How to Extract Stuck Screws.

Here's a guide to un-sticking stuck fasteners.

Imagine this: You're doing the first tune-up on your newly acquired bike. To get the oil filter cover off you need to remove three cross-head screws. You apply your trusty $1.89 K-Mart screwdriver to the first screw, and turn. The screwdriver slips out, so you try again, pushing harder. It slips out again, rounding the screw head a little. But you've got your trusty Vice-Grips in the tool box, so you clamp them onto the screwdriver's shank and really bear down on the screwdriver... this time stripping the head completely. Arrrgh!

If you've worked on bikes at all you're probably nodding your head right about now, saying "yeah, I did something like that." Bikes today have higher-quality fasteners than they did 10 or 20 years ago, but still the various forces of entropy conspire to stick fasteners together a little stronger than they're designed for. If you've worked on bikes at all you're probably nodding your head right about now, saying "yeah, I did something like that."
Here's a guide to un-sticking stuck fasteners. If you've worked on bikes at all you're probably nodding your head right about now, saying "yeah, I did something like that."

Impact Driver
The best remedy for a stuck screw, or one whose head has been stripped, is the impact screwdriver. An impact screwdriver is essentially two weights held apart by a spring. The bottom one holds screwdriver bits. You smack the top one with a hammer. In between them is a spring and a circular ramp. The ramp makes the bottom weight with the bit in it turn. So when you hit the top weight, giving it momentum, it compresses the spring and hits the ramp which turns the screwdriver-bit-holding bottom weight. The beauty of the design is that the force you impart to the impact wrench by hitting it with the hammer is forced into the screw, helping the screwdriver bit bite into the screw head (or what's left of it). Most impact drivers will let you set them for left and right turning, to loosen or tighten screws.

The high-quality, hardened screwdriver bits that come with impact drivers usually fit the screw heads much better than even the best screwdrivers, which helps all by itself. So at the first sign of a recalcitrant Phillips head screw, reach for the impact driver! Impact drivers are commonly available and cost about 15 (American) dollars - check your local auto supply store.

Some cheap impact drivers have (relatively) stiff springs which require a heavy hammer to compress and get the ramps to turn the bit. Be warned that the force needed may be damaging to the assembly in which the screw is stuck, or may be difficult to counteract on an awkward piece. These impact drivers can benefit from being disassembled and having the springs shortened slightly (no more than 25 percent) to reduce the spring preload. After this modification the driver will not require as much force but may not work quite as well on really badly buggered screws.


Screw Extractor

When an impact driver can't remove a screw, or there's not enough of the screw protruding to grip, the next step is to drill off the screw's head and then use a screw extractor.

Screw extractor bits are made of very hard metal, so they are very brittle. It is very easy to break one off inside the screw. When that happens you are screwed...

A screw extractor is a very hard reverse-thread bit. You drill a hole into the screw, then carefully tap the proper extractor (which has a smaller initial diameter than the hole, and quickly flares out) into the hole, and use it to twist out what is left of the screw. The reverse flutes on the extractor cause it to bite harder into the metal of the screw as you put more force on it. Screw extractor bits are made of very hard metal, so they are very brittle. It is very easy to break one off inside the screw. When that happens you are screwed (sorry for the pun)- the extractor metal is harder than any drill bit, so you can't drill it out. The only recourse will be EDM (see below). To turn the extractor you should use a tap handle commonly used to turn threading taps. The screw extractor has a square end to fit into the tap handle. Using a regular wrench to turn the extractor is almost guaranteed to break it.

You should be very careful when drilling the hole in the screw. Obviously you don't want to drill into the material surrounding the screw, so be careful to line up the drill in the center of the screw. Use a drill press if you have one and the part is small enough that you can set it up solidly in the press. Drill slowly and stop often to check your progress. Drill a small pilot-hole first, using a punch to mark the spot before you start drilling.


Many times, drilling the hole in the screw will be enough to loosen it as the pressure is released, and you will be able to ease it out with little force on the extractor.


Drilling out screws


If that doesn't work, the next option, depending on the design of the cover that the screw holds down, is to drill out the screw head completely. Often times, removing the head of the screw releases the pressure of holding two parts together, and again will come out easily, unless of course it is rusted or frozen. In this case, if there is enough of the screw-shank sticking out after the cover's removed to let you file flats on it, use locking pliers to turn it.

Use a drill bit that is just large enough to take out the screw's head; it should be slightly larger than the shank of the screw so that when you drill through the head and get to the shank the head will come completely off. Obviously you need to have the hole exactly centered to do this without touching the surrounding material. If the buggered screw head is irregular this is difficult to do with a hand-held drill, as the drill will catch on the protruding bits and go off-center. You may be able to even out the screw head with a small file or a pointed grinding-stone in a dremel-tool (small high-speed hand-held grinder) then center-punch and drill.

