The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Chillipepper on 28.03. 2015 17:52

Title: Inner timing cover numbers
Post by: Chillipepper on 28.03. 2015 17:52
Hi All

Upon tearing down my 1952 plunger gold flash I discovered that previously the dynamo chain must have broke and pushed through to the area where the oil pump is -
Anywho I have been lookin for a replacement innner cover but Need abit of advice regarding the part numbers stamped into the cover
My original one is stamped with 67-286 - Ihave seen a few on fleabay but wit stamp marks 67-285
Question is will the latter fit ok or should I keep lookin for one that matches the original ???

Cheers

Chillipepper
Title: Re: Inner timing cover numbers
Post by: beezermacc on 28.03. 2015 18:10
They are all the same apart from the longstroke which is a different shape.
Title: Re: Inner timing cover numbers
Post by: Beezageezauk on 28.03. 2015 19:57
Hi Chillipepper,

Are you sure that the numbers quoted on eBay are the actual numbers shown on the inner casing?  The reason I ask is that the number shown on your casing is a "casting" number and for some obscure reason BSA used a part number that was one digit different to the casting number.  Therefore, those shown on eBay might be "part" numbers.

Beezageezauk.
Title: Re: Inner timing cover numbers
Post by: muskrat on 28.03. 2015 20:07
G'day Chillipepper. As beezermacc said all the same (bar long stroke) till you get to the super rockets with the tach drive. 67-0286 is a idler pinion shaft bush. 67-0285 is the inner primary cover.
A zero is added in front of the last tree digits to update the part numbers as above. Casting numbers are usually one number off the part number 67-0284.
Cheers
Beezermacc just beat me.
Title: Re: Inner timing cover numbers
Post by: terryg on 28.03. 2015 20:27
Re. the two numbers... My understanding is that one (lower, typically) part number is for the 'raw' casting and that the finish machined part must have a different number, usually but not necessarily +1. Using a single part number for both (different) parts would make stores operations and stock taking impossible with any real meaning.
Further, in my experience, two separate engineering drawings describe the casting and finish machined part.
Title: Re: Inner timing cover numbers
Post by: kiwipom on 28.03. 2015 21:10
hi guys, came across this info on  https://oldthumpers.wordpress.com   lots of information here,cheers
Title: Re: Inner timing cover numbers
Post by: Chillipepper on 18.04. 2015 12:16
HI all

Thanks for all the responses - replacement part now acquired following your advice

Cheers

Chillipepper