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The American Motorcyclist Association • www.AMADirectlink.com

Posted December 20, 2005 Email | Print

Smooth operator

Forks are easy to ignore on old rat bikes. For one thing, particularly with fork boots installed, everything is hidden from view. Leaky seals? Out of sight, out of mind, right?

Wrong.

Fresh oil is important because it is the movement of that oil that meters the compression and rebound of your forks. Without the damping process, the fork spring would compress and rebound unencumbered, like that on a pogo stick. If you don’t want your dirt bike to handle like a pogo stick, keep the fork oil fresh.

Even at slow riding speeds, broken-down, contaminated or too-little oil can negatively affect fork operation. And if you hit a sharp-edged rock or rut, it can be downright dangerous.

The extra plushness and proper rebound action that you get with a fork oil change makes the ordeal of changing it worth it, especially when what’s squishing around in the bottom of your fork tubes can look more like tooth paste than high-viscosity dino juice after 20 years.

Not every bike will be the same as my XT, of course, but in general the steps for getting the old stuff out and the new stuff in are pretty simple.

On the XT, there are two ways to drain the old oil: one with the forks mounted and one with the fork tubes off.

If the forks are still mounted, with a strategically placed oil pan, remove the drain plug at the bottom of the fork tubes. Oil will start draining out. Pump the forks a few times and let it sit for awhile to make sure it’s as empty as it’s going to get.

Fork oil drain screw.

If the forks are off the bike, you can be even more thorough.

On the XT, there is an internal snap-ring that holds the stopper for the fork spring. As is usual with old stuff that has seen some harsh conditions, the snap-ring on the XT’s forks is rusted and stuck. I loosen that with a few swift blows with a ball peen hammer and wooden rod.

Ring rust is bad.

Then, I compress the spring by pushing on the spring stopper. It was very hard to work a screwdriver under the rusted snap ring with one hand holding down the spring stopper. On my dad’s suggestion, I clamp a pair of needle-nosed vice grips around the top rim of the upper fork tube. This holds the stopper low enough for me to pry out the snap-ring.

Ready for removal.

With the snap-ring out, the stopper and spring slide out of the fork tube. I can then simply pour the oil out of the top of the fork tube and replace it with new stuff. For extra bottoming resistance, I squeeze in a few extra ccs over the recommended 168cc of oil, using a relatively heavy 15-weight Bel-Ray.

Then, I drop in the spring, install the stopper (cleaned and with a new o-ring seal), compress the spring with the vice-grip trick, and install a new snap-ring. New fork boots and plastic end caps go on, and the forks are ready to install.

Project F, Part 3: Decision time — replace it, repair it, or just live with it

by James Holter

Before Dr. Frankenstein could assemble his monster, he had to disassemble the various “donors” to the project. My “Frankenbike” is no different. In Part 2, my partner in grime, Hollywood Joe, and I field tested the 1981 Yamaha XT250, and proved it worthy of this project’s limited resources. In Part 3, I’ll take it to pieces.

Like the Phoenix, the XT will rise from the ruins of its former existence to glorious new horizons.

Or, something like that.

Before I get any vintage enthusiasts excited out there, let’s be clear: I have no intentions of restoring the XT in the religious sense. The goal is to strip it down to its woods-riding essentials, freshen up the moving parts and other “disposables,” such as brakes, tires, bearings, etc., and get it back on the trail. And to do so as cheaply as possible.

This is a good time to share a few words of wisdom about the financial soundness of such a project: You don’t fix up rat bikes for profit. Consider the XT. It was free (donated by District 17 hare scrambles racer and AMA member Brent Pierce), and forget “woods worthy.” Just getting it “woods capable” is going to cost, in parts alone, roughly what it might command on the used market as a complete bike.

Face it. It’s tough to come out one dime ahead fixing up a free dirtbike, let alone one that actually costs you money. Figure in your time investment, and unless you’re restoring something truly classic, or certain AHRMA class-legal vintage racers, you’re playing a fool’s game.

That said, rat bike repair can be immensely enjoyable, fun and educational. Plus, for most of us, the feeling of accomplishment after one ride on your woods-capable rat bike makes it all worthwhile. If nothing else, while your neighbor’s garage is full of broken weed-eaters, bent shovels and tangled water hoses, yours is full of all that junk plus some really cool old dirtbike stuff.

Breakdown

As for the actual process of stripping down an old bike, what’s there to say? If you can turn a wrench, you’re pretty much an expert. As far as universal advice goes: Stay organized.

It’s a good idea to use labeled freezer bags for the many and sundry screws, bolts, brackets and grommets. At the very least, place the parts in strategically oriented piles on your workbench.

Any system will make reassembly considerably faster than if you have to dig the bits from the bottom of a big red box, such as the old suitcase I scooped random handfuls into in preparation for a move 500 miles across two state lines — a system that wouldn’t haven’t been quite so bad if my wife hadn’t “sorted” everything that was left.

But that’s OK. I’m supposed to be a pro at this, right?

Right now, we have bigger issues to tackle, as in what needs done to make my XT rideable again. After picking apart and examining every square inch of the XT for wants, needs and desires. Here’s what I find out.

Must be replaced:	Should be replaced:
Sprockets. Worn.	Handlebars, grips, levers. Modern is better.
Chain. Stretched.	Front and rear fender. Cheap bling.
Brake pads. Done for.	Clutch cable. Gummed up and bent.
Tires and tubes. Bald and cracked.	Front brake cable. Ditto.
Wheel bearings and seals. Rough.
Air box and air filter. Non-existent.
Ignition cover. Non-existent.
Skid plate. Non-existent.
Shift lever. Non-existent.
Clutch and brake levers. Non-existent.
Front number plate. To replace the non-working headlight.
Spark plug. The XS1100 plug isn’t spec.
Oil filter. Gummed up.
Fork boots. Ripped.

Must be done:	Should be done:
Clean the carburetor.	Change the fork oil.
Clean off 24 years of dirt and grime.	Adjust the valves and cam chain tensioner.
	Apply grease, anti-seize or locking compound where appropriate.
	Paint the frame, exhaust, engine, fuel tank, etc.

While I’m providing much of the labor for this project, one item is out of my hands. As mentioned in Part 2, riding buddy Hollywood Joe is providing the custom paint job for the fuel tank and will provide a full report on his work later in this series.

As for my stuff, yeah, there are a few things missing from the to-do list. For example, in addition to adjusting them, I should lap (or replace) the valves and valve seats, and probably replace the valve springs. It also would be a good idea to rebuild the shock; however, old Yamaha monoshocks typically are not serviceable.

Everything that I don’t plan to replace will get dealt with on an as-needed basis. So, if the clutch slips or drags, I’ll dig into it. If not, I’ll be happy.

However, I’m not even to the rebuilding process yet, let alone to the first test ride. First, I need to make these rust-scarred, grime-coated goods spread out before me look new again.

And what if I can’t?

If nothing else, at least my garage will be that much cooler than my neighbor’s.

Project F, Part 1: Bringing a "free" 24-year-old XT250 back to life
Project F, Part 2: Stripping and field-testing the XT250
Project F, Part 3: Decision time — replace it, repair it, or live with it
Project F, Part 4: Making old, grimy things shiny again
Project F, Part 5: Sticking with the plan for the payoff at the end
Project F, Part 6: Work in Progress