TEORIA

[Soso]

stiu ca toti stati bine la capitolul practic, insa eu catu sa aflu partea teoretica.orice link-uri, texte sau altceva, privind tehnica mersului la offroad, sfaturi, studii, tips&tricks cred ca vor fi apreciate.

 

1.PORNIREA LA PEDALA

With the four-stroke revolution bumping the rev limiter, more and more two-stroke fiends are entering the world of cams and valves and pumper carbs. The biggest dilemma these converts will face will be lighting the fire within the beast. So, weâve enlisted the top revolutionaries in the sport to teach the masses how they do it. With dead-engine starts the norm in GNCC competition, we went to the Ironman Cross Country and picked the brains of YZF pilot Randy Hawkins, DRZ guru Mike Kiedrowski, 650R hero Scott Summers and sometime 520EXC pilot Shane Watts. Theyâll cover cold-starts, dead-engine-starts and what to do after a fall or stall.

SUZUKI DRZ400

Start the bike like Mike

Cold starting: Iâll pull the choke knob and compression release and kick it through until the compression lever snaps back out. That tells me itâs at Top Dead Center (TDC). Then simply kick. Or you can kick through until you feel resistance, which is the compression stroke, then pull the decompression lever slightly and ease the kickstarter to TDC. Let it warm up before taking the choke off.

Starting a flooded bike: If I fall, Iâll flip the Terrycable Hotstart lever open, pull the compression release, open the throttle and kick it through five times. That way, Iâm getting fresh air and fresh gas in there to replace that bad mixture. Then Iâll bump the kicker to find TDC then kick hard. Be sure to turn the hotstart back off before getting going.

 

Race start: At the first of the season, Iâd warm the bike up on the line then hit the kill button. Then Iâd find TDC with the auto-decompressor, return the kicker to the very top, and get set to stomp it with the clutch in and tranny in first. But Kenny, our engine guy, showed me that if you simply pull in the decompression lever with the engine running, itâll always stop at TDC. So, simply hit the lever with it in gear and the clutch in, and itâll be ready to start. l

YAMAHA YZ426F

Quick tricks from the Javeline

Cold starting: Yamaha says to twist the throttle twice to prime the carb, but I pull in the decompression lever, kick it through four or five times, find TDC, let the decompressor go, then return the kicker to the very topâthis is very importantâbefore kicking hard with no throttle. Iâll use the choke if I can reach it, but thatâs not always possible with big off-road gastanks.

Starting a flooded bike: The big key with all four-strokes is not to panic. If you pick the bike up and start flailing away, youâre going to cause problems. Iâll take an extra second to find neutral, kick it two or three times with the hotstart and decompressor engaged, release both, find TDC and kick. It seems a little bit longer, but it almost always starts quicker than panicking. Again, no throttle!

Race start: I start in first, but youâre probably talking to the wrong guyâI donât get good starts. Four-strokes donât light up instantly like two-strokes; it takes a while to get going. Itâs hard to hear your engine on the line, too. In the heat of battle, itâs easy to twist the throttle too soon or by instinct, so Iâll have two fingers on the front brake. This costs a couple of bikelengths, but the alternative is worse.

So, Iâll warm it on the line and, with a small amount of throttle, Iâll hit the kill button. Then Iâll give it a couple of primer kicks with the decompressor before finding TDC and returning the kickstarter to the top of its stroke. Iâll poise over the lever with the clutch in and the tranny in first and two fingers pulling the front brake, then I focus on the green flag. L

HONDA XR650R

Hot tips from the nine-time champ

Cold starting: The only difference between cold starting and my regular starting procedure is that when the engine hasnât been running Iâll use the choke. XRs have two different choke positionsâall the way up is full choke, and one notch down is half choke. I use full choke when the bike is cold; the bike will let you know when it wants half chokeâit will eventually start running roughly in the full choke position. As the bike is warming, I try to keep the choke in the position that allows the bike to run smoothly, which means in just a few moments you go from full choke, to half choke, to no choke.

As for a typical XR (and most other four strokes), here is what Iâve found works. Push the kickstarter down slowly with your foot until you feel a hard spot. The kickstarter will stop (you may feel a bunch of resistance immediately or you may have to run the kickstarter through its range of motion once or twice before you feel that resistance that stops your foot). Next, pull the compression release lever in and push the kickstarter just past the hard spotâmoving the kickstarter about an inch or twoâthen let the kickstarter come back up to itâs resting position. Itâs now ready to be kickstarted. You donât have to snap at the kickstart lever like you would a two stroke. Think of it as using your foot to shove the lever downward; it doesnât have to be two-stroke quick but you want to put your weight into it, to get that mass of heavy engine partsâpiston, crank, flywheelâin motion. To further decrease the amount of effort necessary to get these parts moving quickly, put the bike in neutral. When you give the bike this first real kick it should start.

