Suggestions for modern Starter Solenoid

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crusadersports

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Hello All,

Can anyone offer some suggestions for an up to date alternative to the Lucas Starter Solenoid on the MKIII?
I can find no helpful info in the manual or the Parts Book, by way of specifications. Mine is fine but I know they often fail so I was thinking of upgrading, if only as a spare.

Are all Solenoids the same? I expect not!

All serious suggestions (rather than 'Yes, chuck it off the nearest pier') very welcome :mrgreen: .

Thanks Gents :D
 
crusadersports said:
Can anyone offer some suggestions for an up to date alternative to the Lucas Starter Solenoid on the MKIII?
Click to expand...

If your MkIII has a Lucas solenoid-then it's not the original, as that would have been a Prestolite.


crusadersports said:
Are all Solenoids the same?
Click to expand...

Whatever solenoid you fitted, it would need a ballast resistor bypass connection if your MkIII still has points ignition? If its got electronic ignition, then a bypass wouldn't be required.
 
Sorry Les, you are of course correct. It does indeed have a Prestolite solenoid:D

I was hoping there was a modern alternative? I know it used to be suggested a Mini one was an improvement- in conjunction with, I think, a 4 brush conversion to the Prestolite starter motor. I imagine there must be an update on this by now....

Many thanks!
 
crusadersports said:
I was hoping there was a modern alternative? I know it used to be suggested a Mini one was an improvement- in conjunction with, I think, a 4 brush conversion to the Prestolite starter motor.
Click to expand...


Yes, the upgrade was to fit a Lucas solenoid in place of the Prestolite!

I don't think the solenoid type is particularly critical? Basically anything that fits should do, I think?

The 4-brush conversion does add a bit more power to the starter, but not as much as the 4-field coil conversion, however, with a good CCA battery, heavier gauge starter leads and only the 4 brush conversion kit, my MkIII's Prestolite starter turns the engine over quite easily.
 
Does anyone know what peak current the starter motor can pull?

If you want high reliability you need a hermetic contactor or solid state relay.
 
Thanks Rich and regards to deepest Surrey...

I'm no expert in these things but isn't a solenoid already a type of relay? I thought its purpose was to stop all the (250A-ish) going through the starter button? Are you saying the solenoid itself would benefit from some kind of additional relay, or the handlebar switches?

Les, yes I have a Boyer MKIII fitted. I have bought a Pazon after reading about the potential for kickbacks wrecking the sprag clutch. I thought the ballast resistor was fitted to allow 6v coils to be used instead of 12v (not sure why this is of benefit). Are you saying that with 'lecky ignition the ballast resistor is surplus to requirements?

Many thanks chaps for the input.
 
crusadersports said:
I have a Boyer MKIII fitted. I have bought a Pazon after reading about the potential for kickbacks wrecking the sprag clutch. I thought the ballast resistor was fitted to allow 6v coils to be used instead of 12v (not sure why this is of benefit). Are you saying that with 'lecky ignition the ballast resistor is surplus to requirements?
Click to expand...


The ballast resistor (or ballast bypass wire = 850 MkIII) must not be used with any electronic ignition system such as a Boyer, Tri-Spark Classic twin* or Pazon where the two 6V coils are connected in series.

*(A ballast resistor can be used with the Tri-Spark sequential firing ignition systems where 6V coils can be fitted in place of 12V, but not with the wasted spark 'Classic Twin' Tri-Spark system)
 
Thanks again Les,

Though still a wee bit confused. Mine has a ballast resistor, o/e 6v coils and Boyer.

Are you saying the ballast resistor should be by passed on the MKIII as standard (points), or just with 'lecky ignition? Without going out to the garage to check (bike is at my parent's), dare I ask what happens if the ballast resistor is not by passed with 'lecky ignition?

Many thanks
 
crusadersports said:
Though still a wee bit confused. Mine has a ballast resistor, o/e 6v coils and Boyer.
Click to expand...

Well, it can't be connected-or the Boyer ignition wouldn't (shouldn't) work?

Boyer fitting instructions: http://www.boyerbransden.com/pdf/KIT000 ... 00017_.pdf
12. Remove the white-blue wire from the ballast resistor between the two ignition coils.
Click to expand...
(Which effectively disconnects the ballast from the electrical system)

Pazon instructions: http://www.pazon.com/files/PDF/PA2.pdf
On the Norton Commando, remove the
white-blue wire from the ballast resistor between the two ignition coils; the
ballast resistor is no longer required.
Click to expand...
Same thing. With either system, the ballast is redundant so it can be completely removed.



crusadersports said:
Are you saying the ballast resistor should be by passed on the MKIII as standard (points), or just with 'lecky ignition?
Click to expand...

