Folks...this post has been a "sticky note" on one of the boards up here in Canada for a long time. Excellent advice to anyone looking to buy a new bike. Hope this helps some of you, and provides a refresher for the rest of us.
FIRST THINGS FIRST
* Resist the temptation to buy the first bike you see. Look at a few of them to get a better idea of the used bike market/options before you buy one.
* Bring a friend to help you stick to your guns, or to help you load your new bikes onto a truck, or as ballast in case the bike has a centerstand and you wish to inspect the front wheel. Bike-savvy friends may also notice things that you forgot to check. Make sure they also read this guide ahead of time.
* Bring a flashlight to aid inspection. Even in daylight.
* Request that the owner not have the bike warmed up when you get there, but tell him/her to make sure that the bike will start. If the owner asks why, tell them that you want to test the bike's ability to start when cold. (It's a lot easier for engines to start when pre-warmed.)
* You needn't follow these instructions in any particular order, or even follow them at all, but if you are going to read them, you should probably do so before you get to the seller's house. If you're new to motorcycling, you'll probably find a lot of the terminology complicated. Try studying some of the "related photos" and RECOMMENDED READING listed below. And as noted previously, try to bring a friend, particularly one who knows bikes.
* Bring riding gear in case the seller will let you test ride the bike. (If you're new to motorcycling and don't have any gear yet, perhaps the bike-savvy friend accompanying you will be kind enough to bring his/her gear, and do a test ride for you.)
* You'll have to go through and carefully inspect used bikes being sold by dealerships, too, since many dealerships take used bikes as trade-ins, make minimal (if any) repairs, and mark the bikes up way over "blue book" value. It's up to you to find defects (and to know what the used bike's real value is!!) to get these vultures back down to a reasonable price. Think of it as a treasure hunt -- you're looking for the hidden secrets that will save you money.
* As a general rule of thumb, when work needs to be done to repair a problem with the bike, most dealerships charge around $50/hour for labor, possibly more for European marques (Ducati, BMW, Triumph, etc.)
* In the text below, "left" and "right" refer to the rider's left and right sides when sitting on the bike.
* If you aren't really experienced with bikes, do some practice inspections! Find a couple of friends with bikes, and, pretending that you're at a seller's house inspecting a used bike, go over a couple of bikes in minute detail. You'll learn a lot about how bikes are put together, and you might even find some things that your friends missed. Take notes while you're doing the inspections, and go over your findings with your friends after each inspection.
* When you end up buying a bike, make sure you get everything related to the bike: the key and any spares that the seller has, any free/included spare parts, the owner's manual and service manual, etc. Having to go back to the seller to get stuff you should have remembered the first time is a pain. And you may find the seller far less accommodating after you've paid for the thing.
OVERALL APPEARANCE
* Does the bike look nasty? Cracks and scratches all over the thing? [1] Appearance can be deceiving, but it should give you some indication of the general condition beyond what you can see.
* Do fasteners look stripped or gouged? Is everything kinda loose and ill-fitting? You don't need to be a mechanic to tell when the person has mangled something on the bike. The bike should also be cosmetically symmetrical. (Not "symmetrical" like "are there brake discs on both sides of the front wheel", but "symmetrical" as in, "are the mirrors, the plastic, the handlebars, etc. symmetrical, or do they seem to be askew?" [2]) Step back and sight down the centerline of the bike. If something looks obviously wrong (the mirrors stick out a different angles, the windscreen is tilted, the turn-signal stalks are ripped off the fairing, etc.), the bike has probably been crashed or fell over hard.
* Basically, try to answer the question: "How does the overall cosmetic appearance of this bike affect how much I want to pay for it?"
HAS IT BEEN CRASHED?
