Dove oil valves

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Dove oil valves

Post by Mick D »

BruceB wrote:I am failing to see why I could not simply simplify the wiring by placing the oil switch as my original diagram and disable ignition by stopping the points being seen as open by the coil when closed
Hi

I think you can do exactly that - as long as you take the tapping from the line between the coil and the distributor and thus include the resistance of the coil.

In the OEM diagram the tapping is before the coil and would short the battery to earth without the restriction of the coil and thus risk overloading the wiring.

Regards Mick
Stan Palmer
Posts: 857
Joined: Tue May 27, 2008 2:19 pm
Location: SURREY UK

Re: Dove oil valves

Post by Stan Palmer »

Mick, it's shorted through the relay coil which is a small current.
Stan
Groily
Member
Posts: 2151
Joined: Thu Jul 04, 2002 1:00 am
Location: NORMANDIE FRANCE

Re: Dove oil valves

Post by Groily »

No disagreement from me on going your proposed simple route Bruce. As I said, I was quite happy doing exactly what you propose to do on my P11, until I 'back-graded' it to a magneto because I prefer them. Why would anyone not switch off the ignition anyway, it's the usual way to stop an engine!?

The wire to the dizzy supplies primary current to the live point at battery voltage and Yes, it does go to earth when the points are shut - but with ignition on & points closed there'll be approximately a 4A discharge through the coil at 6v, half that at 12v, until the battery is flat. Any current drain is unwelcome as it could lead to a flat battery and the AA Recovery Man - and a risk factor to some degree (although a fire is not at all likely, I do agree with Mick). But as the ignition isn't going be left on, it should be a non-issue!

The point remains though that makers of things really do have to consider what careless owners might do or forget to do, and try to make things fool-proof. It reminds me a bit of the problem with early Alton alternators, where the regulator adopted at that time tended to allow back leakage from the battery and a separate battery isolator switch was necessary rather than just desirable! . . . Solved now, but it created some adverse comments from owners. And a sexy gas barbecue I got not so long ago has so many fail-safe devices on it that I ditched the self-ignite facility in favour of long matches from Day One!
BruceB
Member
Posts: 95
Joined: Mon Dec 19, 2016 11:42 pm
Location: INVERNESS-SHIRE UK

Re: Dove oil valves

Post by BruceB »

I was a Railway Signalling engineer in the distant past so controls and failsafes are also a bit of a issue for me, however voting systems are not really used, it something fails anywhere the first option is everything goes to red!

However two points that seem to be confusing some folk that aren't really an issue.

On the original diagram the coil is seen by the voltage when the switch is on, there is no short and current only flows through the relay coil when the ignition is on. All I can see that the relay adds is a further failure point that is not even fail safe.

On the modified diagram the current will flow from the coil output with the switch closed to earth but since more than 80% of the time with ignition on this will happen through the points anyway I would not be worried about this. Leaving the ignition on is a bad thing anyway draining the battery If the ignition is left on normally without an oil switch it will drain the battery and do the coil little good. Remember that leaving the ignition on with the relay fitted and the oil switch on is exactly the same as a standard ignition system.

Neither way produces a dead short to earth in any circumstances, the relay version disables the complete ignition circuit and the simplified version simply puts a direct connection across the points to disable the spark when the points open.

I have emailed Kingpin to ask the same question, it just seems a more complicated ay than seems strictly necessary to achieve the same ends.
66 BSA Spitfire MK11
77 Yamaha XS750 Triple
98 Suzuki Bandit GSF600S
78 Honda Superdream (rebuilding)
51 Cyclemaster (in queue)
56 G11 bitsa (in boxes awaiting courage)
78 Series Landrover (rebuilding)
72 MG Midget (in queue)
06 Honda XL1000
BruceB
Member
Posts: 95
Joined: Mon Dec 19, 2016 11:42 pm
Location: INVERNESS-SHIRE UK

Re: Dove oil valves

Post by BruceB »

Kingpin did not reply to an email and there is no phone number on their website. However the valve is now in and wired and seems to work fine using the simplified wiring version. So much so that when I initially tried to start the bike and forgot to open the valve it was a good half dozen times before I remembered it was closed. A good reason to have it fitted in the first place, don't that a few times.
Had an interesting time trying to dynamically set the ignition timing, the electronic ignition can't be set manually as it has to be turning to produce a spark. What method has anybody tried for this, mine was a bit oily and messy with the timing cover off and marks on the drive gear, I have tried it with the chaincase cover of and this is just as messy. Can't think of any other way to get a timing gun on a running motor.
66 BSA Spitfire MK11
77 Yamaha XS750 Triple
98 Suzuki Bandit GSF600S
78 Honda Superdream (rebuilding)
51 Cyclemaster (in queue)
56 G11 bitsa (in boxes awaiting courage)
78 Series Landrover (rebuilding)
72 MG Midget (in queue)
06 Honda XL1000
ajsph
Member
Posts: 326
Joined: Mon Jan 01, 1990 12:00 am
Location: DENMARK

Re: Dove oil valves

Post by ajsph »

I made this tool for the timing gun.
Poul
20200619_145937_1.jpg
20190707_164049_1.jpg
20190707_164027_1.jpg
You do not have the required permissions to view the files attached to this post.
User avatar
robcurrie
Member
Posts: 957
Joined: Fri Dec 09, 2011 5:33 pm
Location: Limpopo SOUTH AFRICA
Contact:

Re: Dove oil valves

Post by robcurrie »

Very nice Poul, pity you only really need to use it once, but I guess you can rent it out to our club members. ;)

Rob C
User avatar
Taid
Posts: 710
Joined: Mon Oct 07, 2019 3:35 pm
Location: Shropshire UK

Re: Dove oil valves

Post by Taid »

I've fitted the Feked version to HSU, (wasn't aaware of the Dove tap until after I had bought from Feked) but because of the extra electrickery, including taking the magneto to earth, I've have the version for coil ignition.

It fits in nicely with the bike, but the problem is that it doesn't turn the electrics off until the tap is fully closed, (the switch is 'normally open') so that you can have the electrics working and able to run the engine with the tap almost turned off, thus blowing up the motor ..
Last edited by Taid on Thu Sep 03, 2020 4:46 pm, edited 1 time in total.
___

Now sold ... 1956 AJS 16MS Bitsa .. HSU 414 .. rebuilt/re-registered 1987
JEAN-NOEL
Member
Posts: 601
Joined: Wed Oct 12, 2005 10:45 pm
Location: FRANCE

Re: Dove oil valves

Post by JEAN-NOEL »

Hi Poul,
what a clever device ! I had thought of making a hole in the primary outer chaincase half to see the top dead center and full advance marks, static, or strobe. But it is not a reversible option...
User avatar
dave16mct
Member
Posts: 3234
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Dove oil valves

Post by dave16mct »

Jean-Noel, I had that arrangement on a 76 Bonneville. Its very messy with lots of oil flying about!
Dave.
Locked