I've been looking to upgrade my fairly stock(stiffer springs) suspension. I was going to get the
Racetech cartridge emulators but I came across
Andreani drop in cartridges for a decent price from
http://www.fastbikeindustries.com/ (FBI)
The installation is very similar to a fork seal replacement. You'll need all the same tools plus a hand held grinder. Also, the recommend oil is Ohlins Fork Oil 2.5W #01312, but general 5wt fork oil works as well.
Using
http://www.ninjette.org/forums/showthread.php?t=23200 as a guide, completely disassemble your forks.
The bottom of the inner fork tube has bushing inside of it. The inner diameter of the bushing is smaller than the outer diameter of the cartridge, so the bushing needs to come out.
As you can see, the bushing is held in place by a pressed lip. Use the grinder to remove the lip.
Take a smaller pipe and punch out the bushing from the other side.
The bushing looks like
Clean up the grounded off lip.
Screw off the cap and adjuster from the cartridge. The bottom part off the cartridge is bolted to the outer fork in the same manner as the damper rod.
Use something to hold the cartridge in the center of the outer fork opening.
Put on a new copper washer and torque to 20nm. DO NOT PUT ANY LOCTITE on the threads. It doesn't matter which side compress and rebound is on but its "standard" to put the rebound on the right side.
Install the seals, bushing, and washers as described in the
fork seal DIY. Remember to keep the damping rod extended or else you'll have to fish it out of the forks. Tie a string or wire to the damper rod because you'll need to push it in and out to bleed the air out. Pour the oil into the forks.
If possible, use a funnel to pour the oil directly into the cartridge tube. This make bleeding the air much much easier.
I was told a useful tip by FBI on how to bleed the air out. Extend the forks and place your hand over the top and push down. This should create pressure in the forks. Then compress the fork all the way down. Put your hand over the fork top and pull. This will create a vacuum. Doing this a couple of times will get some oil into the cartridge, then just push and pull the damper rod to finish the bleeding. The airgap is 115mm measured with the forks and damper rod fully compressed. Springs are not in yet.
After the oil level is set, insert the springs, plastic preload adjuster and screw on the top cap.
Make sure the compression/rebound screw is all the way out. You don't want the needle bottom out as you are screwing on the cap.
The top cap should be turned in enough so the adjuster has three full turns from closed position to fully opened. The picture below has some preload, its easier to screw in the top cap with no preload.
Insert the top cap into the fork and insert retaining ring. Start with the compress and rebound at 1.75 turns out.