* Look for: deep parallel scratches on engine cases and on plastic (particularly above footpeg-level); a different/non-standard paint job (the owner might have repainted it to hide damage); paint or metal ground off the ends of the handlebars [1], or off the balls on the ends of the clutch/brake levers; dents in the gas tank where the handlebars may have smashed into it during a crash [2]; dents and deep/parallel scratches in exhaust pipes; turn-signal stalks bent or ripped off; cracks in plastic bodywork obscured by stickers [3]. (Aftermarket stickers are sometimes used to cover defects -- beware!)
* Sometimes brake and clutch levers will be bent in a crash and replaced with a lever that's a different color than the other side, or a slightly different style than the other side, or it'll be hammered back into shape so it doesn't look obviously bent. (In the latter case, look for thin cracks in the anodizing or clear coats of levers... it'll look something like a spider web of hairline cracks.) Also look for bent or cracked mirrors, or mirrors replaced with mirrors of a different type. Both are signs that the bike has been down. Not necessarily crashed, but at least tipped over. Check carefully.
* Sometimes a crash will twist the front forks. Sit on the bike, sight down the forks, and see if they're at all twisted or bent. (Twisted is pretty cheap and easy to fix, bent is not, but either ought to be a warning sign to check extra-carefully for other damage.) If you get a chance to test ride the bike, get the bike going straight, and take a quick look down at the bars to make sure they're pointed straight -- if they aren't, the front has probably been twisted in a crash.
* Non-parallel scratches and shallow chips tend to indicate a tip-over rather than a crash at speed. (Crashes, of course, tend to do more damage -- tip-overs rarely do more than minor cosmetic damage.)
* You may come across a bike that has horizontal scratches on its lower plastic and metal parts... this isn't necessarily a crashed bike, it could just be that the owner was an enthusiastic rider that leaned the bike way over when turning. Ask the owner about the origin of the scratches, but unless you see evidence of a crash, it's probably just evidence of an enthusiastic owner. Deep/parallel scratches above footpeg-level are something to be concerned about, though.
* Crashes can cause bodywork problems for two reasons. Besides scratching and cracking the bodywork, crashes can bend the bodywork's mounting brackets and break mounting tabs [4]. Check to make sure that bodywork pieces that fit together do so easily and have an even seam where pieces come together. And check to make sure that the bodywork isn't loose, either because mounting tabs were broken off or because aftermarket fairings might not mount up as well as the stock stuff.
HAS IT BEEN RACED/ABUSED?
* Racing puts tremendous stress on machinery. You may or may not want to buy a bike that's been raced (the price ought to be way lower than it would be otherwise), but you should definitely try to find out if it has or hasn't been raced, so you can adjust the price accordingly if need be.
* Look for holes drilled through the heads of bolts [1], which racers use to safety-wire bolts in place. Check: front brake caliper mounting bolts [1], exhaust pipe bolts, engine case bolts, oil/water drain bolts [2], etc. The holes will be small, about 1/16", and should not be confused with the 1/8"-3/16" holes and castellated nuts that are often used to hold axle nuts on axles with cotter pins. Safety-wire ends can be extremely sharp -- don't cut yourself.
* Tires with roughed up edges, covered with ragged strips of balled-up rubber is a sure sign that the bike has been raced. [3] [4] If the rear tire is completely flat in the middle but looks practically new on the sides, the owner may have performed a burn-out with them. (Not necessarily damaging to anything other than the rear tire, but a possible signal that the owner hasn't taken good care of the machine.) In rare instances, frazzled/ragged edges may be there because the bike's owner bought "take-offs" (used race tires) from a racer, and not because the bike itself was raced. But be very suspicious.
* Also look for heavy-duty aftermarket engine covers [5] -- made by NRC, Factory, Traksport, Yoshimura, etc. Many racing organizations require them, so they're a decent tip-off that the bike has been raced. They tend to be cheaper than the OEM case covers they replace, however, so sometimes they're used to replace crash-damaged case covers. By themselves, they aren't proof that a bike has been crashed or raced, but look around carefully for other tell-tale signs.
