Mk3 Electric Starter.

I am building a MK3 out of essentially spares and leftover bit and stuff I have accumulated over the years. I had a 4 pole prestolite motor from a harley modified to suit Norton. gathered all the info and gave to rebuilders .
When I picked it up they confirmed it had been bench tested and rotated correct way for norton etc.
I had completed the primary and hooked up a solenoid and battery etc and pressed the button and it just spun, in the wrong direction.so the sprag would not engage with the sprocket as reversed into free wheel mode.
I took motor off and tried to spin the gear train and could get no movement either way by hand.I had negative to solenoid and then to starter motor. positive to earthon engine crankcase...any clues before I start again. can I bench test starter to check polarity? do I need a solennoid to do it?
Thanks

No need for a solenoid to test but have the starter gripped well as it will jump with power applied. Don't have any flammable liquids around as sparks fly as you touch the final lead. Did you check the starter had not already been converted, if it had then it may now be back to where it started before the previous conversion.

I am pretty sure you can take the brushes out of their holders move them all ccw one holder over, and reinstall them. that will reverse the motor. Its fiddly for sure.

The really, really important bit in the OP is that the gear chain will not turn in any direction - strip the primary now, do not fit the motor until you have done so.
It is the the choice of a primary rebuild, or an expensive primary rebuild, and / or even trying to find a crank DS end.

johnny Lagdon said:

can I bench test starter to check polarity?

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If the starter motor polarity is reversed it will rotate in the same direction. To reverse the rotation the brushes must be moved as jimbo says.

Madnorton said:

The really, really important bit in the OP is that the gear chain will not turn in any direction - strip the primary now, do not fit the motor until you have done so.
It is the the choice of a primary rebuild, or an expensive primary rebuild, and / or even trying to find a crank DS end.

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I agree. It could be the anti-kickback device is slipping and needs to be tightened or replaced or the sprag clutch has broken the retaining ring. Make certain the sprag clutch is installed the correct way around.

Madnorton said:

The really, really important bit in the OP is that the gear chain will not turn in any direction - strip the primary now, do not fit the motor until you have done so.
It is the the choice of a primary rebuild, or an expensive primary rebuild, and / or even trying to find a crank DS end.

Click to expand...

Ron L said:

I agree. It could be the anti-kickback device is slipping and needs to be tightened or replaced or the sprag clutch has broken the retaining ring. Make certain the sprag clutch is installed the correct way around.

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The OP stated that when the motor was used the drive turned "in the wrong direction"........

johnny Lagdon said:

I had completed the primary and hooked up a solenoid and battery etc and pressed the button and it just spun, in the wrong direction.so the sprag would not engage with the sprocket as reversed into free wheel mode.

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....therefore unlikely the anti-backfire device would slip in that situation. If it did then the loud rattling noise the AB device makes as it does so would be unmistakable.

Jonny Lagdon
with the starter motor removed, you should be able to turn the large gear wheel (which fits inside the sprag) freely in a clockwise direction by hand.
It should lock as soon as you turn it anti clockwise, or the direction of normal engine rotation.
Both ops are easily checked by hand and correct rotation readily established.
If the gear wheel turns or locks in the opposite direction, you probably have the sprag fitted the wrong way around.

If it spins freely in both directions the sprag has flipped back the wrong way and needs replacing. I had this problem on a near new sprag in 2015 and took it back to AN who checked and replaced it straight away, the replacement lasting four years and over 10,000 miles with 100% e start on a healthy 850.

This should all be checked and tested by hand before finally fitting the starter motor. If the starter then spins in the wrong direction, that is a different problem and the brushes will needed to be rotated 90°

I have just fitted a new sprag, sprocket and chainwheel assembly along with a duplex primary using these exact proceedures. Worked freely by hand in the right direction and fired up perfectly with starter motor fitted.
I set the timing at 28° using the crankcase slot on the lower right side under the ignition cover for accuracy rather than the primary case indicator. Trispark ignition and Boyer Micro Digital Power backfire free with this method.

Old Britts have an excellent article on e start assembly, saved me much time over the years bless them, and there is also a link on adjusting the backfire device:
https://www.oldbritts.com/e_start_gears.html

Thanks for all replies.
I am going to strip the starter gear train again as with starter and idler removed, i should be able to move the gears by hand as spragg should not be engaging.
Sprag is brand new 18tooth, and worked perfectly when i tried before fitting sprocket and large inner gear. spun one way but not other as it should.
if no success will get stater brush position double checked.

I removed the stator, rotor and no change. Loosened the outrigger plate the stator mounts on man suddenly everything was as it should be, reverse the large gear on the spragg and sprocket. nipped it up but not to full tight and started to get harder to move.
further examination required.

after much trial and error it is the stator mounting plate causing the jamming problem. after repeated tightening and finessing of all bits, the plate is a little warped, and this was putting a side load on the backfire overload shaft that mounts in it as well. Now for the starter motor.

johnny Lagdon said:

after much trial and error it is the stator mounting plate causing the jamming problem. after repeated tightening and finessing of all bits, the plate is a little warped, and this was putting a side load on the backfire overload shaft that mounts in it as well. Now for the starter motor.

