The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: SteveHem on 11.03. 2022 18:46

Title: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 18:46: Hi All,

I wondered if i could pass by you all what im doing in an attempt to time my ignition. Ive tried 4 times and just get backfires when i kick it over.

1) Both plugs out
2) Timing cover off
3) Auto advance off
4) Select 2nd gear with rear wheel off floor
5) Finding compression stroke on left cylinder primary side (blowing out plug)
6) Pencil down the plug and marking TDC
7) Tapping wheel backwards until 5/16" or 7.9mm and marking it on the pencil
8) Put thin paper in between point on the mag
9) Turn the points clockwise until the paper releases
10) Wedge the auto advance unit open
11) Carefully do up the nut while putting pressure on points to stop movement
12) Plugs back in and leads attached
13) Wedge out the auto unit

Then im kicking and just get bangs! Any idea where im going wrong?

Thanks Steve
Title: Re: 58 A10 Timing Probs
Post by: Billybream on 11.03. 2022 19:22: Most probably timing on the wrong cylinder, try swopping the HT leads over
Title: Re: 58 A10 Timing Probs
Post by: groily on 11.03. 2022 19:46: When points open on lower cam lobe about 4 o'clock - ish, the rear or gearbox side pickup sparks. Upper lobe, ten-ish, is the front pick up. You don't say which lead you have off which side of the mag, so HT leads reversed is very possible per BillyB's comment.
When setting piston position, always best to go back beyond the right spot and come up to it 'Forwards' to eliminate backlash.
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 19:48: Could def try that!

I did take a pic of the leads before removing them though.
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 19:55: That was it! Lovely, thanks..
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 20:00: I think ill get a TDC plug tool and mag static timing led tool to get it just right.
Title: Re: 58 A10 Timing Probs
Post by: Triton Thrasher on 11.03. 2022 20:25: Don’t you check the timing after you think you’ve set it?
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 20:44: I have been and that's why i was confused. Dont think using a pencil flapping around is the best way to get accuracy so will look forward to getting the plug tool
Title: Re: 58 A10 Timing Probs
Post by: JulianS on 11.03. 2022 21:11: I like this factory hint on timing an iron head twin.
Title: Re: 58 A10 Timing Probs
Post by: muskrat on 11.03. 2022 21:19: G'day Steve.
Glad you got that sorted.
Now get over to Introductions and give us your A7/A10 story.
Credit card number and pin is optional *smile*
Cheers
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 11.03. 2022 22:01: Will do haha... I have a great story about my B31 with an A10 motor, i will share tomorrow..

Thanks Steve
Title: Re: 58 A10 Timing Probs
Post by: Triton Thrasher on 11.03. 2022 22:52: Quote from: SteveHem on 11.03. 2022 20:44
I have been and that's why i was confused. Dont think using a pencil flapping around is the best way to get accuracy so will look forward to getting the plug tool

Marks on a pencil are accurate enough.

Much more than accurate enough to get the engine started.
Title: Re: 58 A10 Timing Probs
Post by: RichardL on 12.03. 2022 00:48: I think most of us are leaving the ATD on loose blocked to full advance while setting the points. Maybe it doesn't matter, but the less fumbling with the thread and horseshoe washer while the points are in position, the better, I think. By "thin paper," may we assume you mean rolling paper, which is thinner than most? I like to attach a clip lead to it as weight so it falls out on its own, rather than me trying to judge it while doing other things with my hands. I'm sure they probably work fine, but I don't care for the idea of the plug-hole stop device. It goes in at about a 45 degree angle, so break out your trigonometry.

Here is a picture of my "pencil." Graduations are 1/32" printed from AutoCad.

Richard L.
Title: Re: 58 A10 Timing Probs
Post by: groily on 12.03. 2022 10:07: Quote from: SteveHem on 11.03. 2022 19:48
I did take a pic of the leads before removing them though.
Ah yes, but you didn't know probably which side the last bloke timed it on! So well done, sorted.

(I'm not sure if folk here follow a particular rule of thumb, but I time all mine with the rear pickup to the rh cylinder ('R to R'). Stops me getting muddled up, which is all too easy these days.)
Title: Re: 58 A10 Timing Probs
Post by: RDfella on 12.03. 2022 11:57: Quote
Here is a picture of my "pencil." Graduations are 1/32" printed from AutoCad.
Yes, but is it accurate? I have four printers in my office, and they'll all print the same item a slightly different size.
Reminds me of a good mate (now departed) who was into bore-hole drilling. Needing a fresh supply of pipe he drew around a short end and faxed it off to the supplier. When the pipes arrived they were completely the wrong diameter. *eek*
Title: Re: 58 A10 Timing Probs
Post by: RichardL on 12.03. 2022 13:37: RD,

Not my style to create such a thing without checking the result.

Richard L.
Title: Re: 58 A10 Timing Probs
Post by: fffcycles on 22.03. 2022 15:27: Just got to timing my A7 LS and using my aircraft magneto timing box. Works on gauging impedance with an audible tone when the points open. Nice tool for $35 usd.
Frank
Title: Re: 58 A10 Timing Probs
Post by: SteveHem on 23.03. 2022 09:15: I ended up ordering a ignition timing buzzer/led box of tricks along with a TDC plug plunger tool and doing the timing again.

I actually made a 22 min video of the operation and put it on Youtube as i couldn't find another similar. Obviously im no pro and this shows in the video haha but im sure it will help people in the future...

https://youtu.be/erKbR_6-Tvc