For a long time I have thought about to buy an old timer MC. I am a member of a Motor Cycle Historical Club, MCHK. I find this club to be a good one. I have been a member since 2003 and owns a MC from the same year. This one didn't feel so good and I felt that an old timer would suit the membership much better. I must be one in the gang. It takes of course tenths of years to get rid of the stamp new beginner. All others with Triumph, AJS, Matchless, Norton and other marks, who had been in the game since the 50th will make an eye looking down on me. Till this time is over I will use the possibilities of the club and be a good boy way down. After I had bought my Sarolea 2005,  my working on this MC was decreasing and the feeling for something old between coming up. I have a mc from the 50th, I have been driving a Suzuki 2003 and a 83 Kawasaki. Why not own a cycle one from the 70th. An English and middle prized. Easy to get spares i Sweden and the last try from the English MC industry. It should be a twin. I started to look in ads and came to understand that BSA was the most common model. The last of them were sold in the beginning of the 70th. BAS-motor is a firm in Sweden selling parts to English cycles like BSA, Norton and so on. Used Ariel and AJS are hard to find ads on. Now it happened that I had 2 ads for BSA. The same year and model. One from 53000 SKr and one for 43000 SKr as first prize. It was in Stockholm and the other in Umeå northern of Sweden. Both seemed to be in good order. It is always a gambling. Those who say that the object is renovated up and down might have been tired and just screwed it together. Only the outside is nice. It is always a risk. Of course I choose the cheaper cycle. It is easier to bargain the lower price.
To go to Umeå is an adventure. I wont go there twice. I packed my MC-clothes, investigated all possibilities  to travel there. The cheapest was to go by bus directly from Stockholm to Umeå. 370 SKr plus my travel to Stockholm 220 SKr. I had a room booked at Hotel Dragonen Umeå for 600 SKr. Then the idea was that I should drive the cycle back to Virsbo, 700 km, where I live. Imagine what you can make if you really want. I took the buss and during the 9 hours tour Stockholm - Umeå was to meditate upon things how this bus company could get their finance to give money for wages. Study my traveling companions and their behavior. This was interesting. Many of them made up a invisible border around them. Just as they had closed themselves inside a room. They inserted immediately their mp3-player in their ears and closed the eyes. This will last only for some hours, I thought. I was right because the players disappeared and it was time for sleeping. Then bread and butter was taken out and the book with very small text height. This is an impressing thing on others in the bus. No one could see what they were reading. After 5 to 6 hours they don't manage to play their closed theater. The energy is over. It is funny because there are only girls, in the close company of the bus, who perform this way, just as they have activated an isolating electrical power field around themselves. Last hour there was a terrible mobile calling "I am soon in place" and so on. At arrival 21.45 everybody run away and I found myself alone outside the bus.
This about the adventure going by bus in Sweden.
NB: I read one book myself with big text height by Staffan Heimersson. One chapter an hour.

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BSA Lightning 650 1970 Driving back to Virsbo 1