For the points system, the ballast bypass wire sends full battery voltage directly to the 6V coils from the solenoid-but only while the starter motor is turning (so only when the solenoid is energised) which temporarily boosts the coil voltage during electric starting.

http://britmoto.com/manuals/Manuals/850_man.pdf
Section J12

Electronic ignition works differently, the coils are wired in series and triggered by the box-so they are not directly connected to the electrical system, if the bypass wire was not disconnected then it would flood the coils with voltage while the starter motor operated, so the engine would turn over but it wouldn't start.
 
Greetings,
As L.A.B. said (sorta) anything that fits in there should work. Personally I'd go down to the local autoparts store and buy one of those old Ford type solenoids, the kind that used to set on top of the fender well near the battery. Used to be able to buy them for less than $10 and will certainly handle any current requirements your Norton will ever place on it.

GB
 
crusadersports said:
Thanks Rich and regards to deepest Surrey...

I'm no expert in these things but isn't a solenoid already a type of relay? I thought its purpose was to stop all the (250A-ish) going through the starter button? Are you saying the solenoid itself would benefit from some kind of additional relay, or the handlebar switches?

Les, yes I have a Boyer MKIII fitted. I have bought a Pazon after reading about the potential for kickbacks wrecking the sprag clutch. I thought the ballast resistor was fitted to allow 6v coils to be used instead of 12v (not sure why this is of benefit). Are you saying that with 'lecky ignition the ballast resistor is surplus to requirements?

Many thanks chaps for the input.
Click to expand...

Starter solenoid isn't actually a solenoid its a contactor (=relay).
If you go looking for starter solenoids you will find pretty much the same old agricultural thing as you have already, but if you know the current rating you need and go looking for relays/contactors of that rating you'll find a lot more stuff out there,. Because starters aren't used that much they don't need to have the same level of reliability as relays and contactors for general use but they are rated very high so you need to know what you're looking for.
There are a lot more products around now because of electric vehicles and traction motors.

Hence the question does anyone know the peak current draw for the starter motor or the current rating of the standard solenoid?
 
Ahhh, thanks Rich, that makes sense. I was thinking things must have moved on since the days of Prestolite.

The only info I can find in the manual says the solenoid draws (approx) 3 amps and the starter motor 'upto 250A depending on engine state and temperature'. This is from the table listing all the various electrical loads. There doesn't appear to be any proper specifications and only part numbers in the parts book.

Does that mean I am looking for a 250 amp relay to replace the solenoid then?

Many thanks
 
Rich_j said:
If you're serious about looking for reliability then this is the sort of thing you might want to look at

http://www.panasonic-electric-works.co.uk/catalogues/downloads/relays/ds_61213_en_ev.pdf

But make sure you're sitting down when you check the price :shock:
Click to expand...


Thanks Rich! Am I being dim (probably), but I can't see any prices in the pdf. Also, in the light of LAB's helpful info- that the oe solenoid has an 'intermittent duty rating of 100A', I am presuming that a 100 amp one of these will do? Why is a rating of 100 amps ok for the solenoid when the manual says the current draw for the starter motor can be 250amps?

LAB, thanks by the way, I have checked the ballast resisitor on mine and it is not connected. It was a wee while ago that I installed it and I've just left the resistor where it is- in case I ever want to go back to points :mrgreen:

Thanks for the input chaps!

Interested to hear from other folk who have uprated their MKIII starter solenoid to something more modern.
 
Cool, ok Rich, many thanks mate. Will look into it.

Have you tried any of these? Oh, and how does one actually measure the current draw for the starter motor?
 
Measuring the start current can be done a few ways but they all need some sort of special kit, if you know a friendly electrical engineer they could help out but most electricians are only kitted out in AC gear which is no good for this.

Best way of measuring is with a DC Clamp ammeter with peak hold function, alternatively a current clamp into a storage scope or high speed datalogger.
We have this sort of gear around at work maybe not so easy for yourself and others.

Sadly no electric boot on mine otherwise I'd take reading for you.

Just noticed you're also in blighty - try Googling that contactor part number, the UK price is buttock clenching.
 
The correct current draw for various configurations are on my webpage:
http://atlanticgreen.com/starter.htm
My data was in fact taken with a peak capturing meter on a 500A current meter I made.

FWIW the last time I checked, a solenoid IS a specific sub catagory of relay that has a moveable slug of metal internal to the coil. The actual technical performance details are probably not necessary.


added
practically all larger industrial contactors for motors etc are solenoids, with the moveable pole pieces internal to the coil.
But yes, the name is fading like capacitor over automotive ignition condenser.
 
dynodave said:
The correct current draw for various configurations are on my webpage:
http://atlanticgreen.com/starter.htm
My data was in fact taken with a peak capturing meter on a 500A current meter I made.

FWIW the last time I checked, a solenoid IS a specific sub catagory of relay that has a moveable slug of metal internal to the coil. The actual technical performance details are probably not necessary.
Click to expand...


Thanks for the current draw data.

You may be technically right about the term solenoid but its pretty archaic these days and AFAIK is only used in starter motor applications, probably because the machine at the heart of it has these days got shortened down to solenoid as well with obvious scope for confusion.
 
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