* Look at the under-side of the rear fender. (You may need a flashlight for this.) If you see a thick streak of balled up & flung-off rubber on the inside of the fender, that's a good sign that the owner has done a burn-out on the bike. Burn-outs mostly damage the tire, but could be indicative of other abuse. Be alert.
* Check the frame for cracks, usually along welds. Check around the steering head, around the engine mounts, and, if possible, welds in the front fairing bracket and rear subframe. ("If possible" because these brackets may well be covered by fairings on many models.)
BIKE-SPECIFIC
* Some models have specific problems that you should be aware of. Ask dealerships, bike-savvy friends, etc. Read magazine reviews. Examples: many Kawasaki EX500's (and some other older Kawasaki sportbikes) have problems where they'll pop out of second gear while engine-braking. Some older SOHC (single overhead cam -- an engine design) Hondas had lubrication problems. Learn as much as you can about the models you're interested in. (Try old bike magazines, grizzled old bikers, etc.)
* Here are two sites that do searches and provide reprints from magazines:
o
http://www.mcreports.com/
o
http://home.earthlink.net/~motoinfo/motoinfo.html
BRAKES
* Put the bike in neutral. Roll the bike forward, gently apply the front brakes*. They should engage (and the lever should move) smoothly. (Though you may hear a click as the brake-light switch engages.) Now release the brake lever and roll the bike... Are the brakes off, or are they dragging? (They should be off.) If not, the brake calipers need work. Stand in front of the bike with the bike in neutral. Grab the front brake lever and squeeze it hard against the handlebar. As you're doing this, try to drag the bike forward by the handlebars. (You may want someone behind the bike to stabilize it.) Do the brakes prevent the front wheel from moving? They should.
* *=If you squeeze the front brake lever and it comes all the way back to the bar without much resistance, something's very wrong. Try adjusting the lever, if you know how (look for a little dial near the pivot). If this doesn't fix it, or you have to pump the brakes a lot to get them to work, the system is either empty, full of air bubbles, or something is amiss in the master cylinder or caliper. Check to make sure that there's adequate pad thickness, and make sure you get a professional mechanic to inspect the brakes before you try riding the bike. At the very least, the system needs to be bled. About $5 of brake fluid and half an hour of labor.
* Rear brake... roll the bike forward, use the rear brake to stop the bike. It should also engage smoothly. If the rear brake is a drum brake (no exposed brake rotor), is the wear indicator needle inside or outside the "usable range" indicator when the brakes are applied? Outside, of course, means the brakes are worn out.
* Some states have a mandatory safety inspection. If yours does, they'll probably require that both front and back brake levers (separately and together) illuminate the brake light. If one does and the other doesn't, you probably need a new switch (around $25?) or a switch adjustment. If both don't, you probably just need a new bulb (around $1.)
* Check remaining brake pad material. There should be at least 1/8" of brake pad material on each brake pad. For bikes with disc brakes, get in front of the bike and look into the calipers, on either side of the rotor(s). A flashlight might help here, even in daylight. The pads are the raised parts that directly contact the brake disc. If the bike has a disc brake in back, do the same type of inspection with the rear brake pads.
* Disc brakes continued: rotors should be a certain minimum thickness and shouldn't vary more than a certain amount when spun. This kind of information will be in the service manual. As a general rule of thumb, rotors should be a minimum of 4mm, and warpage should be less than .012". (FWIW, even warpage of .020" probably won't show up in the form of lever-pulsing at speeds below 45 mph.) If you don't have the right tools to test this, you'll probably need to rely on a test ride to spot a warped rotor -- unless it's so bad that you can see it with the naked eye. Even if you don't have the right tools, you can inspect the rotors for cracks, deep wear grooves and other damage.
