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

Only the centre ones should have been domed. The outer should be normal nuts. That said I have it the other way around deeper nuts in the middle and the nicer looking domed nuts on the outside. They should be 1/4 BSF from memory

Could you show the inside of these pistons ?

of course, tomorrow.

A couple of pictures from todays visit to my lockup, first up is the front wheel I picked up yesterday at Shepton jumble, as you can see the brake plate is nice, but the rim is shot, so I think I may well get a new rim fitted when I do the front end change.










Left and Right AMAL 930's, R41, and L42, soon to be heading for the ultrasonic bath.





The old pistons were/are Hepolite's





Back at the last Kempton Jumble, I picked up a nice set of Craven Comet panniers, and an old rack that may well end up being fitted to the Lightning.

I see that your carbs are 930/41 and 42
those mumbers was mounted on my A65L 1970 and I was curious what model those carbs was for?
the proper from the books are 930/34 and 35 which is now mounted

above is not a big issue just curious which model 41 and 42 are ment for from the beginning.
cheers
Morgan

I think you may be putting too much trust in the book, Morgan. There is no reason to believe that your carbs, and my carbs are not original fitment.

I had a quick glance and couldn't find reference to the 41 42 carbs. A search on the site didn't show anything up either. John Healy may know better but it's possible that when the extended tickler was released on new carbs that some carbs changed their designation number. It's only a guess though. The fact that you both record having these carb numbers shows that it's 99% possible they were original fitment.

Main thing is you have

#3 slide
2 ring needle with clip in the top slot
106 needle jet
Extended jet holder
180 main jet

Wouldn't do any hard to change all those parts for new and fit premier slides. Firstly though, check that the flange is flat.

I am going to ask AMAL/Burlen, they have extensive old records, they once told me about an old carb I had on a road rocket that wasn't "in the book" but was factory fitment.

All these old factory records and serial numbers are really only a reference guide, and should not be regarded as set in stone.
:bigt

I sent the head off to SRM this week for full refurbishment, and have also ordered one of their sump plates with magnetic drain plug.

I intend to fit an external oil filter to the bike, and have a choice of two, the standard "Norton" style with screw on filter, and a BSA B25 canister filter, but I can't find a suitable place to fit either? if you have fitted a filter to your A65, could you post a picture of where and how.

Those rocker cover nuts look like Norton Commando exhaust rocker cover nuts.

The new ones look correct for the inner or top pair.

You'll never see them with the tank on unless you really get down and peek..




Don in Nipomo

Hi Kev,


You're also aware of the Andy Gregory/Tri-Cor England filter, that uses the a triples' element? Fwiw, I've one of these on my T100, mounted pretty-much as in the picture, the T100 has plenty of space there.

Andy also offers an "oif" version; the inlet is in a different position, rather than there being any functional difference between "pre-OIF" and "OIF".

Hth.

Regards,

I just ordered and received this new SRM magnetic sump plate assembly for the BSA Lightning. The quality is outstanding as I hope you can see from the pictures.

I also sent my head off to SRM to have new valves, guides etc. It is right about now that I hope the bottom end is all ok! everything seems fine but I won’t know for sure until I fire the bike up. A scary thought.

It has been a wet day here in the UK, heavy rain on and off all day, so not too much done with the A65, but I did manage to hone out the bores on the barrels, and run the carbs through the ultrasonic tank. maybe if it is dry tomorrow I can get a bit more done.

Out with the old, in with the new...

Old pistons...





and in with the new pistons...





:bigt

Thanks Kev, but I thought about the insides of new pistons .
They are not relieved like JCC pistons around a gudgeon pin, so being in your shoes I'd check their weight comparing them to originals. I remember some Australian made pistons being much heavier than originals and I personally would avoid those.
Your gudgeon pin's circlips are not my favorite type as well.
Personally I prefer the type without any part of it hanging in the front of a pin, because in this case pin's end holds it in it's place. In the case of your circlips, pin can push it out of it's place hitting it during engine working.
Piston's rings are OK, but you can get Goetze made rings in GB now, which are also cast iron but have a spring for the oil ring and their quality is really high.
They will give you much better oil control than average cast iron rings.
Sorry for mostly negative post - just wanting to save you some pain with BSA in the long run.
Don't take my opinions for granted, I hope the rest of the guys involved with A 65 will comment.

