Fxdx pulley bolts snapped
#71
07-08-2023, 07:12 PM
Club Member
WOW, It appears once the bolts were loose or just the torque action of the assembly of the wheel and pulley was so great loosing them that it stripped out the 12 point hex in the locking plate.
Lock wire would not have prevented them from loosing. Although wireing does show some evidence of keeping a bolt tight, it's more to prevent a loose bolt from falling out.
Lock wire would not have prevented them from loosing. Although wireing does show some evidence of keeping a bolt tight, it's more to prevent a loose bolt from falling out.
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Max Headflow (07-08-2023)
#72
07-08-2023, 07:29 PM
Seasoned HDF Member
Easy, see if it can be tightened.. If so remove the bolt clean the hole and re-loctite. In the case of a pulley also check if the pulley is loose. When it comes to rear pulley bolts, it's extra work over a service..
#73
07-08-2023, 08:35 PM
Club Member
#74
07-08-2023, 11:41 PM
Road Warrior
Your saying the 7/16 (.437 ) threaded factory bolts have a unthreaded shoulder area that is .389.
That would be a bolt with a rolled thread rather then a cut thread.
Tapped holes are produced in that way too in some materials. The tap drilled hole is cut larger then a normal tapped hole.
Usually this is only done in low grade material. That swagging action of the forming increases the strength but not anywhere near class 8.
It appears the original posters bolts are rolled threads with.437 bodies.
Only the thread area was made smaller for the rolling process. Note the increase in size at the end of thread. That small area is were the thread rolling process didn't swage up the material.
The company that made the locking plate shows class 5 bolts. Not class 8 as required by Harley. There really the ones in fault here for saleing something that doesn't do what it claims.
However they still had to get loose and let pulley and bolts come out bending and breaking them.
No Loctite was used and the torque was juggled to align locking plate.
However, obliviously, the 5 locking plate bolts must have fell out also .
Never has been determined if that bolt is just a very short bolt in the two part locking plate or was wheel drilled and tapped by the mechanic.
I guess your CAD sketch is from ARP bolt company?
https://arp-bolts.com/
That would be a bolt with a rolled thread rather then a cut thread.
Tapped holes are produced in that way too in some materials. The tap drilled hole is cut larger then a normal tapped hole.
Usually this is only done in low grade material. That swagging action of the forming increases the strength but not anywhere near class 8.
It appears the original posters bolts are rolled threads with.437 bodies.
Only the thread area was made smaller for the rolling process. Note the increase in size at the end of thread. That small area is were the thread rolling process didn't swage up the material.
The company that made the locking plate shows class 5 bolts. Not class 8 as required by Harley. There really the ones in fault here for saleing something that doesn't do what it claims.
However they still had to get loose and let pulley and bolts come out bending and breaking them.
No Loctite was used and the torque was juggled to align locking plate.
However, obliviously, the 5 locking plate bolts must have fell out also .
Never has been determined if that bolt is just a very short bolt in the two part locking plate or was wheel drilled and tapped by the mechanic.
I guess your CAD sketch is from ARP bolt company?
https://arp-bolts.com/
Your saying the 7/16 (.437 ) threaded factory bolts have a unthreaded shoulder area that is .389.
And No the CAM drawing is my Geometry. Not ARP
Also if safty wire is installed correctly it Will keep the fastener tight and correctly torqued!
Last edited by Blue Bob; 07-08-2023 at 11:44 PM.
#75
07-09-2023, 12:18 AM
Seasoned HDF Member
Saftey wire won't help if the foundation is allowed to collapse. Do you think that the OPs bolts unscrewed themselves?
#76
07-09-2023, 09:04 AM
Join Date: Jan 2011
Location: Southeast Michigan 15 Minutes East Of Hell
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So the locking plate is actually a two piece fixture ... The base plate ( inner ) is secured buy the pulley bolts, torqued then the heads are orientated with the outer plate ... Then the outer plate bolts are installed ... There is a whole lot going on here that puts it in the "We can't see the forest for the trees" ... Very difficult to understand why this is a recurring problem ... I'm staying tuned
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WP50 (07-09-2023)
#77
07-09-2023, 09:46 AM
#78
07-09-2023, 09:54 AM
Seasoned HDF Member
So the locking plate is actually a two piece fixture ... The base plate ( inner ) is secured buy the pulley bolts, torqued then the heads are orientated with the outer plate ... Then the outer plate bolts are installed ... There is a whole lot going on here that puts it in the "We can't see the forest for the trees" ... Very difficult to understand why this is a recurring problem ... I'm staying tuned
#79
07-09-2023, 10:00 AM
Join Date: Jan 2011
Location: Southeast Michigan 15 Minutes East Of Hell
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No doubt ... So your explanation is the inherent design of the wheel, pulley, fasteners, service procedure, inept mechanics ? ... It appears as though this doesn't happen until it has been serviced, correct? ... What is puzzling is that it can get so bad before someone realizes it's happened ... You'd think that there would be a serious racket, vibration etc
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WP50 (07-09-2023)
#80
07-09-2023, 10:15 AM
Seasoned HDF Member
Out of concern for snapping a belt, I changed over to chain at about 27000. I've had zero issues with that. 44000, I went to a 180/55-18 rear tire. One thing I did when going to chain was add an support bearing to the sprocket. No problems with it either.
I would question how you got to this place in the first place. Why was the plate installed? What other work was done to the bike leading up to the failure?
This does seem to be more of an issue with later Dynas and not the early ones. I suspect that this is because they added more offset to the pulley to clear a fatter tire..
Here is the current setup on my DX. It has an outboard bearing.
Last edited by Max Headflow; 07-09-2023 at 10:17 AM.