22,449
edits
Difference between revisions of "Used Motorcycle Evaluation"
→CENTERSTAND CHECKS
(→WHEELS) |
|||
| Line 232: | Line 232: | ||
** Dirt bikes and some older street bikes have kick-starters that enable you to spin the engine directly. So even if you don't have a compression tester, you can at least test to see if you can feel some compression. If you spin the engine with the kick-starter and feel it get substantially harder to spin at certain points (almost like there there's a "tight spot") -- that's good: what you're feeling is compression. If you spin the engine with the kick-start lever and it doesn't really feel like there's a tight spot, the engine is probably suffering from a serious lack of compression. Run away, or, if you have your heart set on it, have the bike checked out by a shop! | ** Dirt bikes and some older street bikes have kick-starters that enable you to spin the engine directly. So even if you don't have a compression tester, you can at least test to see if you can feel some compression. If you spin the engine with the kick-starter and feel it get substantially harder to spin at certain points (almost like there there's a "tight spot") -- that's good: what you're feeling is compression. If you spin the engine with the kick-start lever and it doesn't really feel like there's a tight spot, the engine is probably suffering from a serious lack of compression. Run away, or, if you have your heart set on it, have the bike checked out by a shop! | ||
== | ==Centerstand Checks== | ||
* If the bike has a centerstand, you can test some other stuff. Put the bike up on the centerstand, have someone sit (or push down hard) on the passenger seat so the front wheel lifts in the air, then grab the sides of the front axle and try to move the front wheel forward and back (not twisting.) It shouldn't be able to move in this direction. The front wheel should rotate from full-lock left to full-lock right without binding (improper cable routing?) or feeling notchy (worn-out steering-head bearings ... see below.) | * If the bike has a [[centerstand]], you can test some other stuff. Put the bike up on the centerstand, have someone sit (or push down hard) on the passenger seat so the front wheel lifts in the air, then grab the sides of the front axle and try to move the front wheel forward and back (not twisting.) It shouldn't be able to move in this direction. The front wheel should rotate from full-lock left to full-lock right without binding (improper cable routing?) or feeling notchy (worn-out steering-head bearings ... see below.) | ||
* Bad steering head bearings will feel faintly notchy, typically when the handlebars are centered. Potholes and hard landings (from jumps or wheelies) can cause little dents in the steering-head bearing races. These little dents will make the bearing feel notchy as you (slowly) rotate the bars past the notched point. With the front wheel in the air, move the bars back and forth slowly, feeling for notches. (Make sure that cables and control wires aren't causing any irregularities that you may feel.) If the steering head bearings are notchy, they need to be replaced -- figure on $60-80 of parts and 2 hours of labor. | * Bad steering head bearings will feel faintly notchy, typically when the handlebars are centered. Potholes and hard landings (from jumps or wheelies) can cause little dents in the steering-head bearing races. These little dents will make the bearing feel notchy as you (slowly) rotate the bars past the notched point. With the front wheel in the air, move the bars back and forth slowly, feeling for notches. (Make sure that cables and control wires aren't causing any irregularities that you may feel.) If the steering head bearings are notchy, they need to be replaced -- figure on $60-80 of parts and 2 hours of labor. | ||
* Spin the front wheel and apply the brakes ever so gently. There shouldn't be a pulsating feeling from the pads. A pulsating feeling at the lever means new brake rotor(s); a pulsating sound (by itself) is probably nothing, but it could be an indication that the rotors are warped, and you should make an effort to test them at speed. Checking the rotors by spinning the wheel is pretty hard to test reliably, but do your best. Spin the wheel hard and apply the brakes gently so they slow down rather than just *stop*. As noted in the section on brakes, brake rotors are around $150-250 each.) | * Spin the front wheel and apply the brakes ever so gently. There shouldn't be a pulsating feeling from the pads. A pulsating feeling at the lever means new brake rotor(s); a pulsating sound (by itself) is probably nothing, but it could be an indication that the rotors are warped, and you should make an effort to test them at speed. Checking the rotors by spinning the wheel is pretty hard to test reliably, but do your best. Spin the wheel hard and apply the brakes gently so they slow down rather than just *stop*. As noted in the section on brakes, brake rotors are around $150-250 each.) | ||
* Next... put the front wheel back on the ground and grab the rear axle. Try to move the axle side to side. (You're checking for wear at the swingarm's pivot.) If things just feel loose back there, figure on $150 of parts (bearings, seals, etc.) and ~3-4 hours of labor. You shouldn't be able to move the swingarm side-to-side independent of the whole chassis. If you can, the swingarm bearings are badly worn. | * Next... put the front wheel back on the ground and grab the rear axle. Try to move the axle side to side. (You're checking for wear at the swingarm's pivot.) If things just feel loose back there, figure on $150 of parts (bearings, seals, etc.) and ~3-4 hours of labor. You shouldn't be able to move the swingarm side-to-side independent of the whole chassis. If you can, the swingarm bearings are badly worn. | ||
* Check axle alignment. Hard to do 100% properly without a pair of 8' straight-edges, but look at the axle alignment marks on the sides of the swingarm and/or sight down the rear wheel to see if it's in line with the front one. Not something that's easy to detect, and it'd probably suffice to just look at the axle adjustment marks on each side (look for hash marks on the swingarm, right near the axle.) There's a way to check axle alignment with 10-15' of string, but it's a little hard to explain. Fortunately, Motorcycle Online has published a pretty good article on how to do it. | * Check axle alignment. Hard to do 100% properly without a pair of 8' straight-edges, but look at the axle alignment marks on the sides of the swingarm and/or sight down the rear wheel to see if it's in line with the front one. Not something that's easy to detect, and it'd probably suffice to just look at the axle adjustment marks on each side (look for hash marks on the swingarm, right near the axle.) There's a way to check axle alignment with 10-15' of string, but it's a little hard to explain. Fortunately, Motorcycle Online has published a pretty good article on how to do it. | ||
==SERVICE== | ==SERVICE== | ||