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: VintageTwin
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Re: belt or chain primary
« Reply #6 on: Oct 31st, 2003, 2:43pm »
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I talked to PRIMO in the past about different size motor pulleys. He told me they had no plans of making a 24 tooth motor pulley equivalent. I went to BDL and he told me that attempts to make any motor pulley other than the 23 tooth equivalent lead to belt destruction. Whatever combination PRIMO, BDL or KARATA use is what mathmatically "works" sucessfully on the machines. The biggest bane to me is having a motor that sounds and feels like it wants another gear at 65 mph. That ****s, but I'm making my machines 1-1/2", 11 mm., under OE tin, (non- vented, stock inner and outer primary covers) belt drives anyway.
« Last Edit: Oct 31st, 2003, 2:45pm by VintageTwin » Logged
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Dereborn
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'62 FLH rigid bobber(slightly in the ratbike-area...)
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Re: belt or chain primary
« Reply #7 on: Oct 31st, 2003, 9:42pm »
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Never saw a welded rear sprocket! Wonder if tradition differs in different parts of the world... Riveted of course, but also bolted. I had to change mine the other year, and was adviced to bolt it, did so and hav had no problems at all. I have standard stroke, compression and bore, SU carb and no dragracing ambitions, so I guess I don't stress it a lot. 6mm bolts with nyloc nuts anyway does the trick for me! I think it's 52 teeth now, right? how much do you guys think I have to lower that to notice any difference? 50? 48?
Cheers
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DuoDave
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Re: belt or chain primary
« Reply #8 on: Today at 12:33pm »
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A word of warning if you are dealing with a riveted rear sprocket. I had to replace mine, so I ground the heads off the rivets and went round the drum tapping them out. The last one(!) was distorted and jammed, so I gave it a slightly harder tap and an inch sqare section of the drum broke clean off. I should have remembered from past experience how brittle cast iron is. I had to buy a new drum and it was pretty nerve wracking peening the heads of the new rivets.
As dereborn says.....learn by doing.
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VintageTwin
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Re: belt or chain primary
« Reply #9 on: Today at 3:20pm »
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Anyone know of a jig (OE or homemade) that will work for replacing rear sprockets. The '36-57 Big Twins used rivets, maybe the '58 did too, but the '59 up uses rivets and dowels pins (like a rivet but bigger or vice-versa, I don't know, I'm not looking at the book). I had a chapter going on it in 2000, but I explained and sent a '63 rear drum to USATCO (U.S. Air Tool). He sent me back a rivet air gun and bucking bar (you place this steel slug on the shank) and you put the cupped end of the rivet gun on the head of the rivet and ...rat-a-tat-tat...whilst you hold the buck bar against the shank. The amazing thing that happens is that the rivet shank sticking out from the sprocket surface squashes down into a short-stacked barrel of solid steel. Mike W. at USATCO did a few trial rivets on the '63 sprocket and drum I sent him. The barrels squashed in perfect symmetry, like a machine squashed them. I tried it on the '63 drum with my new rivet gun and backing bar next to his perfect ones and my rivet barrel squashed OK, but was kinda lopsided, but the rivet was tight and I could tell, that with practice I could do better. Problem is, that when I went to Kennedy's (in Oceanside) to find a drum in their graveyard, the only drum and sprocket I could find was this '63 that had the sprocket bolted to the drum (like Dereborn mentioned). I figured it would work and be easy to remove the sprocket from the drum for my experiment. Anyway...I did all this work, and didn't realize until I had the '63 sprocket back from USATCO, that the years I am concerned with '36-59 all have separate dust rings in front of the sprocket. '63-up has a cast dust-ring on the drum!! Awww...man!! Bum-kick!. I went back on the phone to Mike W, and he said..."Oh yeah, that does make a difference". So, if you read the Palmer resto book, he talks about needing a hollow drift. OK, but I think you need a hollow drift that has a bottom in the hollow drift's shank. The bottom in the hollow shank will act like a bucking bar. The hollow will allow you to press the dust ring tight against the drum, right? And when you hit the rivet head with the gun, it will cause the rivet shank to hit the "bottom-out" of the hollow drift and cause the rivet to squash. The drift and the hollow needs to be a somewhat bigger diameter than the rivet shank diameter, so that the shank can squash and form a barrel. I think that with the new rivets tight in the holes of the drum and sprocket (even if you have to re-drill holes because the old ones are too slopped-out), that a hand held air rivet gun and a hollow drift with a bottom in the hollow would work on a dust-ring rear drum and sprocket.
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49oldschool
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Re: belt or chain primary
« Reply #10 on: Today at 3:49pm »
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huh?
