Author Topic: Plugs to points position  (Read 428 times)

Online Greybeard

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Plugs to points position
« on: 18.06. 2018 09:23 »
How do you know which spark plug relates to which points opening position?

Offline Sav

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Re: Plugs to points position
« Reply #1 on: 18.06. 2018 09:41 »
Get the wife to hold the end of one HT lead in one hand and the cylinder in the other whilst you give the kick start a prod.

After she has calmed down get her to check the other HT lead to make sure you are correct.
1961 A10SR, spent a fortune at SRM
1961 A7SS, finally the right green
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Online bsa-bill

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Re: Plugs to points position
« Reply #2 on: 18.06. 2018 09:50 »
you have to determine where the brass slug in the slipring thingy is in relation to the point thats is open then follow the pickup/plug lead, sorry you  probably know this already, I used know this and probably will again once I press "post", I think the bottom point on my Flash fires the drive side plug.
Pretty sure some one will enlighten both of us very soon (apart from sav that is)
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online Triton Thrasher

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Re: Plugs to points position
« Reply #3 on: 18.06. 2018 10:37 »
If the leads are each on the wrong plug, swap them over.


Offline duTch

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Re: Plugs to points position
« Reply #4 on: 18.06. 2018 10:54 »
 I think it depends which side is used for setting the timing....in my case when the points are at the bottom they do..umm *this*side, and when at the top, they do *that* side... *bright idea*

 ( weeelll -it started out ok.... *conf2* )
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online Greybeard

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Re: Plugs to points position
« Reply #5 on: 18.06. 2018 11:16 »
If the leads are each on the wrong plug, swap them over.
That's exactly what I had to do. My question was for a chap on Facebook. It would be a useful 'Sticky' for the forum.

Online groily

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Re: Plugs to points position
« Reply #6 on: 18.06. 2018 17:53 »
If you look at the contact breaker end, cover off  . . .
. . . . When the heel of the opening point goes onto the lower lobe, around 5 o'clock typically, it is firing the REAR pick-up of the mag - g'box side.
The lobe at 10 o'clock fires the front pick-up - engine side. 'Nearest to nearest' as it were.
So, if you do your set-up using the lower lobe, then the cyl that is on the compression stroke (both valves shut) is the one you hook up to the rear pick-up, g'box side.
Some people actually care which HT lead goes to which plug. I try to have the rear pick-up go to the RH cyl, but dunno why really!
Bill

Online Greybeard

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Re: Plugs to points position
« Reply #7 on: 18.06. 2018 18:19 »
If you look at the contact breaker end, cover off  . . .
. . . . When the heel of the opening point goes onto the lower lobe, around 5 o'clock typically, it is firing the REAR pick-up of the mag - g'box side.
The lobe at 10 o'clock fires the front pick-up - engine side. 'Nearest to nearest' as it were.
So, if you do your set-up using the lower lobe, then the cyl that is on the compression stroke (both valves shut) is the one you hook up to the rear pick-up, g'box side.
Some people actually care which HT lead goes to which plug. I try to have the rear pick-up go to the RH cyl, but dunno why really!

Thank you that's great! I hope you will not mind me copying and pasting some of that text into Facebook.

Admin, would you please make the original of this post Sticky as I'm sure many people will be searching for this information. Thanks.

Online groily

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Re: Plugs to points position
« Reply #8 on: 18.06. 2018 21:32 »
Don't mind at all GB.  Cheers - and hope remaining Qs about your valve train get sorted without your having to take anything apart again!
Bill