Who thinks it is nice to have an eye catching cycle, because you get always easy contact with people, who think it is a nice cycle. Good when you don't get the engine to start. There are always people ready to help with a push. After filling up I rolled out on the main road E4 southwards. I passed Umeå and studied the impressing buildings for the Botnia railway. This I am sure will help northern part of Sweden to an economical raise. It may take 10 years. I continued with a speed of 90 km/h. Well I didn't know because the speedometer and rev. stopped at 3000 revs and 75 km/h. and had big difficulties to go higher although I understood that the values must be higher. Second filling up was Örnsköldsvik only 111 km from my first. My body needed something to drink and OK-Q8 petrol station is a good stopping place just down the ski jumping building where the jumpers are skiing under a railway bridge to stop. They are jumping over the town. In this ski jumping place Jan Boklöv developed the V-style. The only used way of ski jumping today. He got a Swedeish national price "Jerring Price" 1989 after winning the World Cup of Ski Jumping, year before.
Here I filled 6 litres petrol one CocaCola and 2 Hot Dogs. Then I didn't manage to start my BSA. It was hot  and perhaps I gave him to much petrol. The engine was still a little warm. In such a case it is easy to choke to much. For me BSA is a "he".  My strength to kick went quickly to an end and my try to run with it was doomed to fail and took my last energy. When I was hanging and deeply breathing over the steering, thinking over my situation, 2 guys were driving up to, me in a Van, asked if I had problem. "Would you like to have a push"? Sure of course. On the second try, with a resting pause between he started. I waved thankful "By, By", because I didn't dare to stop. I rolled out into the traffic roundabout and continued the E4 towards the High Coast and the new bridge north of Härnösand. Unnecessary stop to view the sight was not done and the first stop was in Sundsvall in front of stop lights and a big lorry behind. Here the engine stopped when light switched. I was standing in middle lane and could not see if cars were coming on the right side. The long distance lorry was eager to start. Now I had to be calm. I had to move out of his way. But should I dare to kick myself to the inner lane when I couldn't see backwards in the inner lane which for the moment was empty. No choice. The lorry honked at me and I rolled slowly to the side. A car sweeps ahead to the right of me and after I came to the side. Here I got my engine to start at once and could slide away before traffic light changed. My engine chattered a little and I wondered if I had reach the petrol reserve. I switched on the reserve tank and after a while the engine was good running again. Now I had to find a petrol station although I knew that I could drive another 50 km. You should know that there are long distances like in Germany High ways, between filling stations, in northern of Sweden. Some tenths km later I found a Statoil petrol station. 9 liters and a water bottle. I had 4 liters left, good for 80 km. At once two boys came up to me and admired my BSA. "You must had this for a long time"? "Yes" I said" since Umeå. That makes about 4.5 hours" was my answer, to their surprise. Then I prepared them for pushing if he wouldn't start. But he made it at once to my surprise. They thought of course that I was joking. Now my body was really tired and above all, my back was aching. I had to stand up in even intervals.
    
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BSA Lightning 650 1970 Driving back to Virsbo 2

Now I decided to visit Göran Olsson in Bollnäs. He had bought my Caddy -73 and we are still friends. To go there I had to turn to the right in Söderhamn in order to drive the 50 km to Bollnäs.  I had prepared this stop if feeling so. I had promised to call from Söderhamn. On the other hand I saw that my petrol would be enough to drive to Bollnäs. No stop because of eventual difficulties to start engine again. Better to fill up in Bollnäs and make my call at the same time. Before Söderhamn I drove through Hudiksvall. Here I bought my B-Ford 32 Roadster 1959 and wondered a little how the railway station look like today where we loaded the Roadster on a transport railway wagon. I didn't make any changes in decided route. Turning over to road 82 and then it was the last 50 km to Göran. I didn't really remember the way to him but knew that I had to drive over a river, Ljusnan. Then it would be some petrol stations. Here a bus forced me to the side and I had to brake heavily. This means that I tried to shift gear instead of press left pedal which is the brake. The engine stopped of course and I had to push my cycle the remaining 50 meters. Now I called Göran and he promised to show me the way. He came up to me with his 73 Caddy soon after I had filled up. He wanted of course to show that he was proud of the car. This Caddy is well known in Bollnäs and has won many first prices in car shows around. My BSA started at first kick and I followed after him draining of sweat. It was still 25° warm.  I felt glad for this stop for Göran's wife Ulla is a nice alert girl and fix everything to the best. She was still working so Göran suggested that we should buy pizza. We were lucky because we took the time to look in his garage at the 2 Cadillacs, 53 and 73 and his motorcycle, till Ulla came home. Now all were speeded up with food. Göran was sent to buy potatoe salad and then suddenly one bottle of wine appeared which became 2
and we had a nice chatting evening in their garden. I looked at his superb garage and remembered that I almost demanded hem to build it in order to buy my Caddy. He is very proud of the car and I must admit that it had never come in so good hands if I had kept it. He is a good new owner. After a shower I decided to go to bed and rest because I had still 280 km left for Virsbo.
       
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BSA Lightning 650 1970 Driving back to Virsbo 3

The morning afterwards I went up in good time after been sleeping all night. This is unusual because sleeping in a new bed is never good. I heard Göran and Ulla eating breakfast because she had to go to the butcher's factory were she works. Göran is retired after some rheumatism in his hands. This because of working with electrical high tension line constructions, winter and summer. This has destroyed his fingers. In spite of this he is not depressed and shares a good life with his wife Ulla.
I was nervous that the engine should abandon me and surely it did. I prepared to push but Göran wanted to try and the cycle started with a growl. Now I had petrol to reach Avesta. I choose road 272 over Ockelbo, Sandviken. There I now turn to road 68 for Avesta. I almost came to Hofors where the cycle once had been sold to Berggren 1972. Now I am the 11:th owner. See owner's story. Some tenths km before Avesta it was terrible road works. It didn't suite my BSA at all. After filling up and one Coca Cola in Avesta I had a well known road home to Virsbo and arrived to my Garage at 12:00. During the rest of he day I put my body in bed and took a well deserved rest. With thanks to my fine shining BSA which had taken me 710 km from Umeå without failing it's duty, only showing me some own little ways. This, just for I should not be to stuck-up.
Ok, oil change and solving clutch problem, gear problems (depends on clutch?) and discovering all other needs that an old motorcycle has. Spare part list, Shop Manual and find spare parts dealer.
As they say in TV ad channels. "Don't leave, sit down in your chair. We are soon back again" (next chapter).
       