* Brake fluid should be a very light amber. Darker than honey means it's time to replace the brake fluid. Not expensive, but possibly an indication that the owner hasn't followed the maintenance schedule. (Or maybe the bike has just sat for a long time.) The front brake fluid color and level should be easy to inspect through a sight glass in the front master cylinder or via marks on the translucent brake fluid reservoir. (Fluid level should be roughly in the middle of the sight glass or reservoir min/max range when the bike is on level ground and the steering is centered.) For bikes with disc brakes on the rear wheel, check the rear brake fluid as well -- sometimes visible under the seat/tailsection, sometimes visible through a hole cut in the tailsection or side fairings.
* Inspect the brake hoses for nicks, cuts, dry-rot, and leaks.
* New brake pads are around $25-30 per pair (each caliper has one pair, so a bike with two brake rotors in front = two calipers up front = two pairs of pads up front.) Brake rotors are usually around $150-250 each. Brake lines are about $80-150 new, but if you have to replace them, replace them with braided stainless-steel lines, which cost a lot less ($70-80 new) and offer better brake feel and less heat-induced expansion.
CLUTCH
* Ask the owner how many miles it's been since the clutch cable was changed*. Owners who keep close tabs on bike maintenance will know. That's a good sign. Most owners probably don't know. If there's a little slack in the clutch cable, and you can move the lever 5/8" or an inch or so before the cable goes taut (something like this), that probably just means that the cable adjuster needs a turn or two.
* Put the bike in first gear, squeeze the clutch all the way in, roll it forward. It should feel like neutral, with possibly a little more resistance**. Slowly let the clutch out and feel for the friction zone. Clutch engagement should be fairly smooth, not abrupt. Put the bike back in neutral.
* If the bike has high miles (30k mi +) ask if the clutch has been changed. Only about $100 + 1 hour of labor, unless you need a new clutch basket, then maybe $300 + 2 hours of labor. (You won't know until you get the clutch apart.)
* *=Some larger-bore bikes will have a hydraulic clutch instead of a cable-operated clutch. If this is the case, check fluid color and level through the master cylinder's sight glass. Fluid should be a very light amber, like the brake fluid, but both are pretty easy to change. The clutch master cylinder will be located on the left grip, much the way the front brake's master cylinder is located on the right grip. Hydraulically-actuated clutches may or may not be "wet" clutches. A "wet" clutch is bathed in oil; a "dry" clutch is not. It's hard to tell the difference just by looking at a bike, but as a general rule of thumb: Ducatis, BMWs and Moto-Guzzis use dry clutches, most other models use wet clutches.
* **=Wet clutches may tend to stick or drag a bit until the bike has warmed up and the clutch has spun a bit. This is often the case when the clutch hasn't been used in a while. Wait until the bike has really warmed up before you dismiss a potential acquisition for having an overly-sticky clutch.
GAS TANK
* Look for: dents as noted above [1]. Open it up, look for rust and/or loose sediment. Rust/sediment is bad -- it clogs carburators. Bikes with rusty tanks need to have the rust removed... drop the price $150 or so. You should open the tank up and see light-amber colored gas and bare metal. If you see a milky paint-like coating on the insides of the tank, the bike has had rust removed and the insides of the tank recoated. Make sure it runs -- sometimes this recoating can clog the fuel's path out of the tank. Many people swear by it, but I'd pay a little less for a bike with a tank that's been recoated.
o Exceptions: Some late-model bikes (e.g., recent Triumphs) have plastic gas tanks. It's normal for plastic gas tanks to be milky-white on the inside. Knock on the side of the tank to see if it's metal or plastic. Exceptions to exceptions: some bikes have metal tanks but have plastic tank covers, so when you knock on them, they'll sound like plastic, but they aren't. (Example: Yamaha FZR400's.) Your best bet is to look closely at the inside of the tank -- it should be fairly easy to tell whether or not you're looking at metal or plastic. Evaluate the tank's condition accordingly.
* Dark (coffee or tea-colored) gas has been sitting around for a long time. Not a good sign. Get it changed immediately, and anticipate needing a thorough fuel-system cleaning. (Around $5 of parts plus 2-3 hours of labor.)
