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Re: Rectifier

Posted: Sat Nov 09, 2024 5:07 pm
by Ivor Collins
Thanks Paul and Richard for your replies.
I thought these photos might better explain what I’m trying to convey.
You wiring harness phot clearly shows the two green/whites are joined before being rectified, as are the green/blues.
As the wiring diagram shows, the alternator output supplies the rectifier but ALSO supples the lighting switch Unrectified
Hope this is clear and you’ll let me know what you think

Re: Rectifier

Posted: Sat Nov 09, 2024 7:27 pm
by will_curry
What you are missing is the internal connections of both ignition and lighting switches.

The connections from the rectifier to the lighting switch are connected to the ignition
switch via the black lead from terminal 5 to terminal 18 on the ignition switch. This is
connected to the alternator via terminal 17 when the switches are set accordingly.
At no time is any of the alternator output directly connected to the lighting circuit.

The effect of all this wiring is to switch in the second two pairs of coils to augment the
first pair only when the headlamp is alight and so reduce the risk of the battery being
over-charged. It's a nice idea but it's not that successful.

If you're not already a member of the club it's well worth joining as there is a good
deal of information available to members on the club's website.

Re: Rectifier

Posted: Tue Nov 12, 2024 9:54 am
by Ivor Collins
Thank you Will.
Having checked out the internal connections, I can now see, it’s as you say, that it’s a contrived route for switching the coils, the AC routed up to the switchgear makes no connection to the ‘live’ circuits of either lighting or ignition.
Phew! It makes way more sense now.
Now my challenge is wiring up a Suzuki dynastart to the Arrow, I have it fitted and its starting the engine great but need to sort out the correct terminals and connect it up for charging and field circuit🤯

Re: Rectifier

Posted: Tue Nov 12, 2024 1:41 pm
by will_curry
Glad it was helpful.

I'm interested in your dynastart project and I'm sure there will be others too.
Can you post the details and some pictures please?

Re: Rectifier

Posted: Tue Nov 12, 2024 7:09 pm
by Ivor Collins
I found the Suzuki GT 185 to be a good donor for the project (the one without external lugs), it’s only slightly longer and fatter than the old alternator. The standard tin cover is large enough in diameter but would need to be extended and the gear change lever cranked slightly.

The crankcase door has one out of the three original alternator studs matching the dynastart fixing positions but you’ll need to weld in lugs to accommodate the other two. Countersink the fixing holes where the door attaches to the crankcase and replace the existing studs with screws to keep the unit close up to the engine
I then machined an annular recess in the door to accommodate the dynastart case nose to ensure concentricity but this is not essential.

The rotor comes with a tapered bore but this can be machined parallel to fit the Ariel crank and a new keyway cut to suit. I replaced the central bolt with an Allen bolt and countersunk it into the end of the rotor to reduce the overall protrusion.

I’m still not clear on the charging circuit wiring but it looking good so far.

If you need any other info/photos let me know.

Re: Rectifier

Posted: Wed Nov 13, 2024 10:39 pm
by will_curry
Thanks for the information and the picture. It's food for thought for the day my knees finally give out.

I found this link to a website with a manual with details of of the dynastart wiring and the rest of
the bike wiring too:

https://www.oldjapanesebikes.com/mraxl_ ... /index.php

Re: Rectifier

Posted: Wed Nov 13, 2024 11:54 pm
by Ivor Collins
My thoughts too Will, I’m future proofing now so I’m ready for that day🥴

Thanks for the wiring diagram but my problem is more the fact that this is a bare Dynastart with a variety of terminals, just need to work or what goes where and then connect to a regulator.

I understand there is a club member with an even simpler starter design, I’m hoping to see it posted one of these days🙏

Re: Rectifier

Posted: Thu Nov 14, 2024 12:04 am
by Simon.Gardiner
If we could get enough info together it would be nice to turn it into a 'HowTo' pdf doc in the online library.
(I've done a few of these already and there are a couple more on my 'todo' list when I get a few weeks free from other things :roll: ;) )

SG

Re: Rectifier

Posted: Thu Nov 14, 2024 9:46 am
by Roger Gwynn
Denis 'Smokey' Hearn has been working on a more conventional type of starter for some time now, I suspect that the project has stalled though, I don't know if he is on the forum. Can pass on contact details if anyone wants yo contact him.

Re: Rectifier

Posted: Thu Nov 14, 2024 8:59 pm
by Ivor Collins
Hi Roger
I’d be keen to compare ideas with Denis if you’d pass on contact details please