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Eurocycleguy

Eurocycleguy

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Chicagoland-USA
Working/learning on rebuilding Starter Clutch for 750. Clutch action is better only occasional catches, crunches and sparks flying out of clutch.
AND Then apparently the engine didn't start but the Starter Motor kept turning over and the Starter Clutch was engaged. Bang on starter Button, Pull Key out, $h!t gotten get the seat off! Wait get side panel off get to Solenoid! Crips! cable smoking
Undo nut on output terminal of solenoid $h!t that's hot!
So starter Clutch is still not right after rebuild with new parts Spring, Pegs (Plungers), Rollers all nicely lubed and riveted back together. Still chunks, clunks and spits sparks :mad:
And now I get to delve into the mysteries of the solenoid, not hard I know just another item on the list. Grrrrrrrrrrr
Rant done for now. (y) All Better. 😇
 
OEM solenoids ( Bosch ) were a problem, in the day. Not so much welded contacts though, careful routing of cables to the terminals also a "care" point, ie insulated covering of any electrical metal parts. Given having parts from crashed Kwaka ZZR/GPX 250's i retrieved the excellent solenoids and on board fusing feature.

Odd to have heat damage all the same, save for a high resistance crimp or loose terminal, at least you can now renew the starter wiring, with conviction. FWIW, i use welding cable ( 16m/m from failing memory ) crimped with proper lugs and tools, need care with welding cable as being fine strands, it does not compress like usual grade wire, ie need a very tight fitting lug to begin with. Possibly a local electrical wholesaler can assist with cable, lugs and proper tooling. Your only paying for this over say 10 years and can accepted as wise money spent. j
 
To put it bluntly, it's worn out.

The race on the sprocket wears, the ramps on the internal ring wear. Once these are too far worn, there's too much space for the rollers and they either cannot engage properly or jam at the very end of their travel and cannot "unlock" once the engine starts. Or the internal ring has cracked up, symptoms are much the same.

Source a better sprocket and internal ring and re-build. Internals are all available, sprockets are a different matter.

Molten solenoid/relay is a side effect of needing to hold the start button too long to get things moving.

These bikes, actually all bikes, were not meant to eventually be 50 years-old. Even Massimo wanted us to buy a new bike every 4-5 years.

piet
 
Lucky it was only the starter driving the clutch, because if the clutch seizes you spin your starter at say 4 or 5 times engine speed!! Hope it all checks out for you.

Sounds like the solenoid seized due to dodgy connections and excessive heat, or simply old age and degraded internal solenoid contacts - as Piet and John have already said. Can be very expensive when it all gos wrong.
 
Is you battery fully charged and in good condition? If not when you press the starter button it will not get up to speed fast enough to push the rollers in and grab the inner ring. I worked on a 750GT that even with all new stater clutch parts would not work properly. The battery seemed OK but putting a new one in the bike fixed all the starter clutch problems.
 
the original item from Bosch for triggering the starter current at the starter motor is not a solenoid, its a relay rated at 80 amps and sold by dealers for far too much money, use a solenoid (yes a proper solenoid) from a land Rover, Mini, Jaguar Austin etc, obtained from any local car shop for about 15GBP. The rated current passage is more like 450amps, they last about 20 years in Lav service (my experiance) and are (obviously) cheap to replace, they have the added advantage of a few extra 12v LT male spade terminals for use on varius appliances, one is "live" only when cranking, so is (on the cars) used for a direct 12v+ boost to the coils, on the 180 Lavs they run at 9V after the resistors, so this can be wired for a voltage boost when starting, (and retain the reswistors for ultra long coil life) another is permanently live and the last one live only when the ignition is on, great for sat navs.
CLEM
 
