Author Topic: Difference between early and later timed breather  (Read 724 times)

Online bikerjohndavies

  • John Davies, Bath, UK
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I was wondering if somebody could tell me the difference between the early timed breather part number 67-130 and the later one 67-987?
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1958 BSA C15, 1961 Triumph T120R

Online bikerjohndavies

  • John Davies, Bath, UK
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Re: Difference between early and later timed breather
« Reply #1 on: 23.07. 2015 08:07 »
Somebody must know what the difference is between the 2 different part numbers, if any.
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1958 BSA C15, 1961 Triumph T120R

Online bsa-bill

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Re: Difference between early and later timed breather
« Reply #2 on: 23.07. 2015 08:17 »
think I read some where the peg is not in the same place  (relative to the keyway) but I've no personal knowledge
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online bikerjohndavies

  • John Davies, Bath, UK
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Re: Difference between early and later timed breather
« Reply #3 on: 23.07. 2015 08:30 »
Thanks Bill, Yes the peg on the early long stroke cam pinion is at the 12 o'clock position compared to the keyway while on the later short stroke motors its at 1 o'clock. That made me think that the timed breather must also be different otherwise the breather hole would be open at a different part of the stroke. Cheers, John
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1958 BSA C15, 1961 Triumph T120R

Online duTch

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Re: Difference between early and later timed breather
« Reply #4 on: 23.07. 2015 08:57 »

 All I know is I think my Plunger one is a different shape/profile on the top/outer end of what I remember my R.Rocket had... *dunno2*..... other than that  *dunno*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
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Offline trevinoz

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Re: Difference between early and later timed breather
« Reply #5 on: 25.07. 2015 02:20 »
BikerJohn,
                        The difference in the breathers is the early 67-130 is waisted on the outer end and the 67-987 is tapered.
67-130 was fitted to both long stroke and short stroke engines.
I think that the change of form was for 1953 when quite a few mods were made.
I can't see why they couldn't be interchanged with each other if the correct one for the year wasn't available.
The holes appear to be in the same position on both types.

Online bikerjohndavies

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Re: Difference between early and later timed breather
« Reply #6 on: 25.07. 2015 07:55 »
Hi trevinoz, thanks for the reply. That explains it but as you say the holes are in the same place on both versions whilst the long stroke cam pinion has the peg at 12 o'clock while the short stroke is a 1 o'clock so the breathing timing on the long stroke must be slightly different. That is unless the keyway on the cam shaft is in a different position. The joys of classic bikes.
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1958 BSA C15, 1961 Triumph T120R