Starting a flooded bike: After crashing, I pick up my bike, hold the throttle wide open, compression release in, kill button pushed in, then I kick the bike through four or five times. Next, I go through my normal starting procedure (no choke, the bike is warm). If the bike doesnât start on the first kick, I repeat the flooded procedure.

Racing start: At the beginning of a race, I use the normal starting procedure. Before the flag drops, I have the kickstarter in the ready-to-be-started position. I put the bike in gear and with the clutch in. I roll the bike back and forth just a little until the rear wheel moves freely, this is an indication that the clutch is completely engaged, so the amount of drag on the engine is minimal. If the bike wonât roll freely with the clutch in, it should be adjusted accordingly. You canât grab a handful of throttle as you start a four-strokeâif you do it will stall. For this reason, Iâm not known for great starts because I have to give up a bike length or two waiting for the bike to be running before I start twisting the throttle and dumping the clutch. I start in first gear.

Common mistakes: Most four strokes Iâve ridden, when jetted properly, donât want any throttle when being started. Itâs habit for most two-stroke riders to twist the throttle as they kick. If Iâm helping someone start their bike, Iâll first use no throttle. If it doesnât start Iâll try using just a fraction of throttle. If it comes to life, that generally means the pilot jet or air screw is too lean or the idle is too low and the engine isnât getting enough fuel. If the bike had not started I would then go through my flooded procedure to see if it might be getting too much gas, meaning the jetting is too rich.

Four strokes donât foul spark plugs like two strokes, so donât jump to the conclusion that this is the problem if the bike wonât start. Spark plugs can get a drop of water on the electrode and stop working, so, if the bike has been around a lot of moisture, you might need to pull the plug out and dry it off. When I know my bike is jetted properly and my starting method is correct, the first thing I do if the bike wonât start immediately is drain the carburetor. Itâs easy to get some water in fuel, and fuel does go bad when sitting in a carburetor for a while.

KTM 520

Suppose the battery is deadâŚ

Are you nuts? Charge the battery! Watts used the e-button every time he raced the 520, 400 and 250 RFS KTMs! Actually, the electric starter is a little slow for Pro Row starts, but it gives great confidence for charging turns. If you do lock it up, simply pull in the clutch, hit the button, and dump the clutch! Youâll lose only a fraction of a second. For you SX owners:

Cold starting: Gas on, choke on, twist the throttle once, no throttle kick. Repeat until it starts.

Starting after a fall: KTM doesnât have a hotstart system, but you could put on a Terrycable KLX Hotstart kit, which requires drilling your manifold.

Failing that: engage decompressor, open throttle, kick through four or five times, release decompressor, close throttle, kick. With a hotstart: flip hotstart lever, kick, close hotstart.

Race start: Warm engine, put it in gear, release clutch to kill motor. Rock it to make sure clutch isnât dragging, find TDC, return kicker to top of stroke, kick when the flag twitches.

 

 

2.TEHNICI PT 4T CAPACITATI MICI

 

