F: Frame Part # 327

[Cyborg]

The bolt 327 that keeps the FT95 damper drum from rotating is listed on the VOC Spares site as 1/4” BSF. The holes in the damper drums that I have are just over 3/16, as are the corresponding holes in my B RFM. Coventry Spares also lists 327 as 1/4 BSF.
Anyone know what the correct part numbers are for the 3/16 bolt and nut?

 

[chankly bore]

No mate it was a 2 B.A. bolt, part no. 617 on the earlier bikes. I've been told the inner arm of the bracket was threaded to take it, as the length of the bolt was 1". It was replaced by the 327 bolt and nut, probably 91, or maybe 731 by reason of greater fortitude. You'll see many of the damper drums on original machines with both sizes of hole, usually diametrically opposite.

 

[Shane998]

The bolt 327 that keeps the FT95 damper drum from rotating is listed on the VOC Spares site as 1/4” BSF. The holes in the damper drums that I have are just over 3/16, as are the corresponding holes in my B RFM. Coventry Spares also lists 327 as 1/4 BSF.
Anyone know what the correct part numbers are for the 3/16 bolt and nut?

View attachment 51044

Inner ear threaded but I have another straight lug RFM that is larger non threaded hole probably a modification

 

[Cyborg]

No mate it was a 2 B.A. bolt, part no. 617 on the earlier bikes. I've been told the inner arm of the bracket was threaded to take it, as the length of the bolt was 1". It was replaced by the 327 bolt and nut, probably 91, or maybe 731 by reason of greater fortitude. You'll see many of the damper drums on original machines with both sizes of hole, usually diametrically opposite.

Does anyone know what year the change occurred?

 

[chankly bore]

From what I've seen, the curved seat lugs all have the 327 bolt, K.T.B. says "2 B.A. on very early machines." My series "B" Parts List, which shows the 2 B.A. bolt is from around August 1947 according to the drawings which are dated, most are not.

 

[Simon Dinsdale]

Does anyone know what year the change occurred?

Mid 1949 when the RFM was redesign.
Note the change had nothing to do with series B or C as the change occurred across the range.

 

[Robert Watson]

/1997 from June 49 has 2 BA

 

[Keith Martin]

/2146 from May of 49 has the 327 1/4" bolts.

 

[Cyborg]

I was awake at 3 AM, (not because I was fretting about the fasteners) and was wondering if it might have been related to the switch to curved stays.
On another forum, there was a mention of the second 1/4” hole being common and perhaps intended for oiling the damper? That seems odd to me, but then again Vincents seem odd.

This is a photo of MM’s 50 Shadow. Do all the later damper drums have two 1/4” holes?

 

[LoneStar]

Not the two on my Shadow, nor the two extras that came with my Rapide basket case. In fact, I can't recall ever seeing one with two holes - although it's not something easy to notice.