Wow LOTS of good info and experience here. Thank you.
What is currently (see what I did there?) on the bike is a used Bosch of unknown lineage. I have the original Bosch from when the bike was set on fire; at that time the bike only had 7K miles on it. I replaced it because of it's cosmetic reason, burnt on soot.
Before reading these replies I thought I would open up the original relay, inspect and attend to what needed attention. Ideally I would like to keep the bike as original as possible. But now I am reconsidering, and thinking I should just "modernize" with new components, wiring and cables. When I am confident of the starter system then I will go back to the Starter Clutch ca-chunking, catching , releasing, spitting sparks.
 
iis_iis said:
OEM solenoids ( Bosch ) were a problem, in the day. Not so much welded contacts though, careful routing of cables to the terminals also a "care" point, ie insulated covering of any electrical metal parts. Given having parts from crashed Kwaka ZZR/GPX 250's i retrieved the excellent solenoids and on board fusing feature.

Odd to have heat damage all the same, save for a high resistance crimp or loose terminal, at least you can now renew the starter wiring, with conviction. FWIW, i use welding cable ( 16m/m from failing memory ) crimped with proper lugs and tools, need care with welding cable as being fine strands, it does not compress like usual grade wire, ie need a very tight fitting lug to begin with. Possibly a local electrical wholesaler can assist with cable, lugs and proper tooling. Your only paying for this over say 10 years and can accepted as wise money spent. j
Click to expand...
Yeah I have been using original Cables. I will replace them. Thinking about another brand new different manufacturer solenoid. Besides crimping I would consider soldering; probably melt some of the original sheathing at lug. I would have shrink tubing in place read to cover excess heat bo-bo.
thank you iis_iis for your thoughts
 
Last edited:
sfcpiet said:
To put it bluntly, it's worn out.

The race on the sprocket wears, the ramps on the internal ring wear. Once these are too far worn, there's too much space for the rollers and they either cannot engage properly or jam at the very end of their travel and cannot "unlock" once the engine starts. Or the internal ring has cracked up, symptoms are much the same.

Source a better sprocket and internal ring and re-build. Internals are all available, sprockets are a different matter.

Molten solenoid/relay is a side effect of needing to hold the start button too long to get things moving.

These bikes, actually all bikes, were not meant to eventually be 50 years-old. Even Massimo wanted us to buy a new bike every 4-5 years.

piet
Click to expand...
Hello sfcpiet, Maybe it is worn out but it sure looks good to me. Sprocket race looks great, nice and smooth and shiny. No flat areas, no visible or touchable defects. Internal ramps look good. I had this "clutch" completely apart. Cleaned inspected, replaced all internal bits (springs, pegs, rollers) (old ones looked fine as well). Internal ring: no cracks or shiny worn spots all nice and blue/black. These parts only had less than 11K miles on them. (Shame on me for not using it enough) Bike had 7K from original owner, I bought it in 2000 and let it sit for 15 or so years, only got it together and running 5 years ago.
Yeah creeping up on 50, gotta give it more attention the poor old geriatric.
As for the new bike buying strategy I've been doing that with Beemers, 5+ in the last 18 years.
 
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piranha-bro2 said:
Lucky it was only the starter driving the clutch, because if the clutch seizes you spin your starter at say 4 or 5 times engine speed!! Hope it all checks out for you.

Sounds like the solenoid seized due to dodgy connections and excessive heat, or simply old age and degraded internal solenoid contacts - as Piet and John have already said. Can be very expensive when it all gos wrong.
Click to expand...
Yeah as soon as the it kept turning I thought of exploding starter motors. I have one that came with the second Lav I bought. Scared me big time. But I was watching it turn over and thinking how is the engine running this slowly? I thought (assumed) the engine had started and clutch is still engaged. I got stop this before the starter motor explodes. hit starter button, pulled ign key out, put key in, turned key off on pulled out, pulled spark plug caps off, started to take seat off to get to battery, Stopped engine and all this action by putting bike in gear. (bike is on lift with front wheel in wheel vise) stopped, took sidecover off, cut trigger wire to relay, got wrenches and removed cab from relay to starter- very hot. then all was quiet except my heartbeat. Than you piranha-bro2
 
