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twenty34

Q: Pulling a Flywheel

8 posts in this topic

So it looks pretty straight-forward to pull a flywheel using a puller tool, but how does the flywheel go back on if force/pressure is required? I want to try a heavier flywheel and just wanted to find out if it's just as simple as pulling one off and putting a new one on?:thumbsup:

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It should be as simple as putting the new one in place and tightening the nut to the proper torque. The puller is required to get it off only.

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blue9red9 is correct...very straight forward just lay the bike on the side and you don't have to worry about draining the oil either. I assume the bike is an '06 or newer. It took me around 15 minutes to change mine out.

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The flywheel is on a tapered shaft. The torque of the nut "wedges" the flywheel center in place on the shaft to the extent that if properly set, it would stay in place for quite a while with no nut at all (but don't try that at home).

The puller is required to "unstick" the flywheel from the shaft. Quite often, you will find that the flywheel will refuse to bidge after an uncomfortable amount of torque has been applied. In those cases, strike the top of the puller pressure screw sharply in line with the crank. The shock will usually free it. Once pulled free of the taper, it no longer needs the puller, unlike pulling or pressing a bearing off or onto a straight shaft.

Installing it is a simple matter of keying the slot to the woodruff key, pushing it into place, and torquing it down. I should mention that there is some risk of catching the woodruff key with the flywheel as youj push it on and sliding or rolling it up out of the slot in the crank, which would prevent the tapers from setting properly, and could cause the flywheel to run off center and damage the stator if the engine were able to start. That would be about the only thing you could do wrong.

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The flywheel is on a tapered shaft. The torque of the nut "wedges" the flywheel center in place on the shaft to the extent that if properly set, it would stay in place for quite a while with no nut at all (but don't try that at home).

The puller is required to "unstick" the flywheel from the shaft. Quite often, you will find that the flywheel will refuse to bidge after an uncomfortable amount of torque has been applied. In those cases, strike the top of the puller pressure screw sharply in line with the crank. The shock will usually free it. Once pulled free of the taper, it no longer needs the puller, unlike pulling or pressing a bearing off or onto a straight shaft.

Installing it is a simple matter of keying the slot to the woodruff key, pushing it into place, and torquing it down. I should mention that there is some risk of catching the woodruff key with the flywheel as youj push it on and sliding or rolling it up out of the slot in the crank, which would prevent the tapers from setting properly, and could cause the flywheel to run off center and damage the stator if the engine were able to start. That would be about the only thing you could do wrong.

So the problem I'd encountered this weekend when trying to replace it was the darn nut that holds the flywheel on is stuborn (the one attatching it to the crankshaft).

I can't get that sucker to loosen. I had the bike in gear, held the rear break on and I got nowhere. I took the advice about laying the bike over so I wouldn't have to drain the oil, but I think I need to get this bike upright to get any leverage. I was pulling the racket hard too! :crazy:

Maybe an impact wrench?

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So the problem I'd encountered this weekend when trying to replace it was the darn nut that holds the flywheel on is stuborn (the one attatching it to the crankshaft).

I can't get that sucker to loosen. I had the bike in gear, held the rear break on and I got nowhere. I took the advice about laying the bike over so I wouldn't have to drain the oil, but I think I need to get this bike upright to get any leverage. I was pulling the racket hard too! :crazy:

Maybe an impact wrench?

Impact wrench, or a lock-up tool from Steahly Offroad. Its a plastic plug that goes into the spark plug hole, and the piston comes up against it, keeping the motor from turning over. Then you can put a lot of leverage on the nut without trying to lock the rear wheel up with the brake.

Or you can go low-tech and do the same thing by lowering a length of rope into the spark plug hole. I did this on my YZ250 when I put a FWW on it and it worked great.

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Well, about 30 seconds after asking how to get the nut off, I went into the garage and put to use that nifty Snap-On impact wrench that I recieved after buying my bike. I haven't used it much, but I just remembered that I had it.

Well the nut was deffinately on there, but the impact wrench took care of it. Man, that was stuborn, even with he wrench, but I'm smiling now. :crazy:

Glad I put some thought into getting the impact wrench over the torque wrench. Now I need a torque wrench, however.:D

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