750SF Starter Motor

Lost count of how many of these I've brought back from the dead. The main culprit has always been carbon residue mixed with oil/grease, coating the brushes and visible parts of the armature, paired with worn brushes.

Armatures do give up should the clutch jam while the engine is running, they weren't designed to spin at 20000rpm. In such a case, there's not much to salvage other than the nut holding on the power supply. Other than that, unsalvagable burnt commutators are pretty rare and I have yet to find burnt field windings. As I've stated, the things are pretty damn bulletproof.

The starter in the video certainly is tired, a thorough going-through of the starter and associated components should get it going again pretty well. I don't see any smoke and as it's still turning, the internals aren't yet totally fucked...

piet
 
sfcpiet said:
Lost count of how many of these I've brought back from the dead. The main culprit has always been carbon residue mixed with oil/grease, coating the brushes and visible parts of the armature, paired with worn brushes.

Armatures do give up should the clutch jam while the engine is running, they weren't designed to spin at 20000rpm. In such a case, there's not much to salvage other than the nut holding on the power supply. Other than that, unsalvagable burnt commutators are pretty rare and I have yet to find burnt field windings. As I've stated, the things are pretty damn bulletproof.

The starter in the video certainly is tired, a thorough going-through of the starter and associated components should get it going again pretty well. I don't see any smoke and as it's still turning, the internals aren't yet totally fucked...

piet
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😂😂 nothing better than waiting for the total fucked moment to arrive 👍👍
 
sfcpiet said:
Lost count of how many of these I've brought back from the dead. The main culprit has always been carbon residue mixed with oil/grease, coating the brushes and visible parts of the armature, paired with worn brushes.

Armatures do give up should the clutch jam while the engine is running, they weren't designed to spin at 20000rpm. In such a case, there's not much to salvage other than the nut holding on the power supply. Other than that, unsalvagable burnt commutators are pretty rare and I have yet to find burnt field windings. As I've stated, the things are pretty damn bulletproof.

The starter in the video certainly is tired, a thorough going-through of the starter and associated components should get it going again pretty well. I don't see any smoke and as it's still turning, the internals aren't yet totally fucked...

piet
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But you can also post to the UK.
Paul
 
Paul Marx said:
But you can also post to the UK.
Paul
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I'll bother the Kings' couriers when I'm at my wits' end Paul. Until then, I'll just carry on... ;)

Mel said:
😂😂 nothing better than waiting for the total fucked moment to arrive 👍👍
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Well, the OP is asking if it's normal what he is experiencing. At the very least, it has occurred to him it may not be normal, that's a lot better than to unknowingly shag it completely.

Many Laverda newbies are told "They all do that...", there are far too many experts bullshitters out there. As those who have persevered with these bikes have largely found out, there are a lot of quirks surrounding them, they are not to be mistaken with a UJM.

piet
 
sfcpiet said:
I'll bother the Kings' couriers when I'm at my wits' end Paul. Until then, I'll just carry on... ;)


Well, the OP is asking if it's normal what he is experiencing. At the very least, it has occurred to him it may not be normal, that's a lot better than to unknowingly shag it completely.

Many Laverda newbies are told "They all do that...", there are far too many experts bullshitters out there. As those who have persevered with these bikes have largely found out, there are a lot of quirks surrounding them, they are not to be mistaken with a UJM.

piet
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Certainly plenty of quirks about Laverdas , Not a clue what a ujm . But it sounds painful 🙂
 
sfcpiet said:
Unless they have been seriously neglected/abused for many years, the ND starters are pretty bulletproof. A general internal clean-up, a skim over the commutator and new brushes usually brings them back to top working condition. No rocket science involved.

The starter clutch requires periodic servicing, which mostly includes a new set of springs. If not attended to, a faulty clutch will gradually self-destruct.