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BSA Lightning 650 1970 Leading actions 1

In the purchase there was some catalogue material. This was the first I studied. In which way does the clutch function and how to open up and dismantle. At this point I didn't know that Gunnar had much more material for the cycle. Later I bought it togeteher with spares for 600 SKr. Before, this lack of knowledge, I ordered from BAS  motor those Shop Manuals and spare part register available. Then I started to study original handbook and Haynes book for BSA. I didn't find it to difficult.  First I had to buy the proper oil and change in engine and gearbox. Also changing filter. New filter was in the purchase. Started with gearbox oil. It is simple, just unscrew the drain plug. Oh My God, the thread followed with the plug. Just to unscrew this from the plug to. Lucky enough there was some thread left in the casting. After changing oil, I could screw it in place with help of a some LocTite 577. This replaces teflon tape or flax and is a thermoplastic substance and it is possible to unscrew. I had realized that a new HeliCoil thread must be put in place. Just to start up my computer and search for HeliCoil. There is a firm in Falun prepared to sell to private persons. ERGO-kraft. Here I ordered a kit box for UNC threads. The actual one was 1/2" 13 threads per inch. (ggr). Not to mismatch with 1/2" 12 ggr which is BSW. One must be very careful to measure inch threads when putting in HeliCoils. In a BSA it sometimes can be a none standard thread. Delivery time to get this box was one week, so I filled the gearbox with oil EP 90 and glued the plug. Later I changed this oil in gearbox to straight Castrol 50 and also for the engine. Now I started to open up for the clutch mechanism. To succeed with this you must first dismantle left foot rest. It is fastened with a left hand threaded nut. Besides one has to take away  the rear brake system. I used a drilling machine to unwind all the insex screws holding the cover. Here it was some long and some shorter ones. Only problem is to remember where they are situated. Click on picture to the left and I have done a map with arrows.
Three screws which are holding the springs for clutch pressure were later taken away.

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BSA Lightning 650 1970 Leading actions 2

First I noticed was that when I activated the clutch, the drive plates  were not plan and the rear wheel could hardly be rotated by hand. The clutch spring screws must later be adjusted up to bottom of the recess of the screwdriver notch. Now I could take away both type of clutch plates and I dismantle the twice 6 plates and saw that they were not plan. How do you say out of straight. This was established by putting them on a plan marble top.  This I had once saved from the small grocery shop which later become Guss Motor. See the article about Jans cars. A marble top from an old meat dish is guaranteed plan. The clutch disks noticeably were loose . I had also noticed that the opening movement of the clutch push rod was maximized to 2.5-3 mm. It was a requirement that the disks had to be plan. I had just to order new ones hoping they are proper. BAS-motor earned more money. During the time for delivery I stood one day straightening the old one's. Perhaps I could machine ground them plan to get them in good order. If you do that remember that when grinding the magnetic disc will draw the disk tight and then when you turn them, they will be as bad as before. Well it is a big opening in every disk. But after all knocking I succeeded to get the clutch function rather good. It was anyway hard to gear. I released a little on the  tight strainer for primary chain because I found it in my view to tightened. The threads of the inspection locks were both worn out or destroyed. BAS-motor again. 

