[isaac]

Just to let everybody know: I fixed my starter clutch problem permanently by...replacing it. But the GZ250 starter clutches were a ripoff (at least $130) so I bought a used GN250 starter clutch ($70) because everybody said they're the same engine.

The GN250 starter clutch will work on a GZ250, but needs some part swapping to make it work.

The engines might be the same, but the starter clutch isn't. It's a very similar design aside from some cosmetics, but the flywheel attached to it does not work. The magnets on the GN250 flywheel interfere with the GZ250 stator, so you have to unbolt the GN250 flywheel from the starter clutch and bolt the GZ250 flywheel to it so you can use it. Be sure you use loctite on the bolts and get them torqued right by holding the flywheel in a vise or something. If they back out while you're riding, it can destroy a lot of things. When you slide it all back onto the crankshaft, be sure the beveled inner race on the copper washer around the crankshaft is facing toward the engine, not outward, or the clutch will be jammed against the flywheel and the starter will be permanently engaged.

How to remove the starter clutch:

1) Tilt the bike onto its right side so the left side engine cover is facing up. Lean it against blocks, a jackstand, something sturdy. This will let the oil drain out of that case so that you don't have a mess. All you need is a 45 degree lean or so to the right.

2) If you have to do this job, do yourself a favor and buy a 3 jaw gear puller and an electric impact wrench now. They're absolutely necessary, and this is coming from a guy who's made an 18-year amateur career out of using the wrong tools to disassemble and reassemble entire cars because the right ones were too expensive, so I'm serious. They're absolutely necessary. You do not want to risk shattering a gear or flywheel or cracking the side of the crankcase prying away in a futile attempt to get the flywheel off without the right tools. And when I say futile I mean it. That starter clutch and flywheel will not come off without these tools.

Why do I need an impact? For the crankshaft nut, you need it so you don't have to hold the crankshaft with a breaker bar on the other end, which is not an easy one man job and takes much longer. With an impact, you just pull the trigger and the nut is off in seconds. No holding the crank necessary. You're also using an impact here because the vibration from it makes it so far less force is required (though still tremendous) to free the parts than a traditional breaker bar.

3) Even with the right tools, the starter clutch/flywheel assembly will more or less explode off. There is a mind-boggling degree of force necessary to free that assembly from its coked-up gorilla grip on the crankshaft. It's insane. Be really damn careful.

4) Once you use the impact to get the nut off the end of the crankshaft, you'll need to use a 3-jaw puller to remove the flywheel/starter cluch. If you buy the same 3-jaw puller I did (which is the same as pretty much all of them), you'll need to grind away at the inside of the arms because there's interference where the arms wrap around the flywheel. You need the ends of the arms to have a good grip on the flywheel. And you will want to use it on the nice thick flywheel, not the brittle, thin starter gear, which would snap in half under the force you exert here. Lube up the tip of the crankshaft and the gear puller shaft so they don't wear away at the metal under the tremendous force you're putting on them. Stuff rags into the holes in the side of the crankcase. You do not want small parts flying into there when the starter clutch explodes off the side of the engine, which it will.

5) Once everything's tight and ready to go, that's when you bring in the impact. When you use the impact wrench, it will require far more force than you ever believed necessary. This will cause, as I've said many times, an explosion of parts. Once it lets free from the crankshaft, it does it with a big bang. To minimize parts flying everywhere, get some towels to cushion the blow. Put one under the bike, stuff some in the frame rail holes so nothing can go in there. Just make it so if something goes flying, it won't go far. The parts that will try to disappear are 3 starter clutch rollers, 3 pins, and 3 springs.

6) Spray PBlaster into where the assembly is pressed onto the crankshaft. This will help reduce the force necessary to take it off. Then start using the impact on it. This will take a while. Have goggles on or even a damn helmet for this. Hit it in a few quick bursts at a time, over and over. It'll let go with a bang. Then collect your parts.

When you've found them all, then you can do all that other stuff I mentioned. Just be sure to keep everything in order. Good luck.

PS If after you removed all this stuff it turns out your crankshaft sheared its flywheel alignment pin completely off like mine did, and you need to weld metal onto the crankshaft and grind and shape it to replace the old pin, I can give you tips on that too.