I can supply NOS brushes if required.

piet
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Hi Piet!
Do you still have the induction coil set that you sold me once? The four coils that are fixed screwed to the starter body… i have a few old starters that I would like to overhaul.
Regards
Miguel
 
I rebuild a few of them as well, even painting with cerakote both the body, the brush plate and all corroded parts, result was great and working perfectly. As Piet say, no rocket science, but need to have clear the current flow and ensure that negative is reaching the engine and that the positive is well isolated… the first time you connect the cable after such a rebuild it takes 2-3 seconds until it starts spinning, probably creating some magnetism stuff🤪🤯 very long 2 seconds🤣
 
OTR002 said:
I've replaced all the battery/solenoid/starter leads and connections with new, although I haven't checked the starter solenoid itself.
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Go with Piet’s advice, careful disassembly, clean and reassemble. Post photos and we’ll critique your work 🤣
Solenoid is definitely worth a check. Or replace with a basic car one. And add the sprag clutch to your regular maintenance schedule 👍
 
michipons said:
I rebuild a few of them as well, even painting with cerakote both the body, the brush plate and all corroded parts, result was great and working perfectly. As Piet say, no rocket science, but need to have clear the current flow and ensure that negative is reaching the engine and that the positive is well isolated… the first time you connect the cable after such a rebuild it takes 2-3 seconds until it starts spinning, probably creating some magnetism stuff🤪🤯 very long 2 seconds🤣
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Absolutely agree with ensuring the cables and connections are good. And I remember your photos of your renovated starter, very nice 👌But the delay you mention is not good…
 
Andy said:
Absolutely agree with ensuring the cables and connections are good. And I remember your photos of your renovated starter, very nice 👌But the delay you mention is not good…
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This delay happened only for the first time, it happened in every starter I rebuilt, 🤷🏼‍♂️. But from them, always smooth, for a few years already
 
Mel said:
Certainly plenty of quirks about Laverdas , Not a clue what a ujm . But it sounds painful 🙂
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Haven't worked on any car. mower, bicycle, wheelbarrow ... that doesn't have quirks. Sounds like you've had bad luck with the usual problem-solving of owning a vehicle. BTW, UJM = Ubiquitous Japanese Motorcycle.
 
Fix it, I once spent a week on holidays in Melbourne OZ 1000ks from home bump starting my 3c with luggage on it. Not fun. When back I had the now long gone ancient Auto Electricians, a family firm around in the same building since the 1920s rebuild my starter, and a couple of weeks later more issues with the starter relay, it was also stripped and rebuilt. Or at least they filed its contacts clean. Love those YE-OLD SCHOOL FIRMS back then. Sadly now all dead and buried.
 
piranha-bro2 said:
Haven't worked on any car. mower, bicycle, wheelbarrow ... that doesn't have quirks. Sounds like you've had bad luck with the usual problem-solving of owning a vehicle. BTW, UJM = Ubiquitous Japanese Motorcycle.
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Bad luck , no such thing . Just things that happen and we have to sort them out . Cheers for the clue about ujm thou , it did sound painful and it is 😂😂
 
Speaking of starter motors and clutches, I was stranded by a starter malfunction for the first time in 50 years of SF ownership this arvo. First ride since new piston, straight to the local servo to fill up. go to leave, hit the starter button ... 'whiiiiiiizzzzz! I start cursing you, Piet, cos it sounds like my brand new starter clutch has carked it on its first outing!
Tried push starting down a slight downhill side street - 3rd gear, 4th gear, no chance. Just can't get it to offer more than two compressions before the rear wheel locks up.

Call the help to come and pick me up, come back with all the tools required for starter clutch rebuild at the side of the road, pull the cover, freewheel is loose, key broken and spinning beautifully on the crank!! Sorry Piet!! Never had one come loose before. Cleaned up the mating surfaces with brake cleaner and whacked it back on without the key and did the nut of nicely tight and ... vroom! Bewdiful. Back home, ride the bicycle back to get the car. Been a long day.

I'll give it a light grind with valve paste and make a new key before the next big ride. Prob is, how long has the key been busted and the freewheel turning on the crank??? Because that's what I bolt my degree wheel to and set ignition timing with!! Should still be set correctly, becasue I didn't start the motor until base adv had been set. But back to the piston stop, base advance procedure once again!! Might explain why I saw 50 deg advance a couple of times on the strobe!!! :eek:
 
Broke a key on a Husky 2 stoke once, it did more than not start. Thought I had broken my leg with the kickback.
 
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