Author Topic: mag sprocket  (Read 813 times)

Offline emilios

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mag sprocket
« on: 10.12. 2009 17:14 »
Hi i just notice that my mag sprocket is a custom made autoadvance but is not working on autoadvance mag..
My magdyno is  hand manual advance/retard..
Will that cause any problem??
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Online groily

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Re: mag sprocket
« Reply #1 on: 10.12. 2009 17:38 »
I think it's been disabled Emilios, and hopefully made rigid so the pinion can't shift relative to the fixing bolt. (Unless there are other bits you've taken off which weren't in the pic). It looks like the standard item without its weights and springs - but with a big collar between the outer yoke and the middle of the gear as, presumably, a distance piece to lock it up. It might or might not have retained its auto-extract system on the fixing bolt depending on exactly how the guy did the bodge.
So you only have the manual method, which is what you want with a manual mag.
Plain pinions in tufnol or alloy are available (much cheaper than ATD units) should you have doubts about the teeth on the one you have. If there is any question, I'd get a new one because when they fail they are a pain.
Bill

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Re: mag sprocket
« Reply #2 on: 10.12. 2009 17:50 »
Just blew up the pic of your pinion. Although the resolution makes it hard to see as clearly as these dimming eyes would like, I think there are signs of tooth decay, probably beyond what the average motorbike dentist would be happy with. If there are any teeth, even just one, which looks more tired than the others, thinner, more pointy and less height, steps in its profile looked at side-on . . . . It's a sure sign of trouble looming.
Bill

Offline emilios

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Re: mag sprocket
« Reply #3 on: 10.12. 2009 18:06 »
Actualy is one tooth that looks little broke...
Could this caused bike stop suddenly??
Cause that what happend to me.
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

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Re: mag sprocket
« Reply #4 on: 10.12. 2009 18:58 »
Hard to tell. Depends if the tooth is still capable of engaging the driving gear; if it is, then that didn't stop it dead. If it isn't able to mesh, then depending on the wear of adjacent teeth etc and whether they can 'carry' the missing tooth, it may rapidly become many teeth out  . . . and stop the thing, often with a loud backfire or three.
Normally, when the pinion goes, several teeth strip, leaving a toothless arc on the gear . . . no way back from that!
Bill