b40 engine problem

[alwaysintheshed]

hi folks, nearly finished restoring my 61 b40, engine was rebuilt by last owner before i got it (believe me i checked) so it has yet to be run. whilst i was i was doing the tin work and the rest of the bike i kept kicking it over to stop it from seizing and spraying light oil down on the valves and piston crown, trouble is now ive left it for a while i cant kick it over and the piston is right at the top of its stroke, kickstart just wont budge, anything i can do other than strip the thing down? any sugestions will help, many thanx in advance mark.

[Goldie]

Have you tried putting it in gear and then rocking it backwards and forewards with the spark plug out to try and free it up?

If that does not cure the problem then you will have to take the outer cover off the engine to make sure that the kickstart quadrent has not jammed up for some reason.

If not, then you may have to look to see if there is a fault inside the gearbox causing it to jam.

I would not think that the piston has siezed up if you have been putting oil down the bore.

[alwaysintheshed]

ok got a chance to have a look at it today, put it in gear and rocked it back and forth no joy there wont budge, can only seem to get first gear through so maybe the gearbox is jammed not allowing the engine to turn over ? does that sound possible?
got so many little jobs to do to finish it seems like it will never be done,

[chris p]

if you,re not sure whether its the engine or gearbox thats jammed dismantle the primary drive and try to turn engine and gearbox individually

[alwaysintheshed]

ok took the primary side cover off and its easy to see why its been jammed, the clutch spring nuts have been catching on the primary cover, good news is now the engine will turn over (phew) bad news is the clutch basket seems to far back and doesnt turn when you kick it over , even in gear, i take it its meant to?
havent worked on to many bsa's before as this is my first restoration
many thanx for all your help so far.

[alwaysintheshed]

ok checked the large clutch nut in the centre and this was loose so tightened it up with a new tab washer, when you turn the engine over my moving the nut on the end of the rotor the primary side all turns , but when you kick it over only the clutch basket centre turns, just need to know if its meant to do this or is there something wrong??, engine sounds like its all moving freely so thats good and it has good compression
cheers mark.

[L.A.B.]

ok checked the large clutch nut in the centre and this was loose so tightened it up with a new tab washer, when you turn the engine over my moving the nut on the end of the rotor the primary side all turns , but when you kick it over only the clutch basket centre turns, just need to know if its meant to do this or is there something wrong??,

That depends whether you mean with the clutch plates, pressure plate, springs and nuts all replaced and springs tensioned?

With everything reinstalled, the kickstarter should be turning the clutch basket (and primary chain and engine sprocket on the crankshaft) as well as the mainshaft and clutch centre because the plates should be gripping each other? If the comlplete clutch assembly doesn't turn when you operate the kickstart then something isn't right? The hub could be loose on the mainshaft taper, if so, then the woodruff key is probably missing or broken, but the tapered joint itself should of course transmit the drive, and not the woodruff key.  

  

[Goldie]

If your clutch centre is turning which is connected to the gearbox mainshaft, and the clutch basket "chain wheel) is not turning with it, then i would suspect that the clutch plates springs are not done up tight enough, or the plates are knackered.
Also make sure that the clutch push rod has half turn clearence on the adjusting screw and lock nut. You do this operation after you have tightened the clutch springs so the plates lift evenly.

Do you not have a Haynes manual you can refer to. I would imagine that a BSA C15 manual would be near enough the same, because a B40 is only a jumped up C15.

[L.A.B.]

Do you not have a Haynes manual you can refer to. I would imagine that a BSA C15 manual would be near enough the same, because a B40 is only a jumped up C15.

Photocopy B40 workshop manuals (and parts lists) should be available from either Bruce Main-Smith: http://www.brucemain-smith.com/ or British Motorcycle Parts:   http://www.britishmotorcyclespares.com/

[Goldie]

http://cgi.ebay.co.uk/BSA-Unit-Singles-Haynes-Owners-Workshop-Manual-1958-72_W0QQitemZ260384280673QQcmdZViewItemQQptZUK_CarParts_Vehicles_Manuals_Litterature_ET?hash=item260384280673&_trksid=p3286.c0.m14&_trkparms=72%3A1683%7C66%3A2%7C65%3A12%7C39%3A2%7C240%3A1318