'85 Honda Magna front forks rebuild - TRAC system?

Question

I'm freshening up my Magna for the new riding season, new tires, brakes, bearings, and fork seals. While I'm changing the seals, I plan on changing the fork fluid. I also want to completely disassemble the forks and powdercoat the lower fork legs, or "fork sliders".

My problem is that these forks have the TRAC system on them, and I know nothing about this. I need to know how to completely disassemble the legs, I mean down to every last o-ring and screw and spring, so I can powdercoat the sliders

I also cannot find reference anywhere as to what kind of fluid or how much to use.

Answer 1

I used to own an 83 Magna with TRAC system, and I too did powdercoat on the sliders. And the frame,the swing arm, triple tree, coolant tubes, carb covers, valve covers, etc.

It is better to start disassembling the fork while still on the bike. Center stand the bike, prop the engine. Remove brake calipers, and the front wheel. Don't remove the fender yet. Release any air in the fork. Drain the fork oil. (Optional)

At bottom of the each fork is a 8mm (or 10mm) allen bolt. I had not problem loosening these bolts. Just get a long allen wrench with an extension. It is better if there is resistance. Look out for a compression copper washer on each bolt. If you did not drain the fork oil before, it will now drain, so have a container to catch the used stinking fork oil.

(If the allen bolts won't come off this way, there is another procedure). But that is another question.

Now remove the fender. Next pry loose the fork dust cover, and pick the fork seal retaining spring with a small screwdriver, and you can pull the slider off the inner tube. You got to give it a tug. Just remember where the inside parts belong.

Then you can remove the inner tube from the triple tree. Remember to loosen the upper bolt on the triple three when removing the nut with air nipple.

As for the TRAC Sytem - The rectangular plate at the back of the slider; just unscrew everything. Nothing will jump out. Just remember where every piece belongs. There are a few rubber orings and gaskets that are reusable. It is advisable to separate the arm that holds the caliper from the slider if you are going to powdercoat. You will need a 10mm allen wrench.

Cover the inside of all openings on the arm and slider with masking tape so they won't get powder coat. (I did not do that and I spent couple of hours sanding off the powdercoat to properly fit the pieces again.)

I assume you know how to put on a new fork seal, etc. Reverse the procedure to assemble.

The oil capacity of each tube is different. The left tube takes more fork oil than the right, because of the TRAC. What I did was pour 400 cc of 2T Oil (used on two stroke bikes) on each tube and made sure the oil level is the same. You can do this with an 2 ft. aquarium hose. Mark 10 inches on the hose, (or less if you want a stiffer ride) dip the hose inside the inner tube up to the mark and suck on the other end. If you suck air, add more oil. Once you are sucking air again, stop, go the other tube and do the same procedure. Now you are sure the the oil level in even on each tube. You do this with the spring inside the tube. 10 psi on each tube is OK.

May I suggest that you also powdercoat the brake calipers and the disc rotor (the non-braking part). I did it and it looked great. A big plus when I sold the bike. Hope this answer helps.

Good luck!

Answer 2

If I were you, I would get a service manual before proceeding. You may need some (possible expensive) special tools to completely disassemble the legs.

TRAC was Honda's anti-dive system, a concept that all of the Japanese Big Four visited briefly. (Torque Reactive Anti-dive Circuit, I believe was the full name.) Braking force rotated the calipers forward, causing an orifice in the fork to be closed. This forced the fork oil to take a path through a smaller orifice, thereby increasing the resistance to fork compression.

I would probably look at disabling it and getting slightly stiffer springs instead. I've had Progressive Suspension springs in my 1981 CB750F for eons, and they're excellent. You should go with the stock quantity of fork oil (hence the manual) but you might want to use the next grade thicker (i.e. SAE-20 rather than SAE-15).

I'm an aggressive rider and prefer a firm ride to maintain stability and control. I use 30-weight oil. It's unlikely you would want anything that heavy.

If your forks have a drain bolt at or near the bottom, you can always play with oil viscosity later. If not, it's a big pain, because you have to siphon the old oil out in order to change it, and it can be impossible to get it all out without inverting the forks to pour it out: Off they come again!

Answer 3

Honda Front Forks

Answer 4

you can do it know problem just jack up the bike and have the front wheel off the ground then remove the brake calipers then remove the wheel then remove the forks you will need tools and a snap ring tool also remember how every thing came off because its very important to assemble it back exactly you will also need to fabricate a tool from pvc pipe to install the new fork seals

Answer 5

Drill into the screw till the top of the screw breaks off. Use the identical measurement drill because the diameter of the screw - 4mm. Remove the duvet. Grab the screw with a couple of pliers and twist out the remainder screw.