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BSA Lightning 650 1970 Leading actions 3

Another thing was that the small axial needle bearing, see picture, which is the last part of clutch push rod, was mounted on the wrong side of the short pressure bar and could not in this place do it's job. Now I put everything together again. But I have not yet changed filter and oil. In order to empty the reservoir, the hose for oil was taken away just before the inlet to the pump. The oil poured nicely out. Opened also the bottom plug to the engine. Mostly to check that the thread was ok. It was ok. The filter was screwed out and a new one was put in place filled with oil. The bottom of the engine must also have 0,3 liter oil in order to start the return of oil at once. This is done through the plug of the timer hole in front of the crankcase. The filter of the oil tank was cleaned. Besides I washed the tank with white spirit ( today it has so many names). The most difficult of all this was to thread the rubber pipe on the steel pipe again. Good it is a suck pipe. It took a while but at last it was a success. The oil tank can take 3 liters 20-50 mineral oil. I saw that earlier it had only been 2 liters. There are 2 marks on the oil stick one in the middle. I filled up with 3 liters. Now I started the engine and what I felt, waited a eternity before the oil lamp went out. When restarting it didn't went out until 2000 rpm. Wonder if the oil was to thin. When warm engine it went out at 2200 rpm. A test tour showed that the good disks were ok, but gearing was still difficult. Later I got the new clutch disks. 3 of those showed to be  curved already when new. I bought good tools to open up the clutch at SKF-Momentum. They are reseller for bearings.  I combined the new good ones with the old and think that now my clutch is good. The big failure is the short movement of the push rod because one cannot produce plan disks. They punch 10000 in a batch which is poured into different wire baskets for cleaning from oil. At this occasion many of them will be jammed. Only my own theory, but I have seen when punching details. After that I had discovered that the push rod was in three parts plus a steel ball, I also changed it. It was much work before I got the proper length on this push rod. This length also depends of the total thickness of the disks. The thread in the outer locking nut was bad. This is used for getting the free play against the needle bearing. Much work before I had this acceptable. The threads of the inspection locks were bad so I bought new ones. Also the space for the locking nut against the lock. I had to open up one inspection lock according to the picture. Added one o-ring and a sealing rubber plate which was glued. I even ground the plane of the thread. Now it was free from the adjusting nut.

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BSA Lightning 650 1970 Points to be considered

Now I can give the first summary of all that was not good. 1. Oil pressure was a catastrophe after some time of driving. 2. It was not easier to keep the rpm up because gearbox sprocket had 23 teeth against normal 20 or 19. It must be changed. 3. This 23 sprocket could not be changed without extensive dismounting. More later. 4. Rear chain was  flaccid and was throwing sideways so much that it hit the chain cover. 5. Rear sprocket was a bit worn. Although I didn't need to change, but I did anyway. 6. Speedometer didn't show right speed. 7. Same thing for tachometer. 8. Signal horn was changed to mechanical one, as the electrical signal didn't function. 9. Front brake cable with brake light contact function bad. Light was always on. 10. Battery had wrong size. 11. Gear register worn (?). Didn't function good. 12. The right carburetor denied to flush. 13. Painting around the fastening of the petrol tank bubbles. 14. When the tank was painted they have not covered the filling hole and got paint into the tank. This will give paint flakes in petrol. 15. Later discovered that casting around crankshaft was broken and mended with three screws and plates. 16. Later one exhaust steering and one valve seat loosened in the top head. 17. Because of all work I became obliged to change threads to HeliCoils. I planed to change all threads  later.
All this, together with further experienced things, kept me busy all summer and autumn 2006. Still in October the cycle was not in order, in the way that I can trust it. I will tell you about these points and after works had to be. Of all points it is only one that the seller should have told me nr. 15. See picture. All others I was informed of or had seen. I am glad I succeeded to come home. PS summer 2007 seems everything to be in order.

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BSA Lightning 650 1970 Points which had to be done

I thought that the oil pressure was the first to act on. Later on I learned the function of the cycle as many opinions came up. Too thin oil. Too warm oil. Bad oil pump. Main bearing worn. As one easy can check oil flow, blocked oil pipes were excluded.
The first I did was to change to straight 50 oil. Castrol. The mineral oil 20-40 which I had bought was moved down to be oil for the primary chain. After some test drives I found out  that the new oil didn't affected on oil pressure. Next was the oil pump. It was dismantled and checked without finding anything wrong. Anyway I bought a new one, renovated, from BAS-motor. Now I got a small improvement. Oil lamp was lit at 2000 rpm. Could possible an oil cooler help? I got one from Gunnar in Umeå. I mounted it rather neat over the filter. Oil temp. was now 60°. Any improvement in oil pressure was not in sight because of this.
Now desperation over the situation, because I understood that it must be the main bearing in the right crankcase which was worn. To change that involved a total dismantling of engine. This is a work I had no experience of. When then a valve seat and a valve guide lost, it was nothing to pray for. A total dismantling started. At this time I also decided to fix all other points on my list.
Change gearbox sprocket to 19 teeth. Rear wheel sprocket. New drive chain. Renovate the bearing and change left hand roller bearing. Have HeliCoil in most threads. Straighten the rear wheel which was a little out of truth and of course everything else I detect.

