Issue Date: Archives, Posted On: 5/30/2001 5:26:47 PM


4-STROKE STARTING TIPS

4-STROKE STARTING TIPS


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, we?ve 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. They?ll cover cold-starts, dead-engine-starts and what to do after a fall or stall.

SUZUKI DRZ400
Start the bike like Mike

Cold starting: I?ll pull the choke knob and compression release and kick it through until the compression lever snaps back out. That tells me it?s 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, I?ll flip the Terrycable Hotstart lever open, pull the compression release, open the throttle and kick it through five times. That way, I?m getting fresh air and fresh gas in there to replace that bad mixture. Then I?ll 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, I?d warm the bike up on the line then hit the kill button. Then I?d 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, it?ll always stop at TDC. So, simply hit the lever with it in gear and the clutch in, and it?ll 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 top?this is very important?before kicking hard with no throttle. I?ll use the choke if I can reach it, but that?s 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, you?re going to cause problems. I?ll 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 you?re probably talking to the wrong guy?I don?t get good starts. Four-strokes don?t light up instantly like two-strokes; it takes a while to get going. It?s hard to hear your engine on the line, too. In the heat of battle, it?s easy to twist the throttle too soon or by instinct, so I?ll have two fingers on the front brake. This costs a couple of bikelengths, but the alternative is worse.
So, I?ll warm it on the line and, with a small amount of throttle, I?ll hit the kill button. Then I?ll give it a couple of primer kicks with the decompressor before finding TDC and returning the kickstarter to the top of its stroke. I?ll 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 hasn?t been running I?ll use the choke. XRs have two different choke positions?all 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 choke?it 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 I?ve 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 spot?moving the kickstarter about an inch or two?then let the kickstarter come back up to it?s resting position. It?s now ready to be kickstarted. You don?t 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 doesn?t have to be two-stroke quick but you want to put your weight into it, to get that mass of heavy engine parts?piston, crank, flywheel?in 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 doesn?t 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 won?t roll freely with the clutch in, it should be adjusted accordingly. You can?t grab a handful of throttle as you start a four-stroke?if you do it will stall. For this reason, I?m 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 I?ve ridden, when jetted properly, don?t want any throttle when being started. It?s habit for most two-stroke riders to twist the throttle as they kick. If I?m helping someone start their bike, I?ll first use no throttle. If it doesn?t start I?ll 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 isn?t 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 don?t foul spark plugs like two strokes, so don?t jump to the conclusion that this is the problem if the bike won?t 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 won?t start immediately is drain the carburetor. It?s 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 dead?

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! You?ll 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 doesn?t 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 isn?t dragging, find TDC, return kicker to top of stroke, kick when the flag twitches.

 

 

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WARNING: Much of the action depict­ed in this magazine is potentially dan­gerous. Virtually all of the riders seen in our photos are experienced ex­perts or professionals. Do not at­tempt to duplicate any stunts that are be­yond your own capabilities. Always wear the appropriate safety gear.

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