Other Methods

Sometimes you can grasp the head of a screw with a pair of locking pliers and use their better grip to get enough torque on it to get it started. Or you can carefully file flats in what's left of the head, or on the threaded portion itself if it protrudes.T his obviously will require that the screw be replaced after it's removed, but it can help you to get it out so it can be replaced.

A couple of tricks for short screws: you can heat the screw with a torch. Often heating and cooling threads loosens them. If the screw is held in with a locking agent (e.g."LockTite") heat will destroy the bond and make it easier to remove. You need to be able to heat the threaded part of the screw; long screws with their threads deep inside the engine cases will not be affected by heating the screw head. Don't use anything stronger than a propane torch; an oxy-acetylene torch can burn through a set of aluminum cases in short order. Even with a propane torch, don't hold the torch on one section of the cases for more than a second, play it around a small area near the screw. Don't heat the cases too hot; hot enough to sizzle when a drop of water is put on them is hot enough.

A second trick is to use a dremel-tool to grind a flat on the periphery of the screw head, and then use a hammer and punch on the flat to turn the screw. This works on the tiny short screws sometimes used to hold gear box bearings into crank cases.

Stuck Nuts and Bolts

Bolts get stuck just like screws do, the difference is that bolt heads are usually sturdier so rounding off the head is not so much of a problem.

If you do round off a bolt head the methods to remove it are similar to the ones used to remove screws.

However the usual problem is that you just can't turn the bolt. The first thing to try is more leverage. If you're using a sturdy breaker-bar for sockets you can slip a length of water pipe over it to use as a cheater bar. A regular ratchet handle isn't up to the stress that you can generate this way. For nuts and bolts over 13mm you should use a 1/2" drive bar.

With a long cheater bar the limit to how much force you can apply is determined by what it takes to move the entire assembly. For instance to remove the rotor nut from an RZ350 crankshaft, a four foot cheater bar is required. If the engine is out of the bike you will need to strap it to your workbench and get a friend to help hold it and the workbench in place.

Impact Wrench

One caution, an impact wrench shouldn't be used to tighten nuts or bolts on motorcycles (except perhaps those RZ350 rotor nuts) as their torque settings, if they exist at all, are very approximate. It's easy to over-tighten a nut or bolt with an impact wrench.
An alternative to cheater bars is an impact wrench. These are available in both air-driven and electric models. The air-driven type is what the local car tire shop uses to remove car wheels. Impact wrenches work by using air or an electric motor to turn a rotating weight which slams repeatedly into a lever connected to the socket drive. Since they hammer the socket drive around a small step at a time, there is very little torque reaction, so it doesn't take much effort to prevent the shaft that the nut or bolt is attached to from turning. Most 1/2 inch drive impact wrenches can deliver 75 ft-lbs of torque or more. Air impact wrenches cost from 35 dollars up and require an air compressor. Electric impact wrenches cost more, they start at 80 dollars, but do not require air. They're useful for racers who compete at tracks with electrical outlets in the pit area.

One caution, an impact wrench shouldn't be used to tighten nuts or bolts on motorcycles (except perhaps those RZ350 rotor nuts) as their torque settings, if they exist at all, are very approximate. It's easy to over-tighten a nut or bolt with an impact wrench.

Desperate Measures

Another way to remove stuck nuts is to use a nut splitter. It's not as painful as it sounds. A nut splitter is a steel collar which slips around the nut. One side of the collar has a hard steel wedge which is driven into the nut to split it by turning a bolt on the side of the collar. These are only needed to remove really badly rusted nuts, usually on the under carriage of cars. Their use on motorcycles is rare, but if you have a nut that's hopeless and can't be removed any other way you should be aware that this tool exists.

Another option is a small cutting wheel in a dremel-tool. It will spray hot sparks and bits of grit all over, and will generate a lot of heat, but it can cut through the ugliest frozen nut... if you can get to it. If it's buried deep inside aluminum cases, there's one last possibility: EDM.

EDM

The Option of Last Resort is Electrical-Discharge Machining.

EDM can be used to electrically machine a hopelessly stuck steel bolt or screw out of aluminum cases or heads. The equipment is not generally available in the home workshop; you will need to take the entire assembly to a shop that does EDM. Certain hard-core home shop fanatics have constructed home EDM machines of varying capacities, and plans for them do exist, but given the infrequent usage for motorcycle mechanics it is more economical to farm out the work.

EDM, also called spark erosion, uses an electric spark to remove metal. An electrode is moved close to the work piece and sparks are repeatedly struck between the two. The gap has to be controlled very closely, so EDM machines are electrically controlled. EDM can machine to fine tolerances, but the closer the tolerance, the slower the machining.

