Ignition Timing on my 1960 A7SS

[BSA Biker]

 After getting back my completely rebuilt magneto from Draganfly in early December and at the same time changing the pistons to the standard 7.25:1 comp. My bike started very quickly and ran for a few minutes, before I turned it off to re-adjust the tappets following the settling down of the gaskets, when cold.

The timing also needed adjusting so that was done at the same time, 3/8" BTDC as shown in the manual, but try as I might it will not start now, either by having it too far advanced or too far retarded, never had this problem before and it rather annoying having tried to re-adjust it 3 or 4 times without it starting, what on earth am I doing wrong?. There is a good spark at the plugs, on one occasion it was banging in the pipes showing that it was firing after TDC, another time it would kick back a lot, firing before TDC, oh to get it right. Yes the gap is correct at 10thou, and 2thou for setting.

On another tack, does anyone know about the new Iridium tip plugs, are they worth using and what one would be best for my bike, in the old days I used KLG FE80, the strip down type, had to go to Japanese ones years ago. Unfortunately living in Spain out in the wilds, I've lost track of "modern Technology".

[Billybream]

Try swopping the HT leads over.

[muskrat]

G'day BB.
Check Billy's suggestion. Easy to mix'em up.
Making sure that it's set at full advance (slack cable) I use a half a timber cloths peg wedged against the post and cam ring to hold it while i gently put the pinion on then give it a tap to seat it.
3/8" btdc (38 degrees) might be a bit much with today's fuel (unless your using 98+) 5/16 may work better.
One of my pet hates is the "stick down the plug hole and fag paper in the points", might be OK on the side of the road and most still do it that way. I drop the primary cover off and put a degree wheel behind the cush nut and strobe test the timing on both sides.
Cheers

[KiwiGF]

Agree with swapping leads over, on plug choice.

The general advice is to use a plug (and caps) without resistors in when using a std magneto (as opposed to electronic ignition). This limits plug choice!

The swapping of plug leads over works because there is no “spare” spark on a10s. So the correct lead has to be on the correct plug. You can check this for certain by putting the engine at TDC and seeing which slip ring copper is showing in the mag lead hole, that lead should be going to the cylinder with the valves shut.

[JulianS]

I used Denso IW22 iridium resistor plugs on my A10 for several years. My impression was that the bike pulled a bit better and burnt a bit cleaner. The negative side was first the high price and second that the life was fairly limited before plug failure. Presume they did not really like the magneto. This persuaded me to stop using them and go to Denso W22ES non resistor plugs.

Tried NGK iridium BR7EIX resistor plugs but the bike did not run as well on these.

[Rgs-Bill]

Agree with swapping leads over, on plug choice.

The general advice is to use a plug (and caps) without resistors in when using a std magneto (as opposed to electronic ignition). This limits plug choice!

The swapping of plug leads over works because there is no “spare” spark on a10s. So the correct lead has to be on the correct plug. You can check this for certain by putting the engine at TDC and seeing which slip ring copper is showing in the mag lead hole, that lead should be going to the cylinder with the valves shut.

     Magneto Ignitions do not like resistor plugs at all, besides being harder to start, the resistance may build up more heat in the fine wire windings, which is never good.
   I have had best luck with Bosch first, Champion second in a heat range 1 to 2 hotter, than the NGK B-8-ES because of the crummy ETHONOL FUEL we have to live with now a days.  I also have a newly re-wound, and new bullet proof condenser in my maggy, so starting gap before timing is .013 , and my plug gap is at .035, seems to burn the fuel charge more completely.  My 2 cents worth is all, to each his own way ! ! ! !

[muskrat]

Bill's right, no resistors plug/cap/lead (carbon leads) for our magies. As far as I know all Iridium plugs are resisted. If you want to go fancy try NGK B7EGV. I used them when racing the A7SS but in the 9 heat range (burning methanol).
Cheers

[Black Sheep]

I've used B7ES for years. Fit and forget. Plug gap 0.018". You don't want resistor plugs or resistor plug caps either. Bad for magnetos...

[JulianS]

The post 1953 UK market bikes would have been fitted with suppressed plug caps as a legal requirement when new so the mass produced mags from then were able to cope with such. No doubt our recent artisan rebuilt mags with improved materials  deal with resistors/suppressors equally well or better than the originals.

But as always the choice is ours!

[bsa-bill]

The post 1953 UK market bikes would have been fitted with suppressed plug caps as a legal requirement when new

I'm not sure about that, my Flash was 1961 pre owned for only one year by a guy known for his care of vehicles and I don't recall suppressor plug caps at all, but it was a while ago.

[bikerbob]

I think Julian is right about the suppressed plug caps I believe it was a legal requirement back then and I seem to remember that the reason for the legal requirement was something to do with television interference.

[bsa-bill]

Yes I recall people fitting capacitors to car radio's, but much later then 51, The plug caps Draganfly list  are non resister and I think look like the ones I recall, but as said it was along time ago

[Black Sheep]

Yes, suppressor caps were indeed a legal requirement in the UK. You could tell an unsuppressed vehicle driving past by the crackle on your radio or TV. Now that we have gone electronic and digital, there is not the same requirement. Unsuppressed caps are kinder to magnetos though, as mentioned, mags do cope.

[Triton Thrasher]

G'day BB.
Check Billy's suggestion. Easy to mix'em up.

Even if BSABiker hasn’t mixed the HT leads up, he may have timed a cylinder to the other cylinder’s points cam ramp.

[BSA Biker]

Actually I hadn't got the points set at the right place. Finally got it nearer today and it started, but will need to do it again to get it dead right. Back in the summer I purchased a new timing ring from SRM in wales, this is great for the correct points gap in both places, but it is a real bitch to get the 2thou setting right as the ramp is all or nothing. Hence my problems, must have been lucky first time I set it. Yes I use the right hand piston to time it, as stated 3/8" BTDC' I use non ethanol petrol at about 97octane?.

When the bike was younger the plug caps were Lucas black bakelite suppressor type, older bikes used to effect the telly or radio if not fitted, as stated by others, I changed to unsuppressed ones many years ago. As for the swopping over of the HT leads that is not possible as mine are cut to the correct length and will not fit the other way round. Its just me not getting it right.  Thanks for the info. I use NGK B8ES plugs, won't bother to change to the newer Iridium ones.