* Make sure the lock in the gas cap is working. If it isn't, it'll probably cost $100-$200 to get a genuine OEM replacement cap with a lock that matches the ignition's.
SEAT
* Look for: tears in the vinyl cover [1]. New upholstery will cost around $100-150 from an auto/marine reupholstery place. (Check the yellow pages.) Seats with cracks and tears retain water and get your butt wet many days after the last rain. Highly annoying.
* Seats (or tailsections) typically use a locking release (like the gas cap) to prevent vandals from messing with your bike's electrical stuff. Make sure the release works with your key. If it doesn't, it'll probably cost around $80 + half an hour of labor to replace.
* Check to make sure the seat is stable and latches on snugly.
TIRES
* Ask the owner how many years and miles the tires have. The owner should know. (Bad sign if (s)he doesn't!) The tires should have at least 1/8" of tread left, preferably more. Squared-off tires, any signs of dry rot (really fine cracking -- look really close!), bald tires (no tread), knobby tires with worn down and rounded knobs... they all need to be changed. Tires worth using aren't cheap, but they're your sole source of traction, your only connection to the road -- do not cut corners here!
o Street/sport tires: $170-$300/pair
o Off-road tires: $100-$200/pair
* Make sure you read the section above called HAS IT BEEN RACED/ABUSED?, as it has some pointers about how to identify vehicle abuse based on tire wear.
* If you get a chance to ride the bike, seek out well-maintained (smooth) roads so you'll be able to tell if the tires have flat-spots or aren't balanced. (Both will cause perfectly rhythmic thumps or shaking that goes up and down as the speed goes up and down.)
* Tires should be changed at least every three years, though most serious riders would probably change them at least every other year. (That's in an ideal world; tires should be inspected regularly and replaced if they have damage that could cause handling problems or unexpected tire failures.)
* How do you know how old the tires are? All tires have an industry-standard dating code stamped on them. Look for digits stamped into the mold on the rubber sidewall of the tire. The date code for tires made prior to 2000 is: "WWY", where WW is two digits denoting the week of the year, and Y is the last digit of the year. A tire produced on May 30th (the 22nd week) of 1996 would be stamped 226. (A tire produced on May 30th of 1986 would also have a code of 226, but will probably have a ton of dry rot.)
* As of 2000, the date coding system has changed a bit. All tires are still required to be stamped with a DOT number on at least one sidewall, but now there's more data. Look for a code that starts with "DOT" and has up to 12 letters and numbers. The last four numbers are the date code in the format: "WWYY", where the WW two digits denote the week of manufacture, and the YY denotes the last two digits of the year. So a date code of "DOT913ACX3C2200" would have been manufactured in the 22nd week of '00. If the three/four digit stamp you found doesn't make sense with this scheme, you're not looking at the date code stamp. Keep in mind that both tires will have this date marking (possibly/probably different), and that tires should be replaced at least every third year, or whenever they have damage that threatens their integrity. (Punctures, cuts on the sidewall, excessive wear, dry rot, etc.) Frequent tire inspection could very well save your life.
* Dirt bike knobbies will tend to get worn on the forward edges of the knobs. Sharp knobs = good traction. (Nifty trick: If the leading edges of the knobs are worn (rounded off), but otherwise there's nothing wrong with the tires, you can unmount the tires and mount them backwards. Braking traction will suffer, but not too much. Note that this trick is only something that works on non-DOT off-road knobby tires; street tires should never be mounted backwards.)
* For information on a method of changing motorcycle tires at home, using a stand made with only $50 or so of parts, see:
o
http://www.clarity.net/~adam/tire-changing.html
ELECTRICAL & BATTERY
* Check to make sure the headlights (high/low) work. (On some bikes, the headlight won't come on until the engine does, so you may need to start the engine to test this.) Make sure the turn signals work, make very sure that the oil pressure light comes on when you turn on the ignition, and goes out when the engine starts! Make sure the neutral indicator light works. Make sure the starter works. Make sure the brake levers light up the brake light. Make sure the horn works.
