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Vintage Kosman Hub/Rim project 03 Nov 2023 07:15 #891256

  • z1kzonly
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H All, I had to buy this set up! Of course this hub needed some saving. No welding, just 4 Heli-coils. I upsized to 3/8" bolts.  And I turned .015" of ugly off the sprocket adaptor.
Common Z1 / KZ Double Weld Drag Bike Rim back before they made wide rims.
Hubs are universal, same both sides. This one has 2 - 3/16" flanges.
My questions are? Can the 4 bolt disc just use the 4 bolts instead of 8?
Plus this one must have used the sprocket extra spacers, which in turn, took sprocket off of flange. Then proceeded to elongate the holes.
So until I polish this whole rim ring! Winter project. I can not tell until it's laced. To see if I need a spacer at sprocket? Most likely had the bigger drag slick on it?
And try and find an old school spoke trueing person! I can get it together, but do not have time or patience to true it up!
But this will be a street tire project. 180? 200? Or a Grooved cheater Slick! 
I know a couple of you old timer drag bike guys might have some info!
Thanks in advance!

Marty in Buffalo
Livin in "CheektaVegas, NY
Went thru 25 of these in 40 yrs.
More room for The Old Girl, Harley 75 FLH Electra Glide,
Old faithful! Points ign. Bendix Orig. carb.
Starts everytime!


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Vintage Kosman Hub/Rim project 04 Nov 2023 14:52 #891284

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Hey Marty
My 2cts is 
8 bolts is what I would do 
Where holes were oblonged  . Did the bolt have a shoulder , or was it threaded where it had bearing against the  disc or sprocket ?
Can you  check sprocket clearance by finding the overall tire width of the chosen tire vs the  disc / sprocket assembly and pull some figures from that to see if you are at least close
I mentioned in another thread I found in my secret stash a 1980 Kosman  catalog with price sheet if I can look up anything in the future you may need
And I can e mail you the pages you may want 

Original owner 78 1000 LTD
Mr Turbo Race Kit, MTC 1075 Turbo pistons by PitStop Performance , Falicon Ultra Lite Super Crank, APE everything. Les Holt @ PDM's Billet Goodies . Frame by Chuck Kurzawa @ Logghe Chassis . Deep sump 5qt oil pan. RIP Bill Hahn

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Vintage Kosman Hub/Rim project 05 Nov 2023 06:37 #891314

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I have a NRC catalog from 1988 that calls out the Kosman wide rim at 5-3/4" x 18" that will fit a 8-1/2" wide slick. Listed cost back then was $500.

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