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Polar_Bus

Machining the YZF450 flywheel

6 posts in this topic

I have an '07 450, and after piloting both an '06 and an 08 I seem to think my 07 has somewhat of a more relaxed midrange power delivery. I was wondering... (and this might go nowhere) about machining some weight off the flywheel to free up some rotating mass... anyone ever tried this? Any thoughts? Thanks!

PS... NO I don't wan't to add a pipe !!!!!!!!!!!

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I've never done it, but I know guys that have. It makes the bike rev faster, hit harder, but it also doesn't chug as well, and it's easier to stall.

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The flywheel is already smaller than your gas cap. It also has a lug on the outside that A) can't be removed because it triggers the ignition, and :ride: requires the slot you will see machined in the back side to restore balance. There is minimal material there as it stands, and IMO, removing almost anything from it would introduce the risk of having it blow apart at high RPM, which could be personally disastrous.

In any case, there isn't enough there to remove that it would have the desired effect.

If you want more mid-range, drop an '06 exhaust cam in it and start there. The cams are most of the difference between the two engines, and interestingly, a heavier flywheel may actually improve your low-mid output.

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The flywheel is already smaller than your gas cap. It also has a lug on the outside that A) can't be removed because it triggers the ignition, and :ride: requires the slot you will see machined in the back side to restore balance. There is minimal material there as it stands, and IMO, removing almost anything from it would introduce the risk of having it blow apart at high RPM, which could be personally disastrous.

In any case, there isn't enough there to remove that it would have the desired effect.

If you want more mid-range, drop an '06 exhaust cam in it and start there. The cams are most of the difference between the two engines, and interestingly, a heavier flywheel may actually improve your low-mid output.

Thanks,

I didn't know Yam mellowed out the exhaust cam in '07, I actually thought they (Yamaha) maybe put a heavier flywheel in my '07, I will definatley look into that.....

I was initially very happy with the relaxed power of my '07, as it made for an easier learning curve getting used to the bike in generall, but now that I am more comfortable on the chassis, I would like some more snap in the middle.

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They didn't mellow it out, they narrowed the lobe centering for more top end, and gained around 1 HP at peak by doing so. The penalty for that is a loss in the low end, though. You may also find that a Vortex ignition, or the box from an '06 could make a difference, as well.

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