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BSA Lightning 650 1970 Dismantling. Top, Cylinder.

I understood that in order to bring engine out of frame, I had to make it so light as I could. It must be dismantled as much as possibly. First empty all oil from engine and gearbox.

Then I started with the two mounting screws under the tank. These  2 screws had "eaten the threads in the tank. Mostly due to that there were no rubber bushings in the fastener. I threaded the worn thread with the nearest mm thread. One on the upper side under the rubber cover.  Petrol pipe connections were also taken away. From the carburetor I lifted up the throttle valve system and put them around the frame. The throttles were very nice with it's brass covers. The carburetors itself were also taken away.







Now I discovered that the axle of the right float didn't go through the float. I suspected that this was the reason that it was not able to flow. For security I bought a new one , in case it was destroyed. Anyway, this problem still exists and I don't know the reason.

Next on turn was valve cover, top head, valve system and cylinder head. These were easy job because I had done most of it when studying the valves earlier. Valve cover is hold in place by 6 insex screws. These were 5/16 20 threads/inch. Standard is 5/16" 18.  Here I made a failure when putting in 5/16 UNC HeliCoil with 18 threads/inch. It was solved wit new 5/16 UNC insex. 
The 2 screws in the middle had too less with material in the top head. They were not able to be changed. Before continuing, take away the exhaust pipes.




Now it was time to take away rockers and pushrods. In order to do this screw up all adjuster screws as much as possible, then it is easy to take away rocker axles and pushrods.  These rods seems to be fastened in lifter but it is only the vacuum caused by oil. I was cautious because I didn't know if lifters would follow with. No problem. the lifters are locked against this. Just bring the pushrods up. Before continuing remove the exhaust pipes. It's nuts may, rather hard, be in place, but take it easy it will be well done with suitable tools and a plastic hammer. When both valve and exhaust systems are away you can easily loosen the cylinder head bolts. Don't forget the one down in the pushrod hole. Be cautious of all nuts and washers, those who are placed under the bolts. They are a little thicker than normal to protect the surfaces of the casting. Put everything that belongs to each other in a plastic box and write a note what it is. It may be long time before you put them back! When I turned the top head upside down I saw that one valve seat and one valve guide was loose. I thought this had happened long before. This was the init for dismantling the engine. The top head was left to Motorteknik in Västerås.

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BSA Lightning 650 1970 Dismantling gearbox side 1.

Register side.
Here you have to take away the outer cover first. To do this remove the foot rest (may be left if you only shall take away the outer cover), gear pedal and kick arm. Then
loosen all insex bolts. Note their lengths and places. This cover don't need any sealing. Turn it back and tape it against the rear wheel. Next step is to loosen the connection for speedometer. Bring the connection for oil lamp away. Dismantle the ignition system normal or Boyer ignition. Note that it's small 3/16 BSF may be exchanged with M5 if threads are destroyed. Boyer contact breaker plate can be loosened from it's cone with the help of 5/16 UNF 24 thread/". Use as a puller. The breaker plate has this
thread and the bolt will press against center spur gear. This makes that you press the plate off it's cone. Loosen the kick spring and it's kick segment. The spring will fly away and the locking washer falls down. If you not already has done it. Do the same with gear system. Now it's time go inside and have a cup of strong coffee or tea and calm down.
The subject for inner cover is to separate engine oil from gearbox and it is equipped with a sealer which prevent these two oil volumes to mix. This cover is put in place with 8 insex bolts and have different lengths. Note carefully. Two are put outside low and 3 in the bottom of cover. Rest are around the edge. See picture and enlargement. Bring out the oil stick of gearbox area. When you bring this cover away you should
know that the middle camshaft spur follows with the cover. Now you have lost the initial ignition timing. This is not a problem, because you must learn to handle it. No difficulty.
Nothing is difficult if you know how to handle. Use a rubber or plastic hammer to get it away. As the cover loosens knock the kick axle in. Bring away the spur and mount it in its usual place. Don't bother about markings for the moment. Just notice that there are that kind. Look in the timer hole in the front of crankcase half and ensure that you see the timing marking. It looks like a big screwdriver groove. Picture former side. Don't mismatch with the round balancing holes. This cover you also turn backward and tape as you like. Study also the clutch mechanism. Pull out the push rod with a small screwdriver. Catch the small bearing ball if there is any. Note that it roles out on the clutch side. Now you can see the gearbox fastening nuts around gear register, and oil pump.  This is why this side is called register side. Screw away it's 5 nuts and feather washers. Note that there are no plain washers here. At remounting they must be tightened with 2.2 kgm. Before further action check that the register is put in neutral position. Knock on the conical axle on left side and the gearbox cluster comes out. Inside the gearbox volume there is a push rod which positions the gears. It is easy to take away or let it be.

