26-07-2020, 03:52 PM
Hello All,
Thank you for all the replies. Just to confirm the the scooter does have a magneto ignition system and is 6V +ve earth. There was a full wave metal rectifier but one section of this was s/c and I have now replaced the metal rectifier with silicone although I've not connected it. I don't currently have a battery for the scooter. I have a downloaded copy of the user manual in which it warns you not to start the engine without the battery connected as it will burn out the bulbs and "damage the rectifier". I'm not sure if the silicone rectifier would be damaged in this way but I haven't tempted fate by trying. Without a battery or the rectifier connected the engine can still be started so enough current must be being induced in the primary of the ignition coil. I have made up a battery from five Ni-Mh AA cells but this was simply to test the lights and switches. I'm not sure connecting up the rectifier to both the LT coil and then this battery would be a good idea. My main reason for not leaving the ignition system "as is" the fact that the existing points have been on the scooter for around 50 years. There was a little corrosion on the points themselves and a little wear on the cam follower. A "new" set might be hard to get not to say expensive. Also as had already been said using a transistor to do the switching would hopefully give improved starting and idle. Mention was made of the condition of the capacitor across the points. It reads OK but it too has been lying for about 50 years. I have considered replacing it although again not with an original. Mention was also made of asking on motorcycle forums. I have joined the "Vintage Motor Scooter Club" as they are the only group that seems to cater for my scooter but they don't have a forum. I think the other one I looked at was the BSA Owners Club forum but there was very little on that. I do not have the scooter running all the time just now as I still have sum welding to do and I like to do this with the tank empty and the carburettor removed.
Thanks for doing this Trevor. The big issue seems to be whether this can be done with a magneto ignition system. If the battery does need to be connected to get it to work (and it looks as if it does) it will be a while before I will be able to try it but I will try it if you can remember what to use as the second transistor. I'm still wondering how the current induced in the coil as the flywheel spins will affect it.
Regards,
Ken.
Thank you for all the replies. Just to confirm the the scooter does have a magneto ignition system and is 6V +ve earth. There was a full wave metal rectifier but one section of this was s/c and I have now replaced the metal rectifier with silicone although I've not connected it. I don't currently have a battery for the scooter. I have a downloaded copy of the user manual in which it warns you not to start the engine without the battery connected as it will burn out the bulbs and "damage the rectifier". I'm not sure if the silicone rectifier would be damaged in this way but I haven't tempted fate by trying. Without a battery or the rectifier connected the engine can still be started so enough current must be being induced in the primary of the ignition coil. I have made up a battery from five Ni-Mh AA cells but this was simply to test the lights and switches. I'm not sure connecting up the rectifier to both the LT coil and then this battery would be a good idea. My main reason for not leaving the ignition system "as is" the fact that the existing points have been on the scooter for around 50 years. There was a little corrosion on the points themselves and a little wear on the cam follower. A "new" set might be hard to get not to say expensive. Also as had already been said using a transistor to do the switching would hopefully give improved starting and idle. Mention was made of the condition of the capacitor across the points. It reads OK but it too has been lying for about 50 years. I have considered replacing it although again not with an original. Mention was also made of asking on motorcycle forums. I have joined the "Vintage Motor Scooter Club" as they are the only group that seems to cater for my scooter but they don't have a forum. I think the other one I looked at was the BSA Owners Club forum but there was very little on that. I do not have the scooter running all the time just now as I still have sum welding to do and I like to do this with the tank empty and the carburettor removed.
(26-07-2020, 01:01 PM)Murphyv310 Wrote: Hi.
Here is the circuit and I'm not sure if this will work on a magneto set up.
Thanks for doing this Trevor. The big issue seems to be whether this can be done with a magneto ignition system. If the battery does need to be connected to get it to work (and it looks as if it does) it will be a while before I will be able to try it but I will try it if you can remember what to use as the second transistor. I'm still wondering how the current induced in the coil as the flywheel spins will affect it.
Regards,
Ken.