Author Topic: Check your sprag bolts !!!  (Read 5363 times)

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gashousegorilla

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on: November 29, 2018, 03:53:00 am
 
       Once a season at least !    Just a reminder.... it's a good thing to do .   It can certainly avoid ruining your day with catastrophic failure.   If the engine sprocket/sprag retaining bolt spins out, it could wedge itself under the primary chain and snap it sending it through or cracking the case and or left side cover.   It can also lock up the rear wheel if it gets wedged under the primary chain... NOT GOOD !   We  have seen this before, and the factory updated the torque spec and bolt sometime ago.  The torque spec NOW is 48 ft lbs, with loctite  270 applied.  ME ? ..... I put red Loctite on it and slam that bolt in with a impact gun ! :o    The bolt thread's into the crankshaft  in a clockwise direction.... however.... the crankshaft and engine sprocket/ sprag gear rotate COUNTER clockwise on the left side.   This can tend to loosen the bolt.   Another example that I found, after noise was heard behind the left side cover. The sprag gear was loose , and walking in and out a bit on the crankshaft , making a chain slapping noise on occasion......
« Last Edit: November 29, 2018, 02:18:34 pm by gashousegorilla »
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heloego

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Reply #1 on: November 29, 2018, 12:29:34 pm
   Ooh! Good advice, GHG!  :o
   Odd that they wouldn't have included some sort of locking system for the bolt.
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9fingers

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Reply #2 on: November 29, 2018, 01:09:42 pm
Mr. Gorilla, why is your chain so clean? What lube do you use? Thanks for the really good tip.
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gashousegorilla

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Reply #3 on: November 29, 2018, 02:23:41 pm
   Ooh! Good advice, GHG!  :o
   Odd that they wouldn't have included some sort of locking system for the bolt.

   Or at least tap a left handed thread on that side of the crankshaft already !  Geez... I guess telling people to just tighten the bolt more is a cheaper option for them ?!   :o

Mr. Gorilla, why is your chain so clean? What lube do you use? Thanks for the really good tip.
9fingers

  That is the primary chain, which lives behind the left side cover... it runs in a bath of motor oil.  ;)
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Bert Remington

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Reply #4 on: November 29, 2018, 04:38:22 pm
While not as popular as oil threads, fastener threadlocker threads can be just as exciting.

As you try, like me, to choose the correct threadlocker from Loctite or Permatex you will enter a wilderness of product evolutions and corporate handoffs.

Putting on my fire suit, here's an overview:

Blue: medium strength; disassemble with hand tools
Red: high strength; may or may not require high heat to disassemble with hand tools
Purple: low strength; disassemble with hand tools
Green: wicking (penetrating already assembled fasteners); medium/high strength; not sure about disassembly

As you examine the product comparison charts, be careful to note publication date.  For instance, Loctite 270 seems to be a recent introduction, perhaps related to the Henkel handoff.

So which Loctite to use?  My recommendation if your sprag bolt has not loosened, then Loctite 270 after cleaning and proper torque including 24 hour cure period should be sufficient.  If your sprag bolt has loosened itself as shown in Mr Gorilla's photos then I recommend a Loctite that requires heat for removal (eg Loctite 263) because the threads are probably a bit worn from vibration and need the extra help.

I noticed the bolt head doesn't have a strength/grade marking.  Finding a marked substitute with a shoulder is a consideration.  And maybe adding a Nord lock washer?  If anyone goes down this path, please post OEM and p/n.
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longstrokeclassic

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Reply #5 on: November 29, 2018, 05:07:30 pm
How anyone would think they can improve on Enfield's self aligning drive sprocket technology with a few simple drops of thread locking compound is beyond me!


Narada

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Reply #6 on: November 29, 2018, 06:33:26 pm
What if a solid physical stop were attached to the inside of the cover?  ???

Maybe drill and tap through the cover, and run a large bolt in, cut to length with thread lock and sealed, adjusted to leave maybe 1/8" clearance between the new cover bolt/drive sprocket bolt stop, and drive sprocket bolt?  ::)

That might prevent the drive sprocket bolt from ever backing too far out. You probably could even mount a sensor or switch to the new stop to let you know your sprocket is falling off again! :o
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Bert Remington

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Reply #7 on: November 29, 2018, 06:49:28 pm
Narada -- Grant was right: "I will be done.  That's it.  I will just leave it alone. Really. You can trust me...  ;)" How soon forget our promises.  That what owning an RE does to you.
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9fingers

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Reply #8 on: November 29, 2018, 09:44:48 pm

  That is the primary chain, which lives behind the left side cover... it runs in a bath of motor oil.  ;)


Shows what I know.......DOH! This is my first bike, in 49 years, that has the drive chain on the right side.........had me confused........not hard to do. Thx
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Aus.GT

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Reply #9 on: November 29, 2018, 10:08:26 pm
Hey Grilla, Your just beating on it too hard. ;)
I see it's just starting to rub the cover, caught that just in time.
Hows the chain look must have been flexing left a lot.
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gashousegorilla

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Reply #10 on: November 29, 2018, 11:24:26 pm
What if a solid physical stop were attached to the inside of the cover?  ???

