Offset Crankshafts for BSA twins (500, 650 and 750cc)

All BSA crankshafts are machined, welded, ground, balanced and nitride heat treated for extra strength and wear resistance. Crankshaft Customers must supply weight of one piston with rings, wrist pin, cir-clips and identify the connecting rods they plan to use (stock or other). The customer is responsible for making each piston weigh the same amount. Bearing shells are supplied with each crankshaft we ship. The drive side journal is offset behind the timing side journal, in the direction of crank rotation, to match camshafts sold by SRM at Ed G Cranks can also supply a reground, nitrided BSA A7/A10 or A50/A65 camshaft. A limited number of profiles available; we can recommend other cam suppliers that have more profiles available as noted on the Camshafts page on this web site.

The BSA timing side journal can be ground to stock size or modified to suit a roller bearing timing-side conversion done by firms such as (SRM Engineering or British Cycle Supply at If not building a racing or larger displacement BSA engine we recommend using stock timing side bushing and a high-pressure oil pump. Later style 1.500" timing side bushing is recommended for A10 engines to replace original 1.375" bushing used on earlier (pre-1958) crankshafts. An oil filter must be used with an offset crankshaft as stock sludge trap is removed. All cranks are lighter then stock so they have less inertial weight for faster acceleration. A65 and A10 crankshafts are balanced to 50% unless another balance factor is specified by customer. The higher the RPM range where a desired smoothness is required the lower the balance factor number. A racing engine may use a balance factor of 40% for best smoothness above 6000 rpm but it will vibrate a lot below 3000 rpm.

All 76 degree cranks cost $300 USD more then quoted prices shown below

74mm (STD) Offset Crankshaft

Modified timing journal Offset Crankshaft

A10 and 84mm stroke A65 Offset Crankshaft

$1150 USD

$1250 USD

$1400 USD

Shipping within North America $85 USD or less. Overseas prices about $250 USD

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Flywheel Options


Balanced A65 Crankshaft


Unbalanced A10 Crankshaft


A reground A10/A7 or A65 Camshaft is $400.00 using our recommended performance profile. Ed G. Cranks supplies a donor camshaft for all A65/A50 or A10/A7 engines. Contact us if you require a special profile or need information about other camshaft suppliers.

Standard Offset Crankshafts

Standard Crankshaft Repair

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