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How To: Un-Trash Your Z400 Stator
042505 ::.

How To: Un-Trash the Suzuki Z400 Stator
...from a flywheel bolt malfunction.

Contributing Editors: NJC & Was123
Photos: NJC

As time wear's on, the Suzuki LTZ400 ATV's (early models in particular) are starting to show problems with the flywheel bolts coming loose and backing out of the magneto. This can and will result in the bolts making contact with the stator - causing it to get chewed up while possibly shearing off the flywheel bolts. This can be fixed however with the right tools in hand.

If you are sure there is a problem and need to replace parts, the first step is draining all the oil from the engine case. If you think there are no problems yet and just want to check for preventative maintenance, then tilt the quad to one side so all the oil will not run out once you remove the cover. Once the oil is drained or tilted begin by removing the starter cover on left side of the engine. Follow with removing the torque limiter gears inside the starter housing as shown:

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There is a small steel sleeve or bushing that slides on the shaft on the inside of the gear cluster. Once you remove the gear cluster, make sure you also remove the sleeve if it remains inside the starter housing. If the sleeve remains in the gear cluster then you're fine. It will look like this.

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Once finished, start removing the side cover bolts - keep them organized in a parts can or ziplock bag. There are two different lengths of side cover bolts so keep a mental note on which bolts were longer than the others and where they belong. It may be tough at first to remove the side cover once you have removed all the bolts but lightly tap on the cover with a rubber mallet and remove it slowly. The outer part of the starter housing is also part of the side cover and has an o-ring. It will fit snug, so you may have to pull hard on the top of the cover to remove it.

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If you're careful, you may be able to save your side cover gasket, but chances are it will probably rip. No worries though, they only cost about $5 from the Suzuki dealer.

After you remove the side cover, you will notice the stator is attached to the inside of the cover by three allen head bolts. Two bolts hold a small component of the stator to the side of the cover and one more holds the wires in place. Remove all the bolts and then the stator off the side cover.

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Chances are you're doing this project because of an engine failure. If so, it might look something like this inside your magneto.

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Now, in order to proceed with replacing sheared off flywheel bolts, you MUST have a specific puller in order to pull the flywheel off the crankshaft. It is a 38mm X 1.5 puller and is shown below.

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You need to start by removing the retaining nut (which is left hand threaded) on the outside of the magneto. Use a 27mm wrench to hold the flywheel steady as you remove the retaining nut.

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Once the retaining nut is removed, then install the puller onto the threads on the flywheel. This is a bit tricky but you need to use a large pair of channel locks or a large crescent wrench and hold the puller steady as you turn the bolt in the middle of the puller, inward. The bolt in the center of the puller needs to turn inward towards the crank to remove the flywheel. Once the flywheel breaks loose from the crankshaft be cautious, it will come off in a fast motion.

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If you hold up the flywheel you will notice that there is a ring on the back that holds the starter clutches in place. This ring is held on by the six bolts that have come loose.

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The sheared off flywheel bolts need to be removed. In my case they were loose enough to spin out by hand but may need to be drilled out if they are too tight.

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You can do this either before or after you remove the starter gear and flywheel ring. Next, you need to remove the keyway (which you can see in previous picture) in the crankshaft in order to slide the starter gear and flywheel ring off the crank. I used a small punch and a hammer and lightly tapped it out. Then remove the small starter gear at the top - it will simply slide off. Take caution not to loose the washer that is behind this gear.

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Slide the gear and ring off the crankshaft and remove the starter clutches from the center of the ring. Inspect the parts for any damage or abnormal wear. It should look something like this after you move it.

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Make sure the retaining spring that holds all the little bearings together is in good condition.

Your next step is to clean the out the inside of the magneto thoroughly to remove any metal shavings or pieces of the stator. Then use alcohol or contact cleaner to clean out the threads in the flywheel retaining ring where the new allen head bolts are going to be installed. Make sure after you clean them that they are dried thoroughly as well. Once you have done this, then re-install the starter clutches in the flywheel with the flange facing outward to the rotor (refer to pic above) and attach the retaining ring to the back of the flywheel using new, high grade allen head bolts coated in high strength Loctite. All six of bolts must be replaced, regardless if they appear to be acceptable!

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Don't forget to use Loctite on these bolts or you will more than likely be doing this whole project again! After you have installed the new bolts with loctite, you MUST torque them to 12 NM while using the 27mm wrench to hold the flywheel steady.

After the new flywheel bolts have been installed and torqued correctly you can re-install the magneto back onto the crankshaft. First, you must re-install the crankshaft keyway. Set it in the groove in the crank and lightly tap it into place making sure it is evenly tapped on both ends of the keyway. Now you can install the magneto back onto the crank. Line up the slot in the center of the magneto and push it onto the crank as far as possible. You must use the retaining nut to re-install the magneto all the way.

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The retaining nut on the outside of the crankshaft must be torqued to spec. - 101.5 ft. lbs.. Hold the magneto with the 27mm wrench to torque the nut, then re-install the small starter gear at the top.

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Next, install the new stator (if yours is chewed up) on the magneto cover. You must clean out the magneto cover to remove any metal shavings or particles of the old stator before you install it. Make sure not to leave out the small metal clip that holds the wires out of the way of the stator. Once you have the new stator installed onto the cover, you can re-install the cover using a new cover gasket if you couldn't salvage your old one. Remember to put the cover bolts in the right places since some of them are different lengths than others.

Put the starter torque limiter (gear cluster) back into the starter housing and remember, DO NOT misplace the little sleeve that goes with the gear cluster. Here's the pics again just incase you forgot.

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After you have installed the gear cluster in the housing, you can put the small starter cover back on and double check the side cover bolts to make sure all are tight. Last step, top the motor off with fresh oil if you drained it. If you've done this project only to check your flywheel bolts, chances are didn't drain your oil. If you're doing this to replace parts then replace the oil and filter. A service manual is good to have for this project but you may get by without one with these directions. Good luck!

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