About a year ago I imported a 1932 Sloper SV from the UK. Upon arrival I did all the usual stuff. Added gas to the empty tank, replaced the oil and added air to the tires.
Since it was sold as a non-runner I wasn't surprised when nothing noteworthy happened when I kicked it over. The first test revealed a very small spark every once in a while. A leak down test revealed a leaking valve cover.
I took the jug, piston and valves to a machinists friend and sent the mag/dyno off to be repaired.
The jug was returned with new valves, guides and valve seats and new piston rings. The threads for the valve covers were weak and worn but he cleaned them up the best he could. I had obtained new valve covers which were installed.
The mag came back producing a very robust spark at regular intervals....and hopefully at the right time.
My nephew, affectionately referred to as "the designated kicker", and I worked on it from time to time all summer trying to figure out why it wouldn't start and what we missed. We finally gave up and put it away for the winter.
Well, it's back out again. While I haven't actually started working on it, I have been doing some research.
It was then I see pictures of SV Slopers with the spark plug installed in the intake valve cover and a threaded plug in the hole over the piston.
Could this be the reason I can't get this bike running? AND where can I get the correct valve cover?
I always thought Jugs were something quite different?
I wonder what engine you have? A picture and engine number would be good.
The 1932 model had a separate cylinder head with no valve caps, just a spark plug hole in the centre.
The earlier models did not have a separate head, and had 2 valve caps and a compression tap in the centre.
Whatever, I think your engine should still start. Do you have good compression?
Is the spark plug getting wet? Are the valve timing marks on the pinions lined up? Do you have a spark? A neon tester would be a good start, but not conclusive.
Mag points should be just opening (use a cigarette paper) when the piston is about 7/16" BTDC on full advance?
Is there much play in the throttle slide when about 1/8" open? Is the choke slide bottoming?
Let us know, and we'll take it to the next step.
Thank you for the reply.
The number stamped on the left side of the crank case is A10-168. I tried to post a picture but it was to large. I will post them somewhere and post a link.
The jugs/head are one piece.
My engine definitely has 2 valve caps
I did not do a leak down test after I got the head back from the machinists. The "thumb on the spark plug hole" test proved I had much more compression than before. That will be my first test once it's back on the lift.
As I recall the plugs were getting wet and the valve timing marks are lining up.
Yes, I have spark. The mag was rebuilt because the spark was very weak.
I DO need to get a neon tester.
I will be checking back in once I get the bike on the lift again.
It seems from what you wrote the engine is not from a 1932 model.
What about moving the spark plug over to the inlet valve?
This should be a picture of the 1932 BSA
https://www.dropbox.com/scl/fi/ltsmi0c5j5isv60d3y7po/Photo-Jul-03-2025-5-05-20-PM.jpg?rlkey=oifw3jblngun76ii9rze2aq2i&st=qj00qrvi&dl=0
The A10 prefix engine is from a 1933 season M33-10 with that low number would have been made in late 1932. The M33-10 frame number also commenced A10. Catalogue page below.1932 model numbers commenced with letter Z.
The parts catalogue shows these had a separate head and no valve caps. The head part 24 1068 and cylinder part 24 1065 shown in the second photo.
The paperwork that came with the bike (V5CW) says the chassis VIN is A10246 and the engine VIN is A10168 if that helps.
From the above, it would seem that someone has fitted an earlier barrel/head to 1933 crankcases, as the 1933 head was definitely separate.
Your head would have had a compression cup where your spark plug is. This is a brass cup, to which petrol was added in very cold weather, to thin the treacle thick oil on the bore, and ease kickstarter operation.
As you suggested, I believe that your engine top end would have had the spark plug screwed into the inlet valve cap.
Perhaps you might drill and tap you existing cap? However, I see no reason why it wouldn't start with the plug in a central position, but who knows?
The Part No. is R31, and you might try Cornucopia in Germany, or British Only Austria.
Not that this helps much, but it would seem that your Jug is from either a 1931 557cc or 493cc,or maybe a 1932 499cc or 557cc.I don't know which one of these would fit 1933 crankcases, as they were all different. Did you measure the piston?
It seems odd that it won't start as you seem to have everything needed. As I suggested, check the ignition timing on full advance. I would also physically check the valve timing against the diagram, and familiarise yourself with the pilot and pilot bypass orifices. Don't poke a wire down them. Check for blockage with an aerosol with extension tube. Your spark should jump at least 1/4" in air.
Splendid looking Motorcycle, by the way.
Thank you for the reply. I have a set of used, well used, covers that were replaced with new covers. I'm planning on sending one to a machinist to have a spark plug hole1 drilled and tapped. Just to see if that helps.
The bore is 3.3465"
It's been several months since we locked at the bike so I need to start from scratch.
3.3465" is 85mm, so it looks like your Sloper is 550cc.
I've just had another thought. It might be worth draining the crankcase, in case there is an excessive build up of oil. The drain screw for this is the upper of the 2 drain screws. If excessive oil is present, this will slow down the spinning of the engine and may oil up the plug.