Adam not negative at all, the pistons I removed were not the originals as they are +20, are they the same make as original equipment? As for the circlips, I actually prefer this type, these are the same as I use on the Moto Guzzi, and they seem to fit nice and tight.
I never got to weigh the pistons against the ones removed, but as I said it would make little difference as I wouldn't know if those were heavier or lighter than the standard ones.

Pulling it all apart, putting it all together.

I have now for the moment taken the motor as far apart as I intend to go for the time being. I have drained and flushed through the crank cases, and was pleased to find no metal in the drained oil after letting it stand in the tray for a week, and filtering it off over a strong magnet.

The cylinder head has gone off to SRM in Wales for full refurbishment, which includes lead free seats, new guides, valves, springs etc. This work wasn't cheap by any means, but it should last me out, and make for a good top end. I am looking forward to getting the head back so I can button up the top end.

Last weekend I cleaned off all the old base gasket material, and fitted the new pistons, I also honed out and painted the barrels ready to be fitted. I would have fitted the barrels but the supplied base gasket in the kit I bought was for the 1/2" stud version cases and not the 3/8" as required on the later cases, so again I find myself waiting.

Next I turned my attention to the front end and dropped out both fork legs, water had got in through the torn gaiters, and was evident in both legs, water came out of the right hand side, but the left hand stanchion is at the moment seized solid. So I have left it soaking in some penetrating oil for the week, I shall see how it does this weekend.

:bigt

Hi Kev,


Risking putting my foot in it, I thought 'earlier' cases had 1/4"-dia. barrel base studs?

Regards,

I was of course wrong with the stud size, but I was tired when posting

The inside of the new pistons? ok then as you asked...



I called round to see my old friend Terry the Vincent today, just for a cup of tea and a chat, always a good way to lose an hour, and whilst there Terry gifted me an original genuine pair of of AMAL alloy levers, you see lots of new and a few original Doherty versions, but the Doherty's are thicker and straighter in the lever, where the much rarer AMAL version have a slimmer profile, and are flatter where your fingers rest.
These are in great condition with the original stamped clamps, although one lever end has a little road rash.





:bigt

Really envy your ability with the camera Kev.
I'm terrible in this regard.
Anyway difficult to say what these pistons are, I hope not JP - people had problems with them.
I'm just baffled they don't have relief around piston pins.

I am going to sell the whole lower fork assembly including front wheel brake etc, the forks are removed and stripped down and will require new stanchions etc before use, one slider will also need a little work as it has a tight spot which had seized the forks up? the front wheel is in fantastic condition though.

The lightning seems to have taken up residence on the bench right now, the whole front end is out, the head is away at SRM having a full on valve job, I was hoping the head may have been completed this weekend but not so. As can happen sometimes, I managed to break a piston ring fitting the barrel, and the broken piece of course dropped into the crank cases, and could not be seen. But some fishing around with a telescopic magnet found it in the bottom of the cases. So after again fitting a spare ring to the piston, and some help from Paul, I managed to get the refinished barrels in place, bolted down.



Next it was time to fit my new SRM magnetic sump kit, after removing the old studs I offered up the new gauze filter, only to find that it did not fit! it seems that SRM sent me out a kit for a B50 or other single, as the hole in the gauze was too small (8.5mm instead of 11.5mm) to go over the scavenger pipe. Luckily my old filter gauze was in very good condition, so I decided to use that rather than wait for a replacement from SRM.

Then it was just a case of bolting it all up to the underside of the motor.





:bigt

Hi
I'm a newbie to this forum so hope it's ok muscling in on this thread which I've read with interest. I've also bought an unregistered lightning USA which is virtually identical to Kev's. It has matching numbers a65la10997 y. I'd like to know what year it is. The us title says 1970 but there isn't a date on the frame tag sticker only the stamped numbers(untapped) the vintage mcc dating gurus say It left the factory 5 Jan 1967 which concurs with bsa oc info posted online which says A65 LA relates to 1967. However, various clues on the bike indicate its later than 67 : 2 screws on metal tank badge; twin leading front brake; bsa 'watermark' on engine numbers tag. Bantam John (bsa parts specialist in uk) tells me the bike probably had a replacement bsa engine at some point with bsa dealer restamped engine number to match the frame.

Contributors to this thread suggest la65 -y relate to 1970 - apart from looking at parts on the bike itself which could have been changed over the years, I'd be interested to know whether mine is 67 or 70. Could someone explain please why la -y does not relate to 67 as indicated by bsa docs within uk?

Cheers

Ian