EDM is becoming more popular and available. If you've broken off a stud inside your cases, it might cost 50 dollars to get someone to use EDM to remove it. You will probably need to drill out the remains of the stud and use a thread insert ("heli coil") in that hole, but if it saves a 500-dollar set of crank cases you're still way ahead.

How to Lower a cruiser Motorcycle

How to Lower a Motorcycle

How to lower the seat height and profile of a cruiser motorcycle by shortening the suspension. But watch out below! From the June 2001 issue of Motorcycle Cruiser magazine.By Jerry Smith.

To some, a cruiser is a motorcycle. To others, it's a blank canvas. Often, the ink on the sales contract is barely dry before this second group bellies up to the parts counter and orders an armload of aftermarket goodies to make their new bikes look shinier, sound better and go faster. Most of these modifications won't make a bike any easier to ride, and a few actually make it harder. There's one increasingly common custom touch, however, that not only adds style, but also can make a bike easier to handle, at least if you have trouble reaching the ground.

Lowering a bike doesn't just give it that long, low custom look, it also allows shorter riders to put their feet flat on the pavement at stoplights. And if you've ever found yourself on a too-tall bike at a slippery intersection, you might be willing to trade in all the shiny chrome in the world for secure footing. (Though we know very short riders who have adopted to tall motorcycles.) "Probably more guys are after the look," says Progressive Suspension's Larry Langley, who estimates the ratio is approximately 60:40 in favor of lowering for style. "But more and more vertically challenged riders are doing it these days, too."

Regardless of your reason for lowering your bike, it's not a task to be taken lightly, and if you're unsure about the dynamics of this type of modification, consult a suspension specialist to avoid safety problems. Over the years, countless bikes have been lowered by backyard mechanics who took a hacksaw to the fork springs and bolted on a set of cheap lowering blocks to the rear shocks. Most of the perpetrators of such hatchet-jobs were happy with their work—until they rode it for the first time, and discovered that, in addition to cool-looking, the bike had become ill-handling, uncomfortable and unsafe. Langley gave us some guidelines for doing the job right, along with a few caveats to keep in mind, even if all goes well.

Lowering the Front End

"First, as a general rule, never lower the front without lowering the rear," Langley says. "You can lower the rear without lowering the front, and what it does is give the bike more of a chopper effect. But if you just lower the front, you unbalance the bike the wrong way." Many bikes can be lowered by approximately an inch in the front fairly easily by modifying or removing the stock preload spacer. Some bikes come with preload spacers that compress the fork springs an inch or more when the fork is unloaded. Shortening the spacer drops the front end of a bike an amount roughly equal to what you removed from the spacer. But be careful not to go beyond the point where there is minimal pressure on the spring when the suspension is fully extended. If you go beyond this point, your bike will be effectively springless when the front extends completely, as when the front wheel drops into a dip in the road at speed. Not a pretty scenario.

If you want to lower your front end more than an inch, says Langley, probably you'll have to do it mechanically. "What we do is put a spacer, which is really a short spring, under the damper rod. That fools the fork into thinking it's shorter, and doesn't let it come back up to full extension." If the fork has a preload spacer on top of the spring, you also might have to remove or shorten it, or the spring will be too compressed when the fork is at rest. Depending on the bike, you may need shorter main fork springs because you've taken up so much travel that the springs will not let the fork compress fully before the coils contact each other, preventing the fork from compressing.

Cartridge Forks

The preceding methods work for any bike that has damper-rod suspension. "If it has cartridge forks," Langley says, "it's a much bigger problem. For example, we don't even make a lowering kit for the [Honda] Valkyrie, which has a cartridge in one leg and a dummy cartridge in the other." A cartridge is like a rear shock internally. Consequently, there's not an easy way to shorten it. If the design allows, you can slide the forks up in the triple trees; make sure, however, the fender doesn't hit the triple tree when you compress the fork completely, as when hitting a large, sharp bump.

Lowering the Rear End

If you only intend to lower one end of a bike, the rear end is the better choice. And it's all some riders need, since lowering the rear end also lowers the seat substantially, making it easier to flat-foot a bike at stops. The backyard crowd has a quick fix for this—lowering blocks, which are machined spacers that relocate the rear shock's bottom mounting point several inches to the rear. They're cheap, easy to install and their net effect is to lower the back of the bike. But there's another consequence of using lowering blocks which is not so obvious—they drastically change the rear shocks' lever ratios.

Lever Ratio

A shock's lever ratio is determined by the angle at which it's mounted. To better understand this concept, picture a bike's rear suspension, including the swingarm pivot, the rear shock's lower mount and the rear axle. Next, imagine the rear wheel moving though its travel, which describes an arc, and draw that arc. The distance the rear axle travels typically will be farther than the distance traveled by the shock's lower mount. At the extreme, the shock might be moving two inches, and the rear wheel four inches.