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Another member had what seems to be a similar problem recently.
https://www.accessnorton.com/NortonCommando/mk-3es-outrigger-plate-problem.26798/#post-403568

for the new uprated starter motor from Norvil : it spins SAME way for either polarity of connection. Useful as I changed to negative earth!

problem solved with new outrigger plate that wasnt warped

jan nelder said:

for the new uprated starter motor from Norvil : it spins SAME way for either polarity of connection. Useful as I changed to negative earth!

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See LAB's correction

I have in place an 18 tooth made in China sprag that cost $17 on AliExpress.
When I bought the bike 15 years ago the sprag was slipping so I replaced it with a 14 tooth $150 Norvil item. That sprag lasted 2 days, no warranty from Norvil.
So I gave up on the estart and used kickstart, it is a very easy starter ( Boyer and twin Amals)
The knee started acting up awhile ago so it made sense to reactivate the estart.
Matt at CNW posted that he planned to offer uprated MK3 estart drive parts, so I waited awhile for those.
The knee was getting progressively worse (1360 Vincent!) so I thought the 17$ Chinese sprag was worth a gamble until the CNW parts become available.
The $17 sprag has been in use almost 3 years now, about 200 starts and works a treat. I do have a tiny second battery in place that is isolated to provide full ignition voltage to the old Boyer on cold startup. More modern EI setups probably wouldn't need this.
This starter has the four pole conversion and heavier supply wires added.

Glen

kommando said:

the prestolite has field coils which use battery voltage to create the magnetic field, reverse your connections and it will spin backwards.

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I can assure you it doesn't.

kommando said:

The other flavour is PM or permanent magnet which use magnets with no connection to the battery, reverse the connections on these and their spin direction is unchanged. The only way to reverse the PM type is to index the bushes 90 degrees.

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It's the field coil type that need the brushes moved to reverse.

Edit: https://www.quora.com/What-will-be-...-motor-if-the-supply-terminals-are-reversed-1

worntorn said:

I have in place an 18 tooth made in China sprag that cost $17 on AliExpress.
When I bought the bike 15 years ago the sprag was slipping so I replaced it with a 14 tooth $150 Norvil item. That sprag lasted 2 days, no warranty from Norvil.
So I gave up on the estart and used kickstart, it is a very easy starter ( Boyer and twin Amals)
The knee started acting up awhile ago so it made sense to reactivate the estart.
Matt at CNW posted that he planned to offer uprated MK3 estart drive parts, so I waited awhile for those.
The knee was getting progressively worse (1360 Vincent!) so I thought the 17$ Chinese sprag was worth a gamble until the CNW parts become available.
The $17 sprag has been in use almost 3 years now, about 200 starts and works a treat. I do have a tiny second battery in place that is isolated to provide full ignition voltage to the old Boyer on cold startup. More modern EI setups probably wouldn't need this.
This starter has the four pole conversion and heavier supply wires added.

Glen

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FYI, Years ago I replaced my sprag bearing and greased it up real good, it wouldn't grab at all . I had to clean the grease out of it for it to grab as needed.

I can imagine the sprag would slip when coated with grease. It's kind of amazing that they grip at all in oil of any type.
The slipping sprag had type f ATF in place, which is about as grippy as lube can be. The cage was broken, that was the problem there.
The Norvil sprag gripped nicely but it also broke it's cage and did so rather quickly after install. Then it jammed things solid.
I had to call for tools then do a roadside removal of the sprag.
After that experience I fully expected the Chinese sprag to break up on the first day.
It has exceeded my expectations by about 9,000 % so far!

Glen

worntorn said:

I have in place an 18 tooth made in China sprag that cost $17 on AliExpress.
When I bought the bike 15 years ago the sprag was slipping so I replaced it with a 14 tooth $150 Norvil item. That sprag lasted 2 days, no warranty from Norvil.
So I gave up on the estart and used kickstart, it is a very easy starter ( Boyer and twin Amals)
The knee started acting up awhile ago so it made sense to reactivate the estart.
Matt at CNW posted that he planned to offer uprated MK3 estart drive parts, so I waited awhile for those.
The knee was getting progressively worse (1360 Vincent!) so I thought the 17$ Chinese sprag was worth a gamble until the CNW parts become available.
The $17 sprag has been in use almost 3 years now, about 200 starts and works a treat. I do have a tiny second battery in place that is isolated to provide full ignition voltage to the old Boyer on cold startup. More modern EI setups probably wouldn't need this.
This starter has the four pole conversion and heavier supply wires added.

Glen

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Would you still have available the Aliexpress sellers details ?
Thanks
Paul