Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 1970 Lightning "Y" Bike Project...

The BSA owners club is UK focused and does not worry about what happened in the US despite the majority of BSA's output going to the US.

There is a really long thread on this board which explains more but can't find it. In short if it has a -Y but a 67 number but has 70 parts its a 70. There may have been a 1000 67 A65's that were made and had to be re-exported but there is more to the story than the BSAOC has on their website.

Just to confuse matters more there are 70 bikes stamped with a Y not -Y but that is a reference to extended warranty.

Hi Ian,

Firstly, welcome to the Forum.


Note there is a significant difference between "-Y" (Dash Y) and just "Y". The thread "kommando" couldn't find is http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=403236#Post403236, be prepared to be there a lo-on-ng time ... and note there will be short test afterwards.


Are the engine numbers and "bsa 'watermark'" stamped into a 'pad' raised above the surrounding crankcase metal? Are the nuts holding down the barrel base to the crankcase 12-point rather than normal 6-point, does a 1/2"AF 12-point ring spanner fit (ignoring that the barrel material might be a bit close for just any spanner to fit completely), are the studs into the crankcase 3/8" o.d. and threaded UNF? If so, more clues it's more-likely '70 rather than '67.


As the saying goes, "Denial ain't only a river in Africa" ...

Hth.

Regards,

Thanks for your replies guys.

OMG! I didn't realise all the discussion about LA Y bikes! How complicated. The answer to all your Q's, Stuart, are 'yes' therefore it looks as if my bike is a 1970 bike after all which concurs with the US title. I have actually applied to BSAOC dating officer for a dating letter so I will wait with interest. Hopefully thereafter I can start the uk registration process.

Thanks for your help guys. This looks like a great forum! I'm going to post a separate message about gearbox cluster removal...

We need pictures, just so you know.

and welcome

So another Y bike, we will soon have enough for our own sub section :bigt

Ian, if you take the seat off and look at the bolt mounting brackets, this will tell us a lot, 69/70 frames had different seat brackets to 67/68 and pre 67 had them different again.

Some 69/70 frames had fairing tubes welded to the headstock, this wasn't on earlier frames and all 69/70 frames were fitted with a swing arm which had bronze bushings and not rubber silent block bushes, the swing arm bolt was also solid where as the earlier ones were hollow.

As already mentioned, all 70 engines had a bsa embossed number block, as did most 69's but the very early 69's were on a raised block, but not machined flush or bsa stamped.

Here are a couple of shots of the frame. The front of the seat doesn't latch onto a part of the frame - I wonder if this has broken off?

Do these photos help identify the year?

Thanks guys

3/8ths bihex barrel studs/nuts make it 1970.it will have a vertical clutch cable entry as well. The seat should have a pair of forks/ bracket at the front to engage with the horizontal bar at the rear end of the frame top tube.

Top end should all be back together this weekend if I don't go to a Guzzi camp in Gloucester....

I can see the remnants of the front seat bracket in the picture. It either broke off or someone cut it off.
I've had several A65 with the Y and from all my research they are '69, '70 specification even though the serial number suggests it's a '67.

If you plan to put it together this coming weekend Kev, don't forget to anneal the gasket even when new, and cover it with copper cote both sides.
I hope the bottom of your head will be machined by SRM.
After you start riding, proper retorque is essential to keep your cylinders sealed.

My head having returned from SRM, was now ready to be fitted, and after a question asked in the competition section, I equipped myself with some copper sealant, and a pair of small o-rings, so I was ready to go.

Barrel and gasket prepared and ready for the head to be fitted..



Head looking good too..







:bigt

How do you guys torque the outer four head nuts, I can't fit a socket/torque wrench on these four, so have done them by "feel" using a spanner.

You can buy a "crowfoot" open-end wrench that has a 3/8" or 1/2" drive hole on it, mount it at 90 degrees to the shaft of the torque wrench so that the overall length is correct, and torque it that way.

I don't bother, though ... "feel" has always worked well for me. Have never had a head leak.

Lannis

Get a 1/2" af ring spanner, weld a 1/2" drive adaptor to it use the wrench on this with the spanner at 90 degrees to the torque wrench.

Looking good!

Now where was I?

With the head all bolted down, and the rockers installed, it was time for some new SRM adjusters to be fitted...







Next on the list was refitting the exhaust system...








Now I have a couple of questions....

1. can someone tell me the thread size of the rocker cover head studs, the end that goes into the head. As I need to run a tap down the threads in the head.

2. I am after the part number for the oil tank drain/filter gasket.

Thanks.

Centre studs are 1/4 BSF tapped in the ally.

The pictures are well lit and in focus too, yay!

And the pipes are stock/original?

What is the latest opinions about the mushroom tappet adjusters?

Looking good kev!

I'd use phenolic distance pieces between head and the carbs.
In town and in the traffic jam they can save your carbs from overheating.

My little BSA has had to take a back seat for a while, I just can't find the correct forks for the bike, so it is just sitting on the bench until something turns up.

Hi Kev,


Risking asking a silly question, you do know that '70 BSA forks are essentially the same as contemporary Triumph forks? The only really BSA-peculiar bits are the sliders; fit Triumph sliders - and ride the bike :bigt - 'til the Beeza bits come along?

Hth.

Regards,

Or leave the triumph sliders on and don't change them because they don't looks any different

Hi Allan,


I did wonder ... I couldn't see any difference but, as most other '69/'70 forks part numbers are the same as Triumphs, I thought Small Heath must've given the sliders different part numbers for a reason I couldn't see ...?

Regards,

They could have their differences but as the wheel fits the same they look close enough for me not to be too worried if it was mine.

I can't find Triumph ones either, I ave been looking. I have the correct wheel now with 8" twin leading brake. One will turn up.