1960 A7 Shooting Star Sprocket Sizes

[Swarfcut]

Brian.. Thanks for that reminder.  Longstroke timing gears look the same as shortstroke gears, but all are different.

 Crank pinion...timing dot to keyway position differ from shortstroke pinion.

 Intermediate gear....marks different as above.

 Camshaft gear....peg for breather sleeve in different position.

 All this is somewhere on the Forum, a good few folks have had this problem.

 Timing disc check will tell if the basic cam timing is correct, but also confirm the bike has a 356 cam.

 Worth checking valve springs look correct, as weak or missing (inner) springs can limit performance.

   Cheers.

   Swarfy.

[Peter in Aus]

This may help, it is on the forum some where but this a copy I made of it
Peter

[sheffield steel]

This is possibly a stupid question but here goes, I don’t mind looking stupid...
A few people have mentioned a tight engine could be contributing to the problem which seems logical.....but how tight is tight????

I’m turning the engine over using a ratchet about 8” long on the end of the engine sprocket (I have a nut securing the sprocket on the cush drive not C-Spanner thing), there’s no primary chain or rocker box fitted and the plugs are out. All the timing gears, oil pump, mag and dynamo are fitted. The effort required isn’t huge but it doesn’t exactly spin freely. I certainly can’t turn it by hand on the cush drive.

It’s probably about 4 years since all the bottom end was rebuild by SRM, but I reckon I’ll have only done something like 1000 to 1500 miles in that time.

[RDfella]

I would expect that to turn by hand with a reasonable grip of the cush drive (far less grip than opening a jam jar).

[berger]

well what can I say , apart from if you were me I would find a nice hard  block of wood and smack the end of the crank nut and see if it loosens any when turning, I would say that is tight but wether it is bore to piston  or crank end float who knows without investigating. you could drop the timing gears off to make sure it isn't tight on the bushes. the crank pistons and rings on there own should turn easily by hand.

[sheffield steel]

Ok thanks, further investigation required....

Next stupid question....

I’ve removed the carb (which is an Amal 376/208) which is 1” bore, however the inlet manifold is approx 1” 1/16 diameter (28mm).  Is this correct?

Bike is a 1960 A7 Shooting Star

[berger]

Sheffield steel yes 1"  is correct

[sheffield steel]

Thanks
All the info I can find says it should have a 376/289 mono lock fitted not a 376/208. Both are 1” bore so any idea what the difference is and if it would be worth fitting a 376/289?

[berger]

not sure on that one , think it is to do with jetting but any 376 jetted to shooting star spec will do 270 main jet 30pilot needle106 needle position 3 from top. carb slide 3/1/2, I also think that having the head a little bit bigger than the carb is good for turbulence and was done on purpose