Many of the stock non-adjustable forks for Monsters leave a bit to be desired. For anyone heavier than 180# they often feel soft. New springs, oil, or internals can fix this but are pricey and take some skill to install. While not a complete solution adding some preload can make things much better for very little money and time.
I have an '03 800 Dark with the non-adjustable Marzocchi forks. The stock progressive springs are too soft for me at 215# and the front end tends to wander in turns. I'm going to get new springs and oil but in the meantime I decided to add some preload with fixed spacers.
WARNNG:If you do this you will be working on your bike while it is propped up and not supported by its wheels. Always make sure the bike is stable and do not do anything to de-stabilize it. If you are going to turn a wrench, press on something, or apply any force make sure it is stable enough before you do it. Please keep you and your bike unharmed.
THE PARTS:You'll need to get some material for spacers. Basically, this should have the same inside and outside diameter as your springs. That way it will sit nicely on top of the spring and the dimpled washer that holds the top of the spring will seat nicely into it. You can use metal tubing of the right diameter. You can use PVC, but if you do use a metal washer between it and the spring so the spring doesn't chew shreds off and deposit them inside the fork.
For my 43mm Marzocchi forks I have springs with a 38mm outside dia, 28mm inside dia. I found a 1" electrical conduit connector was just right and only cost $1.50. The dimpled washer seats nicely inside and the flanges at the end sat nicely on top of the springs.
This is what it looks like:
And this is what it looks like once I cut the ends off at an 11mm height.
I cut them easily by hand with a hacksaw, cut off the nubs the screws mount in, and sanded it all smooth. I originally measured the sag on my front end (48mm) and made some 15mm spacers to get the sag to where I wanted it (33mm). This left things a little harsh and stiff so I stepped down to 11mm. Measure your own bike to determine where you'd like yours to end up.
http://www.ohlins.com/Motorcycle/Settingupyourbike/tabid/59/Default.aspxOnce you find your material, cut your spacers to length making sure they are the same height all around, sand the edges smooth, and clean off all shavings and dust. You don't want any of that crap in your forks.
PREPPING THE BIKE:You'll need to set the bike up with the front wheel supported off the ground and the bike secure enough to wrench on. I set my bike up on a rear stand. I then lifted the front wheel with a front end stand. If you don't have a front end stand some burly friends and careful lifting might do. I used two jack stands with a 2x4 across them to support the bike under the front cylinder.
THE INSTALL:Now get down to business. Cover the tank and front fender with a blanket or towel so you don't scratch them. Unbolt the gauge cluster and just let it gently hang to the side. Remove the bars and fasten them out of the way of the fork top caps. I zip tied mine to the unused fairing brackets.
Loosen the 6mm Allen head pinch bolts on the top triple clamp. Then break the fork top caps loose. Unscrew the fork top caps all the way. Once they are both free CAREFULLY raise the front wheel and prop it up. This will slide the springs and fork innards up. Be careful not to unsettle the bike while you are doing this.
Break the fork top caps loose from the lock nuts underneath. Remove the top caps and set aside. What you have will now look like this:
Now you need to get the dimpled washers out. An extra set of hands can really help here. They're slotted so you probably don't need to remove the locknuts.
If there's not much preload pressure you can wrap your hand around the spring, press down, and slide the washer out from under the lock nut. If that is too tight, loosen the lock nut up to the top of the damper rod and try again. As soon as you remove the washer the damper rod and the lock nut may start to slide down into the fork so grab a hold of it. If you lose it just slowly remove the spring and extend the damper rod again. The spring will drip oil so have a rag handy.
Now install the spacers you made. You can place it on top of the spring, press down, and slip the dimpled washer between the spacer and locknut. Too tight? Unscrew the locknut all the way to the top and try again. It should look like this:
Screw the locknuts down far enough that you can spin the top caps on all the way without contacting the locknuts. You want all the threads you can get in the top caps. Now tighten the locknuts against the top caps.
Now carefully remove what is holding the front wheel up and let the springs settle back into the fork. Carefully get the top caps started in their threads and torque them to spec. Torque the pinch bolts on the top triple to spec. You really want a torque wrench here. Too loose and the front end can come apart, too tight and you crush the top of your forks.
Reinstall the handlebars. The arrows on the clamps face forward and the gap at the front should be slightly smaller than the gap at the rear. Remount the gauges.
Lower the front end down carefully. Make sure the kickstand is down and take the bike off the rear stand. You're done.
Double check all your fasteners, check you sag, and go for a test ride.
Again, this is not going to give you an optimal setup but for heavier riders it can greatly improve the stock, non-adjustable front end for a few dollars. If you want a little more or less preload, make some new spacers and swap them in. When I did my second set of spacers it only took an hour to cut and install them with a test ride and taking pics for this tutorial. Not as easy as laying a wrench to an adjustable fork but worlds better than stock and very inexpensive.
Oh, and here's a really nice 2 part video of an upside down cartridge fork rebuild to give you some idea of what lives in there:
Change motorcycle fork seals part 1 (of 2) cartridge typeChange motorcycle fork seals part 2 (of 2) cartridge typeScott
