The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Ron B on 28.01. 2012 21:41
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A general question- What year or serial number did the A 10 engine get a thick flange barrel? And what year or serial number did the A10 get a 356 cam? And lastly, when did the three bolt crank enter the picture. Somebody must know this bit of trivia.
Thanks Ron B.
Fridley, MN USA
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The 356 cam was introduced at the beginning of the A10 in 1951 for the sports models A7ST and Super Flash and the A7SS when introduced in 54. The 334 cam, used on basic models, was dropped at the end of 58 and the 356 was then used on all models whilst the 357 was adopted for the sports models in 61. Thick flange barrels (67-1210) were used by all 650 models from 1958 and by the Sports models from 54. The use of three-bolt crank matched the thick flange cylinder application.
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Thank you for the info. I have a plain new no number crankcase with a 356 cam and three bolt crank plus thick flange barrel. I did not know what year this thing represents, now I have an idea if what I have. Thanks again Ron Bohm
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The crankcases should have a year date stamping on the outside/front/bottom/nearside. Have a look at this expired ebay item http://www.ebay.co.uk/itm/290649718237?ru=http%3A%2F%2Fwww.ebay.co.uk%3A80%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dp5039.m570.l1313%26_nkw%3D290649718237%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1 (http://www.ebay.co.uk/itm/290649718237?ru=http%3A%2F%2Fwww.ebay.co.uk%3A80%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dp5039.m570.l1313%26_nkw%3D290649718237%26_sacat%3DSee-All-Categories%26_fvi%3D1&_rdc=1)
scroll down to bottom of listing for pic of date stamping.