: VintageTwin
Senior Member
member is online
Gender:
Posts: 104
Re: belt or chain primary
« Reply #6 on: Oct 31st, 2003, 2:43pm »
------------------------------------------------------------------------
I talked to PRIMO in the past about different size motor pulleys. He told me they had no plans of making a 24 tooth motor pulley equivalent. I went to BDL and he told me that attempts to make any motor pulley other than the 23 tooth equivalent lead to belt destruction. Whatever combination PRIMO, BDL or KARATA use is what mathmatically "works" sucessfully on the machines. The biggest bane to me is having a motor that sounds and feels like it wants another gear at 65 mph. That ****s, but I'm making my machines 1-1/2", 11 mm., under OE tin, (non- vented, stock inner and outer primary covers) belt drives anyway.
« Last Edit: Oct 31st, 2003, 2:45pm by VintageTwin » Logged
------------------------------------------------------------------------
Dereborn
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'62 FLH rigid bobber(slightly in the ratbike-area...)
Gender:
Posts: 75
Re: belt or chain primary
« Reply #7 on: Oct 31st, 2003, 9:42pm »
------------------------------------------------------------------------
Never saw a welded rear sprocket! Wonder if tradition differs in different parts of the world... Riveted of course, but also bolted. I had to change mine the other year, and was adviced to bolt it, did so and hav had no problems at all. I have standard stroke, compression and bore, SU carb and no dragracing ambitions, so I guess I don't stress it a lot. 6mm bolts with nyloc nuts anyway does the trick for me! I think it's 52 teeth now, right? how much do you guys think I have to lower that to notice any difference? 50? 48?
Cheers
Logged
------------------------------------------------------------------------
DuoDave
Full Member
member is offline
Posts: 81
Re: belt or chain primary
« Reply #8 on: Today at 12:33pm »
------------------------------------------------------------------------
A word of warning if you are dealing with a riveted rear sprocket. I had to replace mine, so I ground the heads off the rivets and went round the drum tapping them out. The last one(!) was distorted and jammed, so I gave it a slightly harder tap and an inch sqare section of the drum broke clean off. I should have remembered from past experience how brittle cast iron is. I had to buy a new drum and it was pretty nerve wracking peening the heads of the new rivets.
As dereborn says.....learn by doing.
Logged
------------------------------------------------------------------------
VintageTwin
Senior Member
member is online
Gender:
Posts: 104
Re: belt or chain primary
« Reply #9 on: Today at 3:20pm »
------------------------------------------------------------------------
Anyone know of a jig (OE or homemade) that will work for replacing rear sprockets. The '36-57 Big Twins used rivets, maybe the '58 did too, but the '59 up uses rivets and dowels pins (like a rivet but bigger or vice-versa, I don't know, I'm not looking at the book). I had a chapter going on it in 2000, but I explained and sent a '63 rear drum to USATCO (U.S. Air Tool). He sent me back a rivet air gun and bucking bar (you place this steel slug on the shank) and you put the cupped end of the rivet gun on the head of the rivet and ...rat-a-tat-tat...whilst you hold the buck bar against the shank. The amazing thing that happens is that the rivet shank sticking out from the sprocket surface squashes down into a short-stacked barrel of solid steel. Mike W. at USATCO did a few trial rivets on the '63 sprocket and drum I sent him. The barrels squashed in perfect symmetry, like a machine squashed them. I tried it on the '63 drum with my new rivet gun and backing bar next to his perfect ones and my rivet barrel squashed OK, but was kinda lopsided, but the rivet was tight and I could tell, that with practice I could do better. Problem is, that when I went to Kennedy's (in Oceanside) to find a drum in their graveyard, the only drum and sprocket I could find was this '63 that had the sprocket bolted to the drum (like Dereborn mentioned). I figured it would work and be easy to remove the sprocket from the drum for my experiment. Anyway...I did all this work, and didn't realize until I had the '63 sprocket back from USATCO, that the years I am concerned with '36-59 all have separate dust rings in front of the sprocket. '63-up has a cast dust-ring on the drum!! Awww...man!! Bum-kick!. I went back on the phone to Mike W, and he said..."Oh yeah, that does make a difference". So, if you read the Palmer resto book, he talks about needing a hollow drift. OK, but I think you need a hollow drift that has a bottom in the hollow drift's shank. The bottom in the hollow shank will act like a bucking bar. The hollow will allow you to press the dust ring tight against the drum, right? And when you hit the rivet head with the gun, it will cause the rivet shank to hit the "bottom-out" of the hollow drift and cause the rivet to squash. The drift and the hollow needs to be a somewhat bigger diameter than the rivet shank diameter, so that the shank can squash and form a barrel. I think that with the new rivets tight in the holes of the drum and sprocket (even if you have to re-drill holes because the old ones are too slopped-out), that a hand held air rivet gun and a hollow drift with a bottom in the hollow would work on a dust-ring rear drum and sprocket.
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49oldschool
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Posts: 9
Re: belt or chain primary
« Reply #10 on: Today at 3:49pm »
------------------------------------------------------------------------
huh?
Comment