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- Nov 26, 2009
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Believe it or not you can make a few small "do it yourself" modifications to your stock Norton forks and get modern style compression damping and improved rebound damping.
The 1st thing to do is check for wear in the aluminum caps. New caps measure .380" ID. Get new ones or drill to 13/32" and loctite (red) in a sleeve of .375" ID .015" wall K&S brass tubing (available at hobby shops). You can get new brass caps at Decentcycles.com. Clearance must be tight or you won't have enough rebound damping.
REBOUND DAMPING:
To improve rebound damping. Place the damping cup on a socket. Tap carefully with a hammer and a tapered carpenter plumb bob to swell the open end to approx .677" (anywhere between .675" to .680").
COMPRESSION DAMPING:
If you have these type of damp tubes then its easy to cover the holes below the conical section with JS alum sleeves (or make your own) and drill only one 1/16" diameter hole in the middle of the conical section (not shown). This will give you some compression damping. The stock setup offers no compression damping whatsoever. You don't want too much or you will get a harsh ride. One 1/16" hole in each tube works out just right.
If you have damper tubes with holes in the conical section. Silver solder a couple brass plugs into the holes. Be careful not to insert the plugs so deep that they interfere with the damper rods (you should not be able to see them on the inside). Smooth them off and drill one of the plugs with a 1/16" drill bit. There must be no other exposed holes.
Use 15 to 20 wt oil.
For more info and how to eliminate fork oil leaks go to:
http://www.jsmotorsport.com/technical_Fork_upgrades.asp
The 1st thing to do is check for wear in the aluminum caps. New caps measure .380" ID. Get new ones or drill to 13/32" and loctite (red) in a sleeve of .375" ID .015" wall K&S brass tubing (available at hobby shops). You can get new brass caps at Decentcycles.com. Clearance must be tight or you won't have enough rebound damping.
REBOUND DAMPING:
To improve rebound damping. Place the damping cup on a socket. Tap carefully with a hammer and a tapered carpenter plumb bob to swell the open end to approx .677" (anywhere between .675" to .680").
COMPRESSION DAMPING:
If you have these type of damp tubes then its easy to cover the holes below the conical section with JS alum sleeves (or make your own) and drill only one 1/16" diameter hole in the middle of the conical section (not shown). This will give you some compression damping. The stock setup offers no compression damping whatsoever. You don't want too much or you will get a harsh ride. One 1/16" hole in each tube works out just right.
If you have damper tubes with holes in the conical section. Silver solder a couple brass plugs into the holes. Be careful not to insert the plugs so deep that they interfere with the damper rods (you should not be able to see them on the inside). Smooth them off and drill one of the plugs with a 1/16" drill bit. There must be no other exposed holes.
Use 15 to 20 wt oil.
For more info and how to eliminate fork oil leaks go to:
http://www.jsmotorsport.com/technical_Fork_upgrades.asp