* Basically, check all the switches as well as the signalling and instrument-cluster lights. (Bulbs are pretty cheap to replace.)
* A common way to steal a motorcycle is to hammer a large flat-head screwdriver into the ignition switch, and to start the bike by forcing (breaking) the lock. Check to make sure that the key works, that a wrong key (or screwdriver) doesn't work (careful not to break it yourself!), and for any possible internal damage. Ignition switches [1] can be a pain to replace, since they (obviously) match the same key profile of the seat release and gas cap release locks. There are some aftermarket units available, but you're better off going to a dealer to get OEM replacement parts. Probably around $200 + 1.5 hours of labor to replace.
* If the bike has one*, you should also test to make sure that the sidestand's engine cut-off is working. These are designed to prevent you from riding off with the sidestand down, taking a left turn, and getting flipped onto the ground. They work in different ways -- some prevent the engine from starting when the sidestand is down, some only prevent the engine from running when the sidestand is down and the bike is in gear (i.e., not neutral.) (Still others will let you put the bike in gear while the sidestand is down, simply killing the ignition as soon as you release the clutch, but these are kind of rare.) The design where ignition is killed when the bike is put into gear is a bit more dangerous to test than the design where it won't let the engine start with the sidestand down. You may want to start by putting the bike in neutral and trying to start the engine (once you know that it actually will start!) with the sidestand down. If it does start, we need to test to see if the safety has been removed or if it's just the other design... grab the clutch all the way in, hold the front brakes on hard, make sure the sidestand is down, and click the bike into first gear. If the engine dies, the sidestand cut-off switch works. If it continues running, the sidestand cut-off switch has been removed from the circuit. This might mean the bike has been raced, but it's more of a clue to check elsewhere for evidence of racing, since by itself it doesn't really mean anything. If the sidestand cut-off switch does not work as designed, you must be very careful (if you buy or test-ride the bike) not to ride off with the sidestand down! Now that we're done with this test, put the bike back into neutral, release the clutch, and kill the engine.
* *=Some bikes won't have such a cutoff. This includes certain Ducati models and a wide variety of older bikes. As noted above, if you buy a bike without a (working) sidestand cutoff, you'll need to be very careful to avoid riding off with the sidestand down.
* Make sure the kill switch on the right handgrip stops the engine when it's running. (Dirt bikes will have a kill button on the left handgrip.)
* Batteries are almost always located underneath the seat, though some modern V-twin sportbikes locate it beside the engine, and many dirt bikes and older standard bikes locate it behind a plastic side cover below (or below and slightly behind) the seat.
* Batteries are very hard to test without the appropriate tools, and even then they're kind of mysterious and unpredictable. For our purposes, if the battery starts the bike, it's good. If it doesn't, $50 to replace. Without hearing "good" batteries, it's hard to tell what "good" sounds like, but if the starter's cranking is obviously weak, that's probably a good indication that the battery is too. As noted below (in ENGINE/FLUIDS/CARBURATORS), warm bikes start much easier, so take that into account when making a subjective evaluation of the cranking sound.
* If the bike doesn't have an electric starter (i.e., it's a kick-start), there's no good way to test the battery without examining the lead plates for white sulfide deposits (bad) and checking the specific gravity of the acid with a battery hydrometer. Most auto parts places should carry those; just make sure you get one with a long, thin tube, since most cage ("car") battery hydrometers are too large to fit into bike batteries. On the other hand, if your bike is a kick-start, it doesn't depend on the battery too much, and checking it is less important.
