VF31 with double ball bearing crank -advice

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VF31 with double ball bearing crank -advice

Postby ian.dabney » Sun Oct 21, 2018 8:28 am

I am refurbishing a black ariel with a VF31 engine, which I believe was built towards the end of 1930. The engine has a two ball bearing crank, rather than a bronze bush on the timing side. It also has rocker return strings. The crank cases are marked F and it runs a standard piston. Does the group know if some features of the model G where then adopted for next years VF31?
many thanks

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Re: VF31 with double ball bearing crank -advice

Postby Ian.Taylor » Sun Oct 21, 2018 4:03 pm

Hi Ian
My 31 VF ( Shipped in June 31 ) here in Canada had the helper springs on the rocker box as well. I removed them as I felt they were not really needed.My cam was a "F" type but replaced that with the 664 cam. Piston is NOS low compression.
I had the "G" Exhaust guide & Valve installed as recommended by our single spares supplier.

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Re: VF31 with double ball bearing crank -advice

Postby Roger Gwynn » Sun Oct 21, 2018 4:52 pm

The vertical ohv models are listed as having a 2 main ball bearings. They are also listed as having the rocker return springs 990-30 and 1000-30. The 'F' stamped on the crankcase mouth denotes a 'standard' engine as in 'F' as opposed to 'de luxe', stamped 'G' or later 'Red Hunter' stamped with 'H'. I have always assumed that this is because the bottom ends were built separately to the top ends and the builder of the top end and ultimately the builder of the bike needed to know which type of engine it was.
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