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BSA Lightning 650 1970 Dismantling gearbox side 2.

Check the chain sprocket with it's nut and find out that it can be loosened with a suitable socket. Possibly a longer one. Now you understand that it was a good
decision not to dismantle the chain. The problem was to lock the sprocket so that the moment forces could be taken somewhere. Before look inside the gearbox shell. In the bottom you see the spur still is in place. This is the place where the conical axle for clutch wheel goes through. This spur is the place for chain sprocket. Now lock the rear wheel in a good way, far out on the diameter. Put on the socket and wrench the nut. When the nut is away you still cannot take away the sprocket. The spur, with the hole for clutch axle must be knocked into the gearbox volume. Now the sprocket gets loose from it's spline. Still
the sprocket hangs on it's simering. By hand you draw the sprocket through, the toothed hole of left crankcase, out of its place. This toothed hole has enough with space for a 20 teethed sprocket. In my cycle they had mounted a 23 one. To get this away you must divide the two the crankcase halves, or as I did ground the teeth of the sprocket. See picture. In picture above you see in the enlarged one how earlier owner had ground (chafe) away material from the simering and inside crankcase. In this way someone had forced in the 23-teethed sprocket. Not beautiful. I could also see that the drive chain had not space enough. It had worn a path in the casting and almost destroyed the locking device. Together with renovation of top head I ordered the firm to turn out 1 mm from inside left crankcase. A new chain and sprocket was very well justified.
But back to the right side. The camshaft nut has a washer with locking tabs. You must have the crankshaft locked through the timer hole according to earlier writings. Loosen the nut and pull out camshaft with your lovely puller. Note that there is a woodruff key. The camshaft cannot be taken away until you have divided the 2 crankcases. Left we now have to dismount the oil pump and pinion spur.

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BSA Lightning 650 1970 Oil pump, camshaft and it's wheels.

Now we are closing up inside the engine. Oil pump. Earlier I had taken away the one that was mounted in the engine and changed to a new one. Probably this had not been needed. But what the hell, when one is searching for defects, it is easy to start with the things that are easy to dismount. Oil pump is before register and bearings. We had earlier dismantled the speedometer connection. Now it's time for the pump again. It was easy to loosen as they earlier in the life of the BSA had replaced 1 stud bolt with an insex bolt. In other words, today the pump is hold in place with one stud and 2 insex bolts. The pump itself is screwed together with 4 small bolts. My experience is that never dismantle an oil pump, if not necessary. It is very difficult to mount all pieces again in good order.  I did so many times and didn't succeed to have all parts in good position. I could fell that it didn't turn without inner resistance part of the revolution. This is something that nobody believes in before they got the experience themselves. "That guy is a devil of a jerk". The expert renovated pump from BAS-motor was not perfect either. The driver of the pump (look at picture to the left former side) is mounted on crankshaft end with a key and a left hand threaded nut. This is true also for the pinion gear. Remember when taken the pump away you must consider the ball and spring for the back valve.
Now we start the work for dismounting the engine out of the frame. The drive chain and protection must be taken away. Hang up both ignition coils on the right shock absorber. The front and rear studs were no problem to loosen. On the other hand the rear engine mounting consisting of 4 bolts gave me lots of troubles. It must be something wrong in design because they were not possible to take away from their places. I was forced to loose even the 3-corner fastening plates. It took so long time that I today don't really remember how I solved it. Don't forget the oil pipe connection, from the tank, under the engine casting. It is put there with one small bolt. Even the oil sump cover must be dismounted. I must also mention that if your cycle has no studs holding the sump cover, be extremely careful with the suction pipe for the oil return. It reach under the level of the cover connection. Now it is possible to lift the engine from the front fastening and take with both arms, and all your strength, the engine out of it's place. Then you can study the wonder on your bench. Don't forget to put something under which will take care of all oil. In this case a packing left from my crayfish party. Later I drilled a hole in my bench where the crankshaft end could be put in. In this way the engine part was steady in it's place. Look at the picture of the empty frame. You can see how I arranged all parts. Coil springs, carburetors, cover to the gearbox, outer cover, middle camshaft wheel and oil pump pipe connections. Also the 2 black 3 edges plates for the rear engine mount. When engine is in place these plates are almost impossibly to reach for tools and hands.

