McCulloch BP-1 ................................Updated Jan 25th 2011

Thanks to the generosity of American Peter Suomala of Alabama i now have a McCulloch BP-1 in Australia.
Peter gave me his spare BP-1 this morning and the saw is now complete it will add another page of McCulloch's early history into my collection.

These Chainsaw's have a fascinating history being produced in 1962-63 whereas some 33,000 were produced then recalled because of a fear that the saw would over-rev and cause injury to the operator but this failed to happen and most of the bulk of the saws were destroyed.

No doubt some escaped the recycler and found their way into various collections worldwide now my collection will have one in pride of place.

Thanks Peter your generosity is truely appreciated ................................. Mc Bob.

Model: BP-1

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MANUFACTURED BY: McCULLOCH MOTORS CORP.
LOS ANGELES, CALIFORNIA, U.S.A.
SERIES OR ASSEMBLY NUMBER: none
YEAR INTRODUCED: 1962
YEAR DISCONTINUED: 1963
ENGINE DISPLACEMENT: 2.7 cu. in. (44cc)
NUMBER OF CYLINDERS: 1
CYLINDER BORE: 1.75 in. (44.4mm)
PISTON STROKE: 1.125 in. (28.5mm)
CYLINDER TYPE: Aluminum with cast iron sleeve
INTAKE METHOD: Balance piston acts as intake valve
MANUFACTURER ADVERTISED H.P.: 4.2 @ 10,000 RPM
WEIGHT : 15 Lbs. (powerhead only)
OPERATOR CONFIGURATION: One Man operation
HANDLEBAR SYSTEM: Rigid
CHAIN BRAKE: none
CLUTCH: Centrifugal
DRIVE TYPE: Bevel Gear reduction 2.0:1 or 2.9:1 ratios
CONSTRUCTION: Die cast magnesium
MAGNETO TYPE: McCulloch
CARBURETOR: McCulloch
MAJOR REPAIR KIT: n/a
MINOR REPAIR KIT: n/a
AIR FILTER SYSTEM: Flocked wire screen
STARTER TYPE: McCulloch automatic rewind
OIL PUMP: Automatic
OPERATING RPM: Goverened at 12,000
IGNITION TIMING: fixed at 27 degrees before TDC
BREAKER POINT SETTING: 0.018 in. (0.45mm)
FLYWHEEL/COIL AIR GAP: 0.008 to 0.010 in. (0.2 to 0.25 mm)
SPARK PLUG TYPE: AC C45W
SPARK PLUG GAP: 0.025 in. (0.63mm)
CRANKSHAFT MAIN BEARINGS: Ball
FUEL TANK CAPACITY:
FUEL OIL RATIO: 20:1
RECOMMENDED FUEL OCTANE: Regular
MIX OIL SPECIFICATION: McCulloch two-stroke chain saw mix oil
CHAIN PITCH: 9/16 in.
CHAIN TYPE: McCulloch Auto-Mac with built in sharpener
BAR MOUNT PATTERN:
SHORTEST GUIDE BAR SUPPLIED: 16 in. (40cm)
LONGEST GUIDE BAR SUPPLIED: 24 in. (61cm)
COLOUR SCHEME: McCulloch Yellow with Black
PAINT CODES:
ILLUSTRATED PARTS LIST:
SERVICE MANUAL:

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COMMENTS:
Worlds only Balanced Piston engine chain saw. The BP-1 is a high speed engine utilizing one piston for power and one for balance and as a sliding intake valve.

This saw was sold for a very short period of time and then withdrawn from the market by McCulloch.

Because of the RPM that the engine was capable of if the governor failed it was feared that it would disintegrate and injure the operator.

Bob,

Thanks for the kind words. I’m glad you are pleased. Two quick notes about the BP-1, the first from my father: he said the dealer he got the saw from said that one of the reasons that McCulloch took the saws off the market was because of the saw’s complexity and that few mechanics could fix them without messing them up – he said that mechanics of the day were “stripping threads and breaking things left and right” so warranty cost might have been another reason. The BP-1’s contemporaries weren’t very sophisticated and downright ugly when compared to the sleek styling of the BP-1. This is the second point: from an esthetic point the BP-1 is without equal in my opinion. I once showed it to a friend of mine that knew saws (but not the BP-1) and he was shocked when I told him it was built in 1963. The BP-1 is a rare example of a highly sophisticated mechanical design for it’s day as well as a premier example of industrial design. At least in my opinion!!!!!

Here’s hoping McBob’s BP-1 lives to runs again!

Peter

Let me tell you the story about why I’m giving you the saw.
Last December I bought an old but lightly used Powermatic wood planer that was built in the USA that they stopped building in 1995. It is large and heavy weighing 1,300 lbs. but nothing made today can equal it. It was missing the dust hood and I wanted an original one so I started looking and found a dealer that had one but he wanted $175 for it which is robbery.

I posted on a forum and asked if anyone had a used one for sale. A guy emailed me and said he had one that had never been used if I wanted it. I emailed him back and asked “how much?”. He replied: “it’s yours – what is your address – send me a check for shipping costs that’s all”.

I am still struck by this man’s generosity and each time I use the planer I always think about a guy that I don’t even know.

Anyway have a great time with your BP-1 when you get it and be sure to be generous to a total stranger when you get a chance. It’s worth it believe me!

Peter

Bob,

One of the bulletins you have dated April 24, 1963 states that the “new” version fuel tank will fit all BP-1s built to date however the tank must be fitted to any saws after #6,975. This says to me that less than 7,000 were built from start of production until April 1963. With only 8 months left in 1963 – not knowing exactly when production started and stopped – I would say that it is very unlikely that there were 30,000+ built - I’d say that there were less than 10,000. What do you think?

Please send any more pieces to the puzzle you find! I’m keen to see the actual bulletin or dealer letter announcing the BP-1 recall – that will be a critical piece – keep looking!

Peter