Sprag clutch repair

Dellortoman said:
Max safe temp is around 80C for most magnets. You may be able to sneak up to 100C for some specific magnetic materials, but I wouldn't risk it. If it sizzles when you spit on it, you've overcooked it.

While on the subject of magnets, don't drop them on the floor or hit them with a hammer either.

If your alternator rotor is stuck on, heating it or belting it with a sliding hammer could bugger its permanent magnets. I've seen both of those methods used on other bikes
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80C okay - didn't know that, I'd have guessed higher. Thanks.

I'm thinking...mini-blowtorch on the tips of the M8 screws and try to press out the roll-pins. If any of them don't budge...think more.
 
I've not tackled a Laverda sprag clutch myself. But roll pins generally shouldn't be hard to remove. Just get yourself a set of pin punches (they're not expensive), select the appropriate sized punch and gently tap the pins out.
 
1drv.ms

P1000995.JPG

JPG Image
1drv.ms
This modification of the starter freewheel might seem unessential, but in my experience it is usually these springstop bungs tilting that`s the beginning of the selfdestruction of these starter clutches.
My RGS is high mileage 220 000 km, and since this modification more than 50 000 km ago it has worked excellent.
Locktiting screws is of course a must.
Hope the picture can be seen.
 
Arnstein said:
... usually these springstop bungs tilting that`s the beginning of the selfdestruction of these starter clutches.
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Interesting picture - I think I see what you mean. On my (deceased) ramp ring the tips of 2 plungers were snapped off and rotated in the ends of their holes. When they came out then the remaining cylinder of the plunger and spring just fell out.

Then when the ring came out, i could see how they'd made it by drilling from the outside in then plugging the outside of the hole. so you're saying that plug is sort of concentric with the circle, therefore at an angle to the plunger - but have you made new plugs, or put an angled spacer down in the hole? No, that would just rotate, so you must have made new plugs/bungs for the holes?

I'll see what the ramp ring I get from Wolfgang (Tuesday) looks like - thanks for the warning.
 
Yes made new bungs that will be square to the spring / plunger. If you magnify my picture you will see my text on it. Also read my earllier text ( thursday ). The reason the original bungs tilt is because of the centrifugal force pressing the rollers / plungers / springs against bungs all the time when motor is running, the bungs are very short only supported at one corner and as said will tilt and of course the spring too, this tilting damages the springs. and the selfdestruction has started.
 
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Dellortoman said:
Good bit of engineering detective work Arnstein. Nice clear explanation in your drawing too. (y)
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Thank you, I was fedup of the starterclutch trouble so when really investigating the parts I discovered that these bungs had tilted and as said really is the start of trouble.
The 3 screws on it turning loose is of course also part of the trouble, so locktite.

After this modification and with the right type of plunger springs the rollers will of course, because of centrifugal forces when motor starts, leave the freewheel gear completely and not touch it at all until motor stops.
 
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I got the new parts from Wolfgang today and assembled the clutch. I can't start the bike for the acid test because of the clutch slave problem (another thread) so there's no oil in it, but turning it by hand it felt smooth and gripped in one direction.

Referring to Arnstein's info about the perpendicular base of the plunger holes - looking at my new ramp-ring I think I see what he means.
new ramp ring.jpg
So that plug in the hole gets hammered off-perpendicular by the plunger which then destroys itself - and his modification is a longer plug that's braced by the ID of the outer ring, as seen in his excellent picture. Good idea and I'll do that one day but for now I just want to ride this bike once then see everything it needs.

I assembled the slave with grease as Paul suggested in this thread

Grinding sound when press starter - RGS

Hi everyone. I?ve got a problem I hope I can get some help with. When I press the starter button on my RGS, a grinding sound comes from the within the motor somewhere. The motor didn?t appear to be turning over, just this grinding, meshing sound. I had ridden a few blocks from home when it...
www.laverdaforum.com www.laverdaforum.com

where Piet also explains how to tighten the little M5 screws (loctite, tighten, hit socket with hammer gently, tighten some more, keep going til it doesn't move any more) - as Piet said I was amazed at how much more it moved after a tap. Looks like this when done.

starter clutch assy.JPG

I used Paul's method from that thread to get it on the freewheel hub (grease it, push on hard, rotate clockwise still pushing until it slips over) - worked on the 2nd go. No nuts on wires needed.

So thanks very much for all the help with this one everybody. Now back to the clutch slave.

-Richard
 
It looks great, Richard, nice work!

Wolfgang has suggested that I remove my sprag and inspect and lube it thoroughly before attempting to use it to start the engine. How did you remove the sprag in the first place? Did you use a puller or is there a special tool that you used?
 
If it's not come off in a long time, it'll likely be a bit stubborn.
Wrap in in something when you pull it off to stop rollers, plungers and springs flying all over the place.

Paul
 
Franco58 said:
It looks great, Richard, nice work!

Wolfgang has suggested that I remove my sprag and inspect and lube it thoroughly before attempting to use it to start the engine. How did you remove the sprag in the first place? Did you use a puller or is there a special tool that you used?
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I got an M16x1.5 bolt and screwed it into the rotor. The Green Book says something like "then a few light taps" - but that didn't work so I drove in the bolt with an impact wrench and it came off the taper immediately. No damage.
 
The front wheel spindle can be used but the bolt method is better IMHO, not a big fan of giving the end of a crankshaft a tap with a hammer, no matter how lightly.
Just take the spindle nut down to your friendly bearing/nut and bolt emporium and they'll be able to provide you a suitable bolt for a few bucks. Getting hold of a rattle gun and socket might be a bit more difficult.
 
Rob said:
You don't need to do that - only applicable to Nippon Denso equipped triples AFAIK. The front wheel spindle can be used for that job.
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I tried the spindle and couldn't get it to work hence the bolt - but yes this is a Nippon Denso alternator rotor on an 82ish triple, I should have said that - don't know what works for other eras.
 
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