Maybe drill and tap through the cover, and run a large bolt in, cut to length with thread lock and sealed, adjusted to leave maybe 1/8" clearance between the new cover bolt/drive sprocket bolt stop, and drive sprocket bolt?  ::)

That might prevent the drive sprocket bolt from ever backing too far out. You probably could even mount a sensor or switch to the new stop to let you know your sprocket is falling off again! :o

  I like it .   And a fail safe basket to catch the bolt too ! ;D


While not as popular as oil threads, fastener threadlocker threads can be just as exciting.

As you try, like me, to choose the correct threadlocker from Loctite or Permatex you will enter a wilderness of product evolutions and corporate handoffs.

Putting on my fire suit, here's an overview:

Blue: medium strength; disassemble with hand tools
Red: high strength; may or may not require high heat to disassemble with hand tools
Purple: low strength; disassemble with hand tools
Green: wicking (penetrating already assembled fasteners); medium/high strength; not sure about disassembly

As you examine the product comparison charts, be careful to note publication date.  For instance, Loctite 270 seems to be a recent introduction, perhaps related to the Henkel handoff.

So which Loctite to use?  My recommendation if your sprag bolt has not loosened, then Loctite 270 after cleaning and proper torque including 24 hour cure period should be sufficient.  If your sprag bolt has loosened itself as shown in Mr Gorilla's photos then I recommend a Loctite that requires heat for removal (eg Loctite 263) because the threads are probably a bit worn from vibration and need the extra help.

I noticed the bolt head doesn't have a strength/grade marking.  Finding a marked substitute with a shoulder is a consideration.  And maybe adding a Nord lock washer?  If anyone goes down this path, please post OEM and p/n.

  Very good idea Bert ...  the Nord lock washers are on order, and I'll let you know.  ;)    But it's still gonna get some red loctite and an impact gun ... and maybe a cheater pipe too ?    ;D


 
  That is the primary chain, which lives behind the left side cover... it runs in a bath of motor oil.  ;)


Shows what I know.......DOH! This is my first bike, in 49 years, that has the drive chain on the right side.........had me confused........not hard to do. Thx
9fingers

  No worries...  ;)


 
Hey Grilla, Your just beating on it too hard. ;)
I see it's just starting to rub the cover, caught that just in time.
Hows the chain look must have been flexing left a lot.

 

  Ya think ?   ;D        The the chain looks good.... the auto tensioner however, is thrashed.   The upper row of teeth , which the spring mechanism  engages in, are warn off.   So the mechanism released and dropped ... bringing the chain with it.    So slack chain , with no tension.   

 BTW... for those who don't know, that plug on the top of the left side cover is a primary chain inspection hole.   If you remove it and stick your finger in there  and push up on the chain...  It should feel tight with very little play, if any at all.  If it flops around or is easy to push ?..... you got a problem in there.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #11 on: December 02, 2018, 10:04:43 pm
   OK...  I THINK I have gotten to the bottom of this bolt fiasco.   If you'll notice in the  picture I posted above... the bolt has NOT spun out, but also has not dropped out.    That is because this particular bike is an early UCE engine-ed G-5 motor.  The G-5's have/had different  left and right side engine covers, and rocker boxes then the C-5's.   The left side cover that we are looking at  here,  on the G-5 , is flatter and not as rounded or bulges out as much as the more common C-5 and B-5 models.     In the beginning, back in 2009 , it was just C-5 and G-5 here in the states... two different style left side covers.   

  Should the bolt spin out.... as it inevitably will because it's not a left handed thread ....  On a G-5 the head of the bolt will bottom out and hit the inside of the left side cover.... while there are still a few threads of the bolts still in the crankshaft....  and preventing the bolt from dropping and causing mayhem.    Loose ain't good, but at least it ain't tearing up the primary chain and the left crankcase and cover should it fall ... I guess they were thinking ?!   ::)    They "achieved" this  by the length of the bolt ... leaving it too long, to thread all the way into the crank shaft, and also using a thick washer/ spacer.   So when the bolt spins out, it hits the cast "Ribbing" on the inside of the cover.....

  The left side cover on this G-5 CAN NOT be pushed on with the bolt un-threaded  near it's end.   If you look closely at the pic's, you can see some scaring on the inside of the cover, at the ribbing where the head of the bolt was hitting...
« Last Edit: December 02, 2018, 10:13:51 pm by gashousegorilla »
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #12 on: December 02, 2018, 10:30:25 pm
   Some more shots....
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #13 on: December 02, 2018, 10:34:55 pm
   The bolt and spacer in question... 
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gashousegorilla

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Reply #14 on: December 02, 2018, 10:47:33 pm
   These covers style's on the G-5 did not last very long , and the bike was gone after a couple years.   After that, the bikes here in the states  all had the different "winged "  more rounded  C-5 type cover.    Around 2011 there was a service bulletin , which mentioned a different bolt , thick washer , loctite 271 and increasing the torque spec .     Ummmmmm ?.....I'm wondering it that old style G-5 bolt and spacer went into some of those early C-5's  type left side covers and dropped causing mayhem  ?    ::)   I've seen it in more then one case !

   So anyway, a Nordlock  M12 -- DP NL/PR ,  part number 0129510  from Fastenal here in the states, will be tried with the bolt and red 217 Loctite....     
« Last Edit: December 02, 2018, 11:06:34 pm by gashousegorilla »
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.