Flywheel weight on Yz450f


10 replies to this topic
  • brolo747

Posted June 30, 2007 - 03:41 PM

#1

Can someone explain to me where they install. What weight and what are the advantages vs. disadvantages of different weight?:thumbsup: I have an '03 yz450f that i am converting for trail use also. I am unclear as to what, how, where the flywheel is and goes. :cheers:

I was assuming the flywheel is the gear behind the clutch basket :thumbsup: (like on a car). But I see yamaha, honda, and for all I know all the rest of 'em. Label the magneto as the flywheel. Please help. Thanks in advance.:busted:

  • UltraHyper

Posted June 30, 2007 - 04:19 PM

#2

You replace the whole flywheel, I just bought one on ebay this week so Im waiting for delivery can wait to see the difference it's 3oz more then stock from GYTR, and you can get different weight

  • yamirider5588

Posted June 30, 2007 - 04:23 PM

#3

Yes , the magneto and the flywheel are the same component . basically what you are doing is adding something like this ZIP-TY to the flywheel . Super simple to bolt on and the results , for me , were outstanding . It de-tuned the ' hit ' of my 04' into much more usable power . I went with a 6 oz. weight on one side and steel clutch plates on the other . I still have tons of torque , it just gets to the ground without all the wheel spin .

I went through the debate of whether or not to get one . A lot of opinions / advise was to learn throttle control . The other side of the debate ( mostly from the seasoned experts ) was that they vastly improve traction , especially in tight technical terrain . I'm glad I went with the experts opinion . :thumbsup:

  • grayracer513

Posted June 30, 2007 - 05:07 PM

#4

Actually, the part in question is the magneto (or generator) rotor. A magneto needs to have both a rotor and a stator to be a magneto. The rotor could be a small cylindrical component within a field of coils, as it is in the AC generators of older British bikes, or larger, basket ro bowl shaped rotor with the field coils inside it. In most Japanese dirtbikes, as well as others, the mag rotor is of the latter type, and doubles as and engine flywheel. An engine flywheel would not be placed behind the clutch on