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1200ts said:
Is you battery fully charged and in good condition? If not when you press the starter button it will not get up to speed fast enough to push the rollers in and grab the inner ring. I worked on a 750GT that even with all new stater clutch parts would not work properly. The battery seemed OK but putting a new one in the bike fixed all the starter clutch problems.
Click to expand...
I don't know the battery condition, it is relatively new, maybe not now that I think of it, 4 years. I charge it every 4-6 months if I am not riding. I will look into Batt situation after I deal with the relay, wiring and cables. Thanx 1200ts
 
CLEMTOG said:
the original item from Bosch for triggering the starter current at the starter motor is not a solenoid, its a relay rated at 80 amps and sold by dealers for far too much money, use a solenoid (yes a proper solenoid) from a land Rover, Mini, Jaguar Austin etc, obtained from any local car shop for about 15GBP. The rated current passage is more like 450amps, they last about 20 years in Lav service (my experiance) and are (obviously) cheap to replace, they have the added advantage of a few extra 12v LT male spade terminals for use on varius appliances, one is "live" only when cranking, so is (on the cars) used for a direct 12v+ boost to the coils, on the 180 Lavs they run at 9V after the resistors, so this can be wired for a voltage boost when starting, (and retain the reswistors for ultra long coil life) another is permanently live and the last one live only when the ignition is on, great for sat navs.
CLEM
Click to expand...
Hi Clem, Thanks for your earlier advice on the Starter Clutch. I would like to retain an original BOSCH Relay if possible I have two to inspect and work with. BUT I have already considered an automotive replacement. Here in the "Land of the Free" NOTHING is 15GBP, especially them there furin cars Land Rover, Mini, Jaguar Austin etc. I am not running any extra accessories on this GT that would need the switched or ignition live power. I have a Pazon ignition installed on this bike. and previous to COVID lockdown when I would start the bike, literally touch the start button and it was running. Now not so.
 
Have you measured the relative diameters? i.e. freewheel contact ring vs. distance between opposite rollers at each end of the ramps. That will help to establish the state of wear, and there isn’t a lot to play with.
There has been some discussion on here previously about using incorrect rollers either by accident or to overcome wear, not sure the outcome but perhaps you have odd rollers?
P.S. lots of first-hand experience can be found on here by searching “sprag” with “sfcpiet” 👍
 
Hey Andy, No I have not measured and compared the diameters between the bearing surface and between opposite rollers.
The bike has sat for 2+ years and it engaged and started fine before that hiatus.
I have two sets of the Sprockets w/ bearings and Starter Clutches. The set that is off the bike The bearing fits amongst the Rollers fine by moving the rollers back a bit which allows the bearing to nest in the Clutch.
By hand the one way locking action works great.
I realize I need to remove the on bike Clutch to check it out, and I will tomorrow or Monday. The wifey is leaving Tuesday for a long trip and I am going to be out of the garage a bit more.
Maybe installing the Clutch on the bike I am dislocating a Roller or two and this is causing the issue????? :unsure:
 
Original parts on these older Laverda's a worthy cause, can well understand the impetus. Numbers game, when is a part past its service life. Can it be made like new again by repair of internal or external workings. When on a domestic electronics service bench, my comment to customer on return or working VCR, "it is now not new again, it has a new part, not a whole new VCR". Starter solenoid, can be made to operate as designed by clean and retension the various spring parts, yet heat damage will reduce spring tension abilities. Lets say you get a opening contact arc across the high current contacts, if lucky the slow opening contacts will weld by electric arc. Some 200-400amps of stalled or locked rotor/armature current, measured up to 600 using special equipment.

There are places to hide any new more reliable devices on the Laverda, a notable as i designed the hardware for the iis was to "hide" the microprocessor based ignition. Elaborate crankshaft encoder is well hidden, the ignition module, can be behind a battery which is behind a side cover. As the owner and rider, you make decisions about reliability. Stuck out in the sticks, 3 hours from home, makes many decisions very clear, let alone a $600 pickup bill to get bike back to home..... pestering your mates to get a trailer and return.... Another aspect i use, save money on various items, spend lots on suspension, brakes and tyres, comfort is not a luxury, needs to be made best of. Tah for the personal addressed replies, nice j.
 
