RGS sprag clutch flywheel removal

murphus

murphus

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Lost in the Midwest
Taking the sprag clutch apart on my '83 RGS. I've never serviced it and while I haven't had any issues I figured best to get in there before things go wrong. My RGS has about 75,000 miles on it, a bit over 30k put on by me. Not surprisingly, someone's been in there before, evidenced by the red loctite that had been applied to the 10mm bolt securing the flywheel/sprag clutch to the crank. Said bolt came out with a rattle gun, but the flywheel won't let go of the crank. I'm using a 10.9 16mm bolt to remove the flywheel. Initially used a 24mm box-end wrench striking it with a heavy hammer to try and remove the flywheel. No go. Then applied the rattle gun. No go. Should it be this hard to get the flywheel to let go? Suggestions for locking the crank to get better effect? Assuming I get it apart, will be interesting to see what I find as there's metal swarf evident in the flywheel, stuck to the inside edge. Also, there was no thrust washer on the outside of the idler gear. Should there always be one?IMG_4245.JPGIMG_4244.JPG
 
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Another comment on metal adhesives, ie "Loctite" most of the product range has an upper temperature to adhesive strength rating, upper limit is around the 90 degrees C. There are higher working temperature adhesives, need to check the application data from the manufacturer or distributor. My iis test jig had high power resistors on a metal platform to test all manner of adhesives and epoxies in a working jig. 90C was the limit for low strength 242 and others, even stud lock was at 90C. Have measured internal crank case working oil temperatures ( imbedded a temp measure semi conductor into a Hall Effect pickup for a duc ) 90C to 140C the latter upper figure a very hot summers day stuck in stalled traffic, duc S2 millie motor. HTH j.
 
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Indeed Chris, how i loosen fasteners that have adhesive, warm to about 80-100C if possible, working forwards and backwards in about 30 degree range, seems to flog the adhesive into none binding state. Have not rechecked on the modern application temperature for metal adhesives, also dependent on the substrate materials, ie steel bonds quicker than non ferrous as i recall. Others may correct me with updated application data. HTH J
 
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Interesting conversation, suggestive that Loctite in this application might have no real benefit? The Loctite data sheet I found shows an upper service limit of 149C (300F) and suggests localized heating to 250C for release. Data sheets for Permabond red show a rapid drop in strength starting at approx. 110C, save for their listed HH131 High Heat formula, which retains 60% of its strength at 200C, falling to 20% at 250C.

It wasn't until I'd removed the bolt in question that I knew it had Loctite applied, but even if I had, I'd be concerned in this particular application about applying heat for fear of not being able to control the heat application and demagnitizing the flywheel. I wonder if an inductive heat tool would be approrpriate?
 
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murphus said:
Interesting conversation, suggestive that Loctite in this application might have no real benefit? The Loctite data sheet I found shows an upper service limit of 149C (300F) and suggests localized heating to 250C for release. Data sheets for Permabond red show a rapid drop in strength starting at approx. 110C, save for their listed HH131 High Heat formula, which retains 60% of its strength at 200C, falling to 20% at 250C.

It wasn't until I'd removed the bolt in question that I knew it had Loctite applied, but even if I had, I'd be concerned in this particular application about applying heat for fear of not being able to control the heat application and demagnitizing the flywheel. I wonder if an inductive heat tool would be approrpriate?
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Rare that from what experience i have, that in situations where heat would damage the fastener removal, the bonding of adhesive cannot be overcome with firm purchase pressure, notably "working" the threads in back and forth action as mentioned, seems to be a "friction" effect upon the actual adhesive increasing its own higher localised thermal condition over ambient temperature of the steel or what ever. A best guess, as to the real reason for this shuttling of the adhesive to allow a release of the fastener. Well done Murphus, modern adhesives data is different from 20+ years ago. Shelf life another notable of the adhesives, another topic, another time. j.
 
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Ventodue said:
Tip for when you eventually get to the re-assembly stage, Murphus.

Make sure that the 3 countersunk screws that hold the freewheel cover plate on are done up well. Part number 30 382 043, piece 37 on the Albero Motore page of the parts book.

If not, they can unscrew and, in extremis, do immense damage to the starter motor - trash it, basically. DAMHIK.

Piet's advice is to give the head of the screws a wrap with a punch once you've done them up and then retighten. Tom Eatman - and I, I confess - (also) use a bit of Loctite.
View attachment 65040
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Spot on re screws backing out, end up with this...my bike too....ouch.... used the carcass and another faulty SJCE starter motor to make a "new" one.... There are folk here that can save you 1000's of dollars in repair cost, if not what to check for in routine maintenance, j.
 

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Got the thrust washer for the idler gear. Local bearing supplier, Torrington AS1024. They also had the caged needle bearing for the sprag drive gear. Before I offer it all up, which is best for the needle bearings? Oil or grease before installing?
 
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