SMALL THUMPER RIDING TIPS--JAN â99

Chris Smith has made his mark riding small-bore bikes in big events. A member of the winning â91 Junior Vase team in Czechoslovakia, Smith has five ISDE Gold medals and one silver out of seven tries. He has earned those medals aboard small-bore two-strokesâa class Europeans ownâbut now heâs facing a new challenge, the 250cc four-stroke class. This wonât be totally alien ground for him, because heâs used to building lots of momentum with tiny pistons, and he cut his moto-teeth on four-strokes.Smith turned some heads and shocked many two-strokers by making podiums on an almost-stock XR250R in Qualifiers and National Enduros this summer. What he has learned about bike set-up is available to the masses through Works Enduro Rider, and Chris is also passing on his technique through four or five riding schools a year. While Chris was out for the XR shootout, we got him to demonstrate some of his tactics for the DB lens.GO-FAST STRATEGIESSmithâs go-fast plan begins before you ever sling a leg over a bike. In his school, he talks about practice and preparation. You should work on breaking bad habits in practice, not just burning gas and wearing out your bike. Record all changes you make to the bike, so that you can return to them more quickly when you face similar conditions at an event. He also covers pre-race hydration, being positive and focusing on the task at hand. That task is to go faster than the next guy and to have more fun, too.Like Professor Bailey and Holeshot Hansen, Chris starts with the basics of styleâbody positioning. Your basic moto-style is a study in aggression with elbows up, weight forward on the bike, fingers on the clutch and front brake, and the balls of your feet on the pegs. Smith stands up as much as possible and looks far ahead on the trail. He likens position on the bike to riding rodeoâclamp on just behind the front shoulders of the bull, because all of the action happens out back. Shift your upper body to make corrections, but once you get too far back, youâre in for a fall. Itâs the same with a dirt bikeâstay forward to move forward. And maintaining forward momentum is what riding any small-bore is all about. Especially 250cc thumpers.THINK MOMENTUMThereâs more to momentum than bumping up against the rev limiter for hours on end. Smith concentrates on finding traction and creating it when grip is scarce. He loads his front end by dragging the front brake through turns, and Chris picks lines that miss the braking bumps. Most riders will enter a turn on the inside then drift out at the exit. Smith does the opposite. He sets up wide, missing all of the braking bumps and carrying more speed, then cuts inside, missing acceleration bumps. Done right, you can even use the last braking bump as a berm for your pivot.Where most people brake entering a turn, Smith brakes early and in a straight line, then he accelerates all the way around the turn. He concentrates on never locking up either brake and on rolling on the throttle. And Smith never pulls in the clutch for corners, because then you lose that magic four-stroke compression braking. Besides looking for maximum cornering speed, Chris is searching for maximum traction at all times. This means feeling which end is about to slip and shifting his upper body to weight that end.FLOATING THE OBSTACLESEvery bump you hit tries to soak up your momentum, so Chris looks for lines that miss them completely or minimize their affect on the bike. Smith unloads his weight off of the pegs to preload over bumps and goes so far as to not pull back on the bars for logs. He bounces the front tire into the log (a trials move) to transfer weight back and give the rear tire more traction over the log. Chris also looks for the lowest part or a knot to place the wheel against, so it wonât slip. Then he simply coasts over the downed tree.Roots and rocks are the same dealâbrake and accelerate before and coast over the worst of it. Accelerate where there is traction and float where there is none. This avoids wheelspin, momentumâs worst enemy. Chris goes over rocks instead of between them, using them as ramps. That is, when he canât avoid them completely by riding the edges of the trail. Smith attacks roots near the base of the tree, because thereâs more bark - and traction - to be found there. He also bounces the front end over, as with logs.Smith deals with ruts by braking beforehand and accelerating through them. He teaches his students to stand up, ride on the balls of their feet, relax and use the upper body to stay straight. Looking well ahead is also very important, because looking immediately past your front fender leads to over-corrections and loss of momentum. Watch Chris ride, and youâll see him working with the bike and leading it through every situation. Heâs being pro-active and even thinking two turns ahead, of how heâs going to set up for the next obstacle.PODIUMS NO OBSTACLEVictory podiums are tall and slippery, but you can slither up them on a small-bore four-stroke. Chris Smith has, and he can show you how to do it, too. For more information on his riding schools, contact Chris at Works Enduro Rider, 1 Jenny Jump Ave., Great Meadows, NJ 07838; (908)737-6385.

 

ASTEPTAM PROVINCIA

[digitallysane]

Hei Soso, faci o scoala on-line?

 

Sper sa ajung in postura de a experimenta chestiile scrise aici.

 

Multumiri.

 

Dragos

[Dobrescu]

Soso, materialul asta trebuie tradus si pus la articole!!

[Pit]

ce soso nu sti sa iti pornesti mobra la kick si ai cautat pe net ?

[Soso]

pit, nerecunoscatorule. esti invidios ca nu te regasesti in lista de motoare?

pune mana si scrie daca ai ceva interesant pt noi.

@degetarusanatos......nu sunt in postura sa fac scoala, sunt elev

sper sa mai invat si eu de unde pot

[DragosKTM]

Soso, da' ti s-a stricat botonul la WRF ?!? Nu-i mai simplu ( si mai rapid) sa-l repari, dacat sa citesti toata asta ?!?

[Soso]

dragos, nu numai ca s-a stricat, dar a disparut cu totul.yamaha a introdus pornirea la buton abia cu wr450f model 2003.eu am wr400f, model 98