It has been discussed many times, but don't solder wires on a LAV unless it is the only way to make a connection such as in a handlebar switchblock. large number of technical reasons which I shall not repeat, but as John states, being 3 hours from home ......

You should be able to get the larger starter motor cable crimped to suit by an auto electrician, even in the 'land of the free'. probably make up exactly what you want.
Here is AUS, auto electricans are a dying species, on the endangered species list.

As has been stated, if using the original or new starter relays/solenoids, it is good practise to heat shrink over the termination once tightened, and proven to work properly. Just the normal heat shrink. I would not recommend the one with internal 'glue'.
Generally there is not much space between terminals on these devices.

Remember, Murphy is alive and well. and just LUVS old motorcycles.
Good luck.
 
iis_iis said:
Original parts on these older Laverda's a worthy cause, can well understand the impetus. Numbers game, when is a part past its service life. Can it be made like new again by repair of internal or external workings. When on a domestic electronics service bench, my comment to customer on return or working VCR, "it is now not new again, it has a new part, not a whole new VCR". Starter solenoid, can be made to operate as designed by clean and retension the various spring parts, yet heat damage will reduce spring tension abilities. Lets say you get a opening contact arc across the high current contacts, if lucky the slow opening contacts will weld by electric arc. Some 200-400amps of stalled or locked rotor/armature current, measured up to 600 using special equipment.

There are places to hide any new more reliable devices on the Laverda, a notable as i designed the hardware for the iis was to "hide" the microprocessor based ignition. Elaborate crankshaft encoder is well hidden, the ignition module, can be behind a battery which is behind a side cover. As the owner and rider, you make decisions about reliability. Stuck out in the sticks, 3 hours from home, makes many decisions very clear, let alone a $600 pickup bill to get bike back to home..... pestering your mates to get a trailer and return.... Another aspect i use, save money on various items, spend lots on suspension, brakes and tyres, comfort is not a luxury, needs to be made best of. Tah for the personal addressed replies, nice j.
Click to expand...
Hello j, When I disassembled the Starter Relay I did not do anything to the plunger, plunger spring or with the windings proper. I did accidentally drop the bottom cap which caused the two wiring leads from the winding to break off of their soldered terminals. This made them too short for me to reattach so I did have to solder wire onto the the nubbins of the winding leads, covered with shrink tubing. Then the extended wires were soldered into the external terminals and trimmed. I had also filed and polished all of the larger contacts inside and applied a coating of dielectric grease. Tested Relay with battery charger on winding terminals and VOM meter across battery terminals. Good resounding clunk as terminals made contact and 0 resistance across battery terminals.

So it ain't new but its better. Please feel free to take your pick of emojis 😁😚🤪😵‍💫😲🤔😍🤡
 
DavidH said:
It has been discussed many times, but don't solder wires on a LAV unless it is the only way to make a connection such as in a handlebar switchblock. large number of technical reasons which I shall not repeat, but as John states, being 3 hours from home ......

You should be able to get the larger starter motor cable crimped to suit by an auto electrician, even in the 'land of the free'. probably make up exactly what you want.
Here is AUS, auto electricans are a dying species, on the endangered species list.

As has been stated, if using the original or new starter relays/solenoids, it is good practise to heat shrink over the termination once tightened, and proven to work properly. Just the normal heat shrink. I would not recommend the one with internal 'glue'.
Generally there is not much space between terminals on these devices.

Remember, Murphy is alive and well. and just LUVS old motorcycles.
Good luck.
Click to expand...
Hello David, I had to, just had to, solder wire to extend the winding leads otherwise the entire Relay would have become a paperweight. So far my on the bench testing signals a good functioning Relay. We'll see how it actually works once I get the sprag clutch resolved.
As for Murphy 👺I think my garage needs an exorcism. 🙏
 
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