* If the headlight gets brighter as the engine revs, the battery could be discharged (or dead), though it's probably more likely that the voltage regulator is toast. $80-120 for a new one, plus half an hour of labor to install. Don't compare brightness at idle to brightness at 10,000 rpm... compare ~2,500 rpm to ~7,000 rpm.) It's hard to diagnose this problem by headlight brightness alone, but for starters, try charging the battery and repeating the test, or, if that doesn't work, replacing the battery and repeating the test. If it's still getting brighter as revs go up, try testing voltage across the battery at ~3,000 rpm... should be 13.8v or so. Less than 13.2 (or more than 14.4) and you probably have a bad stator (~$300 for a new one, ~$150 to get the old one rewound) or a bad regulator (prices as noted above.) This probably sounds pretty involved, and it probably is, if you don't know what you're doing. You may want to look for a bike that won't require as much work... taking the bike to a mechanic for a professional diagnosis will cost you $50-$100 or so, but will help you make that decision. If you have your heart set on this bike, it's probably worth it; otherwise, it probably isn't.
SUSPENSION
* Ask the owner how long it's been since the fork seals have been changed (miles and/or years.) They should probably be changed every 15-20k miles. Replacing them is not necessarily a complicated fix, but it is if you don't have the right tools, and most people don't. (Approximately $100 of parts -- fork bushings usually get done at the same time -- and 2-3 hours of labor.) Straddle the bike, grab the front brake, and push down vigorously on the forks. They should go down and come back up with some resistance. Do this a few times. Inspect the chromed fork legs. [1] They should a) be smoother than a baby's bottom with absolutely no scratches, nicks, or roughness, and b) be utterly and totally devoid of little oil droplets. (Some nicks/scratches/gouges/surface rust can be polished off, but if they can't, new fork legs can be expensive. Have a professional mechanic advise you on what the prognosis is.) If, after bouncing the forks, you see little rings of dirt, that's probably fine, but wipe them off with a rag and bounce the front suspension a couple more times. Not good if you see oil left on the fork legs after you do this.
* Check the steering head bearings and swingarm bearings as mentioned in the section on centerstand checks, below. (If the bike doesn't have a centerstand, you might be able to use a jack or work stand to raise the bike off the ground, but be very careful not to damage a bike that you don't own.)
* The suspension should move up and down almost silently if you bounce it up and down. Clunking or squeaking noises are bad. Binding is very bad. Run away.
* Suspension fluid needs to be changed every year or two, as it tends to break down and thin-out over time. Ask the owner how long it's been since the fork oil has been changed. (The suspension oil in the rear shock of most bikes isn't generally user-serviceable, but should be changed periodically by a professional suspension shop nevertheless.)
* Get someone to stabilize the front of the bike, you stand behind it. Push down on the bike's grab rail (or passenger seat), hard. The bike should spring back up, but with a little resistance. If you don't feel any resistance at all (like you're just pushing down on a spring), it's time to replace the rear shock. (Reasons: either a seal has failed inside the shock, or the oil has broken down so much that it doesn't provide useful resistance.) Around $350 from a dealership, plus 3 hours of labor to install it. If you're not sure if you'd know a blown rear shock if you felt one, don't worry about this one. But do this to all the bikes you look at (including new bikes at dealerships) and you'll know what a rear shock should feel like.
* As noted in HAS IT BEEN CRASHED?, check to make sure the fork tubes are straight (not bent) and parallel (not twisted). Sight down them and pay particular attention to the chrome tubes.
* Certain premium aftermarket suspension units (Penske, Ohlins, Fox, Race Tech) offer substantially increased suspension performance and are fully rebuildable. Expect to be asked to pay a little more for these units (as described in ACCESSORIES, PRICE, and DEALING, below.) These units also tend to be able to go longer before needing service compared to stock suspension components. Aftermarket rear shocks often have remote reservoirs (typically a cylinder "piggybacked" to the main rear shock body or attached to the frame and connected via a hose), though since many late-model high-performance bikes come from the factory with remote-reservoir shocks [2], it pays to do a little research to find out whether the bike you're looking at came with one stock, or had some money put into upgrading its suspension.
