Author Topic: Manual advance system  (Read 9324 times)

Offline RDfella

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Re: Manual advance system
« Reply #45 on: 12.11. 2025 12:50 »
Or the mag gear that splits because of the hole for the adv/ret spring ....
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Online Radlan2

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Re: Manual advance system
« Reply #46 on: 12.11. 2025 14:22 »
       OK here is my current setup. At the start of this years biking season I had an issue with the manual A/R "mushroom" which operates the cam ring disengaging, causing the timing to retard too far causing very rough running and heat. This happened when out and about a few times, I tried a different mushroom but I think the housing in the end cover is worn so I made up a special mushroom to lock the cam ring in the fully advanced position. Starting and tickover are both good and reliable, this is my short rod motor with flat top pistons, 357 cam with twin carbs, timing set as per Eddie Dow recommended "twin tips" 5/16 BTDC. I will get around to changing the end cover and cam ring to the fixed type one day.  Might be a different story with a 9:1 motor.
     Chris P

Offline CheeserBeezer

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Re: Manual advance system
« Reply #47 on: 12.11. 2025 16:30 »
Been running my Velo (which ain't a plodder) for many years with those fine teeth, and rarely heard of failures there. I wonder if the fact that the Velo teeth are finer, effectively 'spreading the load' thereby less loading on individual teeth, therefore fewer failures? (I'd of course bow to your extensive engineering knowledge Andrew).
The slightest run-out on the armature shaft and they're knackered!

Online Rex

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Re: Manual advance system
« Reply #48 on: 12.11. 2025 18:54 »
BSA's become "knackered" while Velo's require the slight ministrations of an engineer.

Offline Adler

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Re: Manual advance system
« Reply #49 on: 13.11. 2025 11:50 »
hello Forum,
here is an Info from the www. Translated by Google from German.
"Fine teeth in a gear drive offer smoother running and more precise torque transmission, while large teeth allow for more torque at lower speeds. The choice depends on the application: fine teeth are suitable for applications where smooth and quiet operation is important (e.g., for precise control), while large teeth are advantageous where high power (torque) is required at low speeds."
Best regards, Manfred
Germany SE (Bavaria)
1950 A10 GF Plunger (and some German motorbikes from '33 to '54)

Offline Worty

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Re: Manual advance system
« Reply #50 on: 13.11. 2025 14:13 »
Large teeth mean I can get through my burger quicker *smile*
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Online Rex

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Re: Manual advance system
« Reply #51 on: 13.11. 2025 17:46 »
Allegedly Bert Hopwood described the timing and gearbox pinions on BSA's and Triumphs as "mangle gears".
You have to be of a certain age to understand the reference. *eek*

Online Bsareg

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Re: Manual advance system
« Reply #52 on: 13.11. 2025 22:30 »
Allegedly Bert Hopwood described the timing and gearbox pinions on BSA's and Triumphs as "mangle gears".
You have to be of a certain age to understand the reference. *eek*
When I read that I could hear the mangle gears turning. 😁
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Online Joolstacho

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Re: Manual advance system
« Reply #53 on: 13.11. 2025 22:45 »
I can picture my dear ol' mum turning the handle now.

Offline Adler

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Re: Manual advance system
« Reply #54 on: 14.11. 2025 06:15 »
In addition to my an the previous posts I would like to post a good example for smooth (?) and quiet (??) operation and therefore precise control on the left side and high power (torque) on the other - Made by Triumph  *smile*.
Best regards, Manfred
Germany SE (Bavaria)
1950 A10 GF Plunger (and some German motorbikes from '33 to '54)

Offline Worty

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Re: Manual advance system
« Reply #55 on: 14.11. 2025 08:47 »
FYI.  The spelling of 'mangel' on the machine is, apparently, the Dutch spelling of the word from which we get our 'mangle'. 

I do like those cogs. *dribble*
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Online Joolstacho

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Re: Manual advance system
« Reply #56 on: 14.11. 2025 08:50 »
What... about 20rpm?  *eek*

Online Joolstacho

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Re: Manual advance system
« Reply #57 on: 26.12. 2025 22:30 »
It looks just like the etching press we used at Art School too.