The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: rocker21 on 26.11. 2025 09:50

Title: new A7 crank
Post by: rocker21 on 26.11. 2025 09:50
the Canadian company called british cycle supply company have some brand new old stock crankshafts for sale at  450 Canadian dollars will probably need a cleanup as they are 70 years old.
Title: Re: new A7 crank
Post by: Radlan2 on 26.11. 2025 13:19
              A friend of mine who has spent his whole working life as a motorcycle mechanic dabbles in buying and selling on. A couple of years ago he bought what turned out to e a very sweet running A7 at auction.
     He was told by the previous owner that a new crank had been purchased from the states, the very interesting thing to me is he was told the crank was large journal.
             I have not seen conclusive proof that such a crank was sold by the factory but it should have been because I have seen a part No's for LJ A7 rods advertised in the states. Could these cranks be something special?
     Unfortunately my friend moved his bike on before we could verify anything.
Title: Re: new A7 crank
Post by: JulianS on 26.11. 2025 14:07
They were for the Daytona models I think.
Title: Re: new A7 crank
Post by: JulianS on 26.11. 2025 18:58
See below 1957 bulletin from Hap Alzina in California and the comments about Al Gunter's works 1954 Daytona A7 being fitted with twin carbs, a heavy base cylinder and heavy duty crankshaft. All for $425!
Title: Re: new A7 crank
Post by: rocker21 on 27.11. 2025 09:49
90 Canadian dollars to send to the uk, bound to have customs fees on import, looking to see how many they have and if a deal can be done.
Title: Re: new A7 crank
Post by: Joolstacho on 27.11. 2025 23:07
Would love to get my hands on one of Hap's Shootin' Stars.
Title: Re: new A7 crank
Post by: Radlan2 on 28.11. 2025 07:56
Hi Rocker
       I have got a VGC STD though used crank I had intended to use in one of my Daytona reps but would buy one of these in an instant if they are LJ type, let me know?
Hi Julian
       Never seen this before, you have a mine of great info there keep it coming.
      Best Regs
           Chris   (Dorset)
Title: Re: new A7 crank
Post by: Beeza on 28.11. 2025 09:15
I’ve tried to find any information on the elusive LJ A7 crankshaft, to date no one has provided proof of such beast, my other thoughts regarding the LJ A7 crankshaft are that there has never been mention of the matching LJ A7 conrods, until now, is it possible to get the listing details for those con rods please, although you can easily use A65 con rods if the elusive LJ A7 crankshaft was on your bench.
Title: Re: new A7 crank
Post by: rocker21 on 28.11. 2025 10:30
i have bought 1 of the cranks, from the pics it looks pretty good, they have 1 more left. will be selling a crank that i was going to use to make another motor and using this one instead.
Title: Re: new A7 crank
Post by: Radlan2 on 28.11. 2025 14:01
           The Daytona con rods are listed in the "speed equipment" parts list which Julian has posted on here from time to time. Pt No:- 67-1207, what I have found elusive is details about the pistons used in these special engines.
           As mentioned before I have successfully converted an A65 crank to fit pre unit cases but it does take quite a bit of engineering.
            Rocker. have you part No, journal size or other details about the crank you have bought?
           Chris
 
Title: Re: new A7 crank
Post by: JulianS on 28.11. 2025 20:48
There are 5 factory brake test results for 1954  factory prepared Daytona racer engines CA7D 101 - 105 in the members area of the BSAOC web site.
These give cam type (the 358) compression ratio, head gasket thickness (which varied engine to engine) carb settings, valve clearances plus torque and bhp readings.
Title: Re: new A7 crank
Post by: Beeza on 28.11. 2025 21:46
CA7D-101 sounds familiar LOL
Title: Re: new A7 crank
Post by: rocker21 on 15.12. 2025 11:11
new crank has just arrived, still got all the old tape on the bearing surfaces, now need to find a flywheel and get it balanced. it looks good just needs a bit of a cleanup.
Title: Re: new A7 crank
Post by: A7JAY on 15.12. 2025 11:54
new crank has just arrived, still got all the old tape on the bearing surfaces, now need to find a flywheel and get it balanced. it looks good just needs a bit of a cleanup.
so you might have the one you was going to use for sale?