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BSA Lightning 650 1970 Splitting the crankcase halves.

Before you divide the 2 crankcases, you have to study all the parts you have on your bench. Where all bolts and nuts are positioned. On the first picture to the left  you can see in the enlargement the 3 nuts which are in the bottom. The 3 bolt around the crankshaft are those holding the broken ring from the casting. The second picture shows the middle one nut between the 2 pistons. No screws from the right side. Now, take away all nuts and bolt  in the parting line. Now when dividing, take away the left half first. Don't use any screwdriver to make it easier. It is a sealing surface you are working with and here there is no gasket. Instead strike gently with a plastic/rubber
hammer. When this half is away look inside. You can see the bearing ring. From outside there are shims (for position of the triplex chain), simering, inner sealing ring and distance shims for the crankshaft axial play. Use the same type of puller (to be bought at a tool shop for 600 SKr.) You can see it in the picture. Then pull of the bearing from crankshaft.  Never use the screwdriver method. You only destroy the shims for axial play. To make it easier to pull the bearing, warm it with an heat air gun. Now turn the part around. Put the crankshaft end in the bench hole. Have 2 wooden pieces under to balance the shaft. Now the left crankcase is only hold by the slide bearing. Jerk this half with some strength. In the same time you twist it a little. It will loosen easily. Mount the puller once more in the pinion gear recesses and pull it off.  Now it just look like the next picture and you can amuse yourself by measuring anything you like. Bearing race and pistons. Even the cylinders, you can match to the pistons. My head was bored 04 (ø67.5 and gets 678 cc!). Both alike, which might not be sure if the engine earlier had been jerry-mended. The pistons (ø67) must have the same measure according to the borings. It is a rather big play between piston and bore. Remember that cylinder part is made of cast iron and pistons are made of aluminum.  It now showed up that the slip bearing was so loose that I could press it out by hand. Besides it was a noticeably play against the crankshaft end. This was the reason for the bad oil pressure. When I measured the bearing surface of the crankshaft, the outer pat of the surface was some hundred of a mm less. That means  it was conical. The surface was earlier grounded 01 according to my papers. The bearing and axial ring are so designed that they are locked against turning, lucky enough.

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BSA Lightning 650 1970 More work

I had one bearing ring with dimension for crankshaft grounding of 03. This means it has a lesser diameter than I need. I had one bearing grounded for 03 as reserve. I left  crankcase, crankshaft and bearing to a friend's son  He is capable of mounting this sort of thing. He turned the bearing to the right measure for oversize 01 and put everything in the crankcase. This was done in a few days, because he had bought a journey to Turkey. It took much longer time for Motorteknik to fix the valve seat and valve guide, the one that was loose. I also discussed with the Motorteknik man about eventual welding of the crankcase ring for the roller bearing. But he said one could get more problems if doing that. Let it be with its holding plates. It was so decided.
Now, when I have my engine in pieces (I have been taught) that always change bearings. They are proportionally cheap. For this reason I bought a new roller bearing. The same as that was mounted. This means that I showed the SKF shop "I want one alike". They had one week delivery. Later I got to know that it should be a bearing of the type C3. It was a normal bearing mounted. Well it might go well. The bearing was priced 634 Skr, a little cheaper than BAS-Motor.
When mounting the crankcases together, you have to start with the right part. Why, because you must prepare for the axial play when left part is mounted.
This is good to know about BSA design. The left crankcase cannot be mounted with the inner bearing part mounted on the crankshaft. The rollers don't slip inside the outer bearing ring. They fall down and interfere with the outer bearing ring. You must have the inner bearing part slipped in by hand to be complete. Well first I knocked in the outer ring from the inside of the case. I had a little marking left where the bottom ought to be positioned. Anyway, I was not sure that the ring was exactly perpendicular against the crankshaft line. Some distance shims were put on the crankshaft, otherwise the bearing will be to close to crankshaft balance weight, and you cannot get any grip for the puller. The bearing was warmed in place with my air heating gun. Then the crankcase was put in place and some bolts were mounted. With a mandrel the roller ring was knocked in the bottom of the crankshaft. You can easily hear and feel in the mandrel when it has it's proper position. But what about the (perpendicular) position of the outer ring? I took the mandrel and knocked in the outer inner edge of the bearing so far that the rollers now positioned against the edge. This will give me a zero in axial play, but my goal was to have the outer ring in the right position. To have this checked I mounted a measure clock (according to the picture) on the crankshaft end and put the measure pin against the outer ring (picture). In the case that the clock gave a change when rotating I brought out the mandrel again and so forth till I got zero. Next step is to get the right axial play. But how to know? It is supposed to be 0.07 mm. I reach after much work 0.1 mm.  For reaching this I had to dismount the crankcase several times and also the inner bearing, and mounted different shims. "Oh, my God", as the Americans say. With the measuring clock in place, I pulled and pushed the crankshaft till it was 0.1. Well don't think that everything is ready now. The camshaft must be put in, For this you must dismount the right crankcase again, but not the bearing. This is because the camshaft must be inserted before the halves are put together. I had chosen to wait with this till I had got a satisfactory axial play. So slip in the camshaft and don't forget the rotating bottom ring. Everything in the left case. Check also that the drivers of the bottom ring are hooked in the camshaft. Then slip in the camshaft in the right case and ask for mercy, that you have not forgotten anything . Check the axial play again for security. After this mount the broken ring with some blue tightening paste.

