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discrepancy between parts drawings and Vincent Instruction sheets


Well Known and Active Forum Website User
VOC Member
In attempting to make up a list of crankcase bolt lengths from the Instruction Sheets , Series B,C,D and the Parts book drawing M.O 41, I encountered some problems.

The Instruction sheet # 11b at page six gives the crankcase bolt lengths and types. It refers to MO 41 from the parts book. MO 41 gives the positions of the bolts using part numbers, but not the lengths.

The Instruction Sheet lists position M as the drain plug, however on MO41, M is a stud up near the top of the crankcase. Also, MO 41 shows N as the drain plug while the instruction sheet ends at M.

In addition , the Instruction Sheets list position L as a 5 7/16 stud screwed into the driveside half. In MO41 is L a thru bolt.
Finally, the Instruction Sheet lists position I as an 8 3/8" bolt, however MO 41 does not have a position I, it jumps from position G to position H for some reason.

I now see yet another discrepancy. MO 41 shows a long bolt at K , probably the 8 3/8" length by scale, however the Instruction Sheets list it as a 6" bolt.

I'm not sure if any of the informaton in the Instruction Sheet description of the bolts is correct. Has anyone else encountered this problem between the Instruction Sheet 11B page 6 and MO41?

Last edited:


Well Known and Active Forum Website User
VOC Member

A few years ago now, because of the many inconsistencies/inaccuracies in the Instruction Sheets, the ever youthful and enthusiastic Frank Griffin, with help from Eddie Stevens and others, set about a complete re-write of said sheets in A4 size. The work was subsequently completed - with much additional information added too - and published by the VOC Publishing Company Ltd.

I suggest you avail yourself of a copy (Part No. RP/11 from the VOC Spares Co Ltd - its under £10) if only so that you can retain some of your hair...!

In short:
M is a 5-7/16 stud
N is a drain-plug
L is a 6" bolt.
K (and J) are 8-3/8 bolts. (All bolts are measured as overall lengths).

Drop me a PM if you need more info.

Peter B
Bristol, UK.
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