Did any BSA's get the frame upgrade which is generally reported as being effected in 1972? I have yet to see one with a lower seat height. Can anyone enlighten me? Phil
My 1972 OIF 650 is quite low, I did wonder myself. When it's on the centre stand the front wheel is over 3" off of the ground.
This bulletin ammended the 1972 A65 parts book, including a change of frame. I presume the new part number is the lower frame.
I didn't know there was an actual change of frame, I thought it was just thought it was shorter suspension units at the back. Learn something every day!
Odd that it was criticized as being too tall at the time, yet I'm 5'4" and manage OK, but struggle with a lot of modern bikes.
Tell me about it! Why does the MYTH that these bikes are tall still do the rounds after 40 odd years? In a recent article in Classic Bike Guide the author just had to mention the seat height was tall. He didn't qualify that with 'compared to other bikes before it' or similar.
I looked at the specs of a mediocre 1998 Suzuki 600 Bandit recently and the seat height was described as 'medium'. The OIF Thunderbolt was 31" the Bandit was 32.5" yet I've never heard anyone complain about the height of a Bandit.
Where is the frame part number please. This would explain why they also made a centre stand 1" shorter or longer ? Thanks
Thanks for the replies.
There may well have been TWO part numbers for a revised frame. If I could find the equivalent of a second version of the update schedule above, one tabled earlier, maybe that would answer the question. Why say this? Well there was a BSA Lightning sold here a couple of weeks ago on ebay that had an Ivory frame which was reputably a replacement frame for a typically faulty first run of the grey frame. The bike came here by way of America. The frame number was not in the same format as the regularly listed ones.
If only we could find the head of the BSA "Frame Department" for a recollection or two!!
If I could find the thing, somewhere in my piles of paper is a book with the manufacturing specs of the UH bikes. It was the copy of one of the engineers working there, and from memory it did have some of those blue headed update sheets, plus memos about "stuff" from other people in the tech side. I just need a week to sort the stuff out.
I've got both 1971 and 1972 versions of the OIF frame and the only difference I can find is the narrower seat hinge positions on the 1972 frame. The seat height on both is exactly the same with no modifications to the top seat frame rails. To my knowledge BSA didn't have time to respond to the almost hysterical vitriolic criticism by the popular motorcycle press of the day. I wonder what these obviously vertically challenged test riders would make of today's offerings??
The only other frame modification I'm aware of, is the rear engine mount where it attaches to the vertical oil tank tube. My 1972 frame doesn't have this, although I have seen machines with it, as illustrated in the 1972 parts catalogue. Maybe the only time a part number is changed is when it affects another part??
I don't believe any modifications were made to the frame to address the difficulties with putting the machine on it's main stand. Main stands from a OIF single will solve this problem, being identical to the twin apart from being 3/4" sorter from the foot to the stand pivot. On my 1972 machine I've used a stand from a very late Triumph T140 (PN 83 7532). This is the same height as an OIF single but has a different arrangement for the pivot bolts, but fits extremely well with no modifications necessary to the frame.
I've got 1971 produced sold in '72 OIF model (black and red originally as best I can judge) and I would say the frame is low. I can certainly get both feet flat on the floor from the saddle.
Looking at the brochures for 1971 and 1972 the seat heights are, respectively shown as 32 and 31 inches. The seats are shown as different part numbers. Maybe new seat itself was lower by change in its design or mounting?
Later seats not only had the forward hinge position altered they had thinner foam fitted to give a lower seat height. The frame modification which later Triumphs had, lowered the two seat rails where they attach to the oil tank near the filler. BSAs were always near to the base of the filler as in your 1st photo, whereas later Triumphs were a good 1" lower.
Staying on this subject, could someone please measure the centre to centre fixings of the rear shock absorbers whilst on the side stand. mine with new shocks is 11 1/2".
Hi Colin
Are you sure you don't mean 12 1/2"? the Hagons that I've got fitted to my 71 Firebird are a full 13", which according to Hagon are correct. I'm trying 320mm (12.6") shocks on my next OIF project.
Cheers Jim
Good stuff! Although the info is not conclusive, it seems possible the BSA did not survive long enough to get the lower frame in production.
Thank you to those who have contributed, and keep those cards and letters coming!
Servodyne. This explains a lot with the height of my 1972. The shocks centre to centre are 11 1/2". They were new this year ? I am not delving tonight, is it likely I have them on the lowest
setting. Thanks.
Shocks adjusted to full height, now have a taller bike. Thanks.