The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Snowy on 05.04. 2020 10:11

Title: A10 misfire - tickover and lower gears
Post by: Snowy on 05.04. 2020 10:11
Asking for experience before I end up doing unnecessary investigations!
1961 A10, Boyer ignition, non-magneto.
Starts a treat, but on tickover, even after warming up, suffer misfire through carb.
New NGK plugs, and 500K ohm plug caps (as suggested with Boyer ignition?) fitted
Yet to do valve clearances, although the way she runs in the higher gears across all throttle openings indicates no issues with fuelling or breathing.
Timing - I have yet to find any info on timing the ignition with Boyer unit fitted.
Any thoughts or ideas greatly appreciated so I can "play with confidence when off shift again!
Snowy.
Title: Re: A10 misfire - tickover and lower gears
Post by: muskrat on 05.04. 2020 18:33
G'day Snowy.
I have Boyer on both mine. Make sure it's getting the full 12 volts, if it drops the unit will go to full advance hence good at revs, crap at idle. I know they (Boyer) say it will work as low as 10 volts BUT!
 The only real way to time them is with a strobe and degree wheel. Around 34 (+/- 2 depending on tune) degrees BTDC full advance should work. I have permanent degree discs on both. The Cafe is easy with the open primary, the plunger needs the cover removed.
Cheers
Title: Re: A10 misfire - tickover and lower gears
Post by: morris on 05.04. 2020 19:29
Back that up. Even at 10.5-11V it can start to misfire.
Have you got the DVR (or similar) belt drive?
The ignition takes quite a lot of the power the dynamo produces so it needs to be in perfect order and preferably fitted with a belt drive.
Even with a belt drive, when there's a less efficient regulator in the circuit, the battery still struggles to keep its voltage. I found that the only good regulator is the one that DVR makes.
Title: Re: A10 misfire - tickover and lower gears
Post by: Snowy on 09.04. 2020 17:28
Thanks for all advice, seems a logical place to start and common line of thought!
Bit the bullet! DVR2 just ordered.
Boyer Power Box regulator currently fitted, looking at the ammeter there's no real current till about 1/2 way up the rev range, so lets try and see!
Title: Re: A10 misfire - tickover and lower gears
Post by: morris on 09.04. 2020 18:32
I bought this gizmo some time ago. It shows a green led when the battery receives decent charging current and doubles up as emergency torchlight.
With the TEC regulator that was on the bike, the green led would never go on, not even at high revs.
The DVR 2 made the green led go on at just above tickover
 *beer*
Title: Re: A10 misfire - tickover and lower gears
Post by: Snowy on 12.04. 2020 16:12
I bought this gizmo some time ago. It shows a green led when the battery receives decent charging current and doubles up as emergency torchlight.
With the TEC regulator that was on the bike, the green led would never go on, not even at high revs.
The DVR 2 made the green led go on at just above tickover
 *beer*
What a brilliantly simple solution, if you have a Optimate charger! :(
Suppose I could cut the dedicated connector off and fit standard 12v socket and plug?
Anyone know of anything similar that does the same thing?
Title: Re: A10 misfire - tickover and lower gears
Post by: Snowy on 12.04. 2020 16:40
Ok, just been looking on Amazon and the battery connection lead and the light / charger for less than £15! Thanks so much for the suggestion!
At least I can check Boyer regulator for performance now before fitting the DVR2 when it arrives!
Thanks folks!
Title: Re: A10 misfire - tickover and lower gears
Post by: bsa-bill on 12.04. 2020 17:40
sounds like a neat bit of kit, but if it employs a led it will probably be polarity sensitive, you might want to try it the wrong way around (presuming your positive earth)
Title: Re: A10 misfire - tickover and lower gears
Post by: morris on 12.04. 2020 21:07
You don't need the optimate charger.
The  optimate charge controller connects straight to the battery poles so will always work, whether it's on + or - earth
I have a 2-pin SAE plug permanently connected to the battery to connect a trickle charger (Motobatt, comes standard with an SAE plug). The same plug can then also be used for the optimate charge controller/LED light. The negative pole from the battery is the negative output on the plug and thus gives correct polarity for the LEDs
Just be careful, if you have a positive earth as I have, not to touch the frame with the naked socket pin as that is the negative side! And don't forget to put the cap back on after use.
Title: Re: A10 misfire - tickover and lower gears
Post by: BSA_54A10 on 14.04. 2020 12:02
Similar idea used by us Morris.
We put a T shaped female plug on all of our batteries.
Then the male plug get fitted to replace the original battery wires.
The battery terminals are then painted over with liquid electrical tape .
So to charge you just pull the plug apart & plug in the charger .
Doing this prevents any corrosion at the battery terminals  and avoids confusion between + ground & - ground .