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BSA Lightning 650 1970 Clutch chain wheel

Now the point is to mount the triplex chain. Every detail must be studied before mounting to see if it is ok. I saw that the clutch wheel was defect. Never mount a defect part. Instead put a new one in place. In order to change this wheel it must be dismantled completely. As you see from the pictures it consist of many parts. The first you have to do is to press out the splined gear with the conical hole. It is pressed in the center hub. When this part is taken away save all rollers from the free bearing. Examine the bearing washer and remember on which side bearing metal was pointed. Now you have the hub with it's 3 conical screws on each side. See the banner picture this side. At remounting use LocTite 577 for their securing. This is better than the old fashioned way. Unscrew them and you get 2 rather big washers with a center hole and 3 around. Also holes for the screws. The three long screws are holding the springs. They can  now be taken away. Notice the design that keeps them from rotating with help of the higher part of the bottom washer. Now you have opened the most holy part of the clutch. Here you can see the place for damping elements and the rubber cushions. Well put it all together again with the new chain wheel. Remember to grease the bearing a little with bearing compound. Use this instead of molybdenum sulfide. It will destroy the friction ability of the disks.

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BSA Lightning 650 1970 Mounting the triplex chain.

We have now reached the point when it's time to remount the engine part into the frame before it will be too heavy. Fight with the rear holding, oil connection and the cover of the oil sump. Before you start to mount the chain you must mount the 19 teeth sprocket wheel and the gearbox. Mount then the drive chain to the rear wheel. For the moment don't tighten it. Let it hang loose.
Look at this picture. It shows the shims, that bring the crankshaft sprocket in the right position according to clutch  wheel. This you must test how many you need. Now lock the clutch wheel with it's center nut just a little. Put something straight against the two sprockets edges. For ex. rear side of a sliding caliper. It must lay fully on both surfaces. If not dismount and adjust with shims behind the crankshaft sprocket. When this is ready you have to mount both sprocket wheels with the chain in one go. Exactly the same way though the other direction. The splines of the crankshaft sprocket wheel must be knocked on in the same time as the clutch wheel is mounted. You must also be very carefully that the clutch wheel hit the woodruff key right. Otherwise the key will destroy the conical surface. It must be felt that the clutch wheel takes at firm stop. In that case it will match over the whole conical surface. Look at the picture how it looks like when you are ready.  The picture is inclusive the generator and chain tightening device. In order to get the cable from the generator you have of course put a cord through the hole. Then it is easy to pull it in place. Perhaps you also remember which place each cable will have in the cable connection . Here is a bad picture. Color against color. Because of Boyer ignition there is one empty place in the triple connection. Mount complete clutch with the right moments.
Now, you have the last chance to mount HeliCoils. But warning! Don't drill in the rear side of the left crankcase connection. Here there is not material enough. This is valid for four threads where the chain goes near the crankcase.

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