This disparity can have unintended consequences if you decide that in order to lower your bike an inch, you only need to fit your shocks an inch shorter than stock. "On a bike like a Valkyrie, which has a 1.5:1 lever ratio, a one inch shorter shock will lower the bike an inch and a half," Langley says. Most bikes have a lever ratio greater than 1:1, and on a single-shock bike such as Yamaha's Road Star, the lever ratio may be as high as 3:1. "The only bikes that have close to 1:1 lever ratios are Harley FLHs," Langley points out.

The drastic change in lever ratio that results from using lowering blocks essentially makes the shock stiffer, reducing ride comfort. So why not just go to a salvage yard and yank some shorter shocks off a wreck? Langley warns, "Shocks are engineered for a particular model. For example, a [Harley-Davidson] Dyna Glide shock will not work on a Sportster because the lever ratio is different. The shocks on a Dyna are moved way up, and they have heavy damping and 300 pound springs. The spring on the Sportster shock is a 100-pound spring and the damping is lighter. Switch them and they'll be either too soft or too hard on the wrong bike. The spring has to be right, and the damping has to match the spring. You have to buy by application, not length."

Effects on Handling

Even if you lower your bike by the book, handling can be affected to some degree. "When you lower a bike, you also lower its center of gravity, so it'll handle a bit better in certain circumstances," says Langley. "The negative is that your initial ground clearance is decreased. Things you used to clear, like curbs or speed bumps, might now be a problem."

And that's not the only thing you'll notice during your first ride on your just-lowered bike. You've given up travel, so your comfort will suffer. As Langley puts it, "The more you lower it, the more ride quality and comfort suffer. Two inches of travel won't do the same job as four inches of travel." Why? The springs must be stiffer to keep you from bottoming out, and the shocks usually need heavier damping to match the heavier springs, which leads to compromises that might force you to re- consider lowering in the first place.

Cornering and Braking


Here is the major drawback of lowering your bike. It will no longer lean over as far as it did before, which could get you into trouble when a corner tightens up or you mis-judge its arc or if you simply have to tighten your line to avoid an obstacle.

If ground clearance is affected, how about cornering clearance? Common sense tells you a bike's lean angle should be reduced, too. While Langley (and most manufacturers of these kits) says lowering a bike seldom reduced enough to make a difference, practical experience has shown the Motorcycle Cruiser staff that cornering clearance is noticeably altered. If you drag pegs occasionally at the stock ride height, you will do so more frequently if the bike is lowered. Also, if your bike tends to drag solid mounted parts, such as its pipe or sidestand, lowering is not for you.

Braking is a performance category where few riders will notice a difference. Theoretically, lowering a bike should result in less forward weight transfer under braking. But cruisers' long wheelbases should make the difference negligible. However, if you find the fork bottoming out under braking, consider a set of progressive rate springs to stiffen up the front end in the bottom of its travel. The shorter travel may also make the bike chatter more over bumps under braking.

Load

So far, we've seen that when you lower a bike you give away some ride quality. Langley says you also should be prepared to give up some load capacity: "You can't make a bike low and have the same load capacity. That's because you lower the bike at the expense of suspension travel." The reduced travel means the bike can bottom out easier. Those planning on extended two-up riding should forego lowering. If you want to make your cruiser a show bike and troll Sturgis, go for it. But if you want to pack some gear and a passenger and ride across the country on a lowered bike, you're not going to be happy.

There's one more way to lower a bike, which is to fit smaller wheels, lower-profile tires, or both. (Of course, you can simple cut the seat down by removing foam or replace it with a thinner saddle.) The wheel change approach is an option that seems appealing, especially with the advent of a wide variety of aftermarket wheels currently available for metric cruisers. Today, you don't just see Harley customs sporting enormous rear tires and low, wide wheels at bike shows. While that setup might lower the bike, Langley suggests you bear in mind that most of those customs aren't ridden much, if at all. "Now you're into an area that drastically changes geometry and how the bike handles," he says. "You'd better really know what you're doing." We recommend changes of this type be made carefully—with the guidance of builders who have performed this type of modification before.

The Lowdown

Langley offers some final thoughts on lowering: "The more you lower it, the more ride quality suffers. That's the first thing I tell anyone considering lowering a bike. What I generally recommend is going an inch lower front and rear, so you'll still have enough travel to give [yourself] a good ride. That's a pretty good compromise, but anything over that and you're giving up a good ride."

Regardless of whether you want to lower your bike for good looks or peace of mind, resist the quick-and-dirty fix, and remember that lowering unavoidably involves compromises, no matter what some backyard customizers say. You can live more easily with those compromises if you do the job right and don't take it too far. Just don't forget the idea is to get down...not hit rock bottom.