engine 1947 - 1966

In addition to rebuilds, we have considerable experience in high performance upgrade work, whether it is for the latest Twin Cam engines or Ironhead Sportsters and Shovelheads. Harleys like any other motorcycle are built to a price and a standard. The carburation of HD models has never been superb, more acceptable than anything. The addition of a good carburettor on any model (excepting fuel injection models) will transform its manners and fuel economy, we can advise on what works and what may not be so suitable.

Harley Generator Shovelhead engine
Generator Shovelhead engine 1966 - 1969

Harley performance tuning for decades relied on fitting a longer stroke crankshaft (a "Stroker"). These longer stroke engines were the byword for performance orientated HD engines for nearly 60 years. The longer stroke made the engine vastly more powerful, even from very low rpm and they are an absolute blast to ride. However too much stroke can reduce the engine life (mainly pistons) and for this reason some restraint must be used when selecting what stroke to use. The maximum stroke any HD seems to be happy with is 4 5/8";, anything above this seems to reduce engine life (mainly pistons) for little in the way of extra performance.

Harley Shovelhead engine
Shovelhead engine 1969 - 1984

S&S made their name in the high performance Harley tuning business from very modest beginnings in George Smiths basement. Now they offer a huge selection of parts, including whole engines. There are literally hundreds of companies in the high performance HD market, many appear offering some "doodad" that your bike can't live without and then relatively quickly disappear thereafter, there are fewer good ones, we can advise on what is good quality and what is junk.

Harley Ironhead Sportster engine
Ironhead Sportster engine 1957 - 1985

Most Harley tuning relies on increasing the cubic capacity i.e. making the engine bigger. The old adage "you can't beat cubes" is an absolute truism in the case of Harley engines. Whilst vastly increased performance is definitely attained by following this route, a healthy increase in performance can be attained for far less expense by adding a good performance cam, a carburettor or a set of well designed exhaust pipes. Blueprint Engineering has much real world experience gained from riding these bikes for 35 years and is happy to advise you which route might be most suitable for you.

Harley Evolution engine
Evolution engine 1984 - 1999

Should the increased capacity route be chosen, a stroker crank is the preferred method of attaining a larger displacement engine on pre 2000 models. The stroker can be extremely reliable and Joe has a bike with an 89inch stroker that has done over a hundred thousand miles. This reliability is not a given however and considerable care and correct procedures including line lapping the crankcases and clearancing everything is paramount if the engine is to be reliable.

Harley Evolution Sportster engine
Evolution Sportster engine 1986 to date

Blueprint Engineering is able to offer the following procedures to assist you in your rebuild or building high performance engines:

Crankshaft and gearbox line lapping
Rebore and honing
Valve seat cutting and valve seat replacement
One off manufacture of valve guides
Squish clearance correction
Crank shaft balancing
Bead blasting, wet and dry
General machining
Specialist machining
Valves manufactured
Welding on aluminium and steel

Harley Twin Cam engine
Twin cam engine 2000 to date

There is little in the way of engine related work that we can’t accommodate. If you have a query or would like to discuss your engine related project please call Joe on 01902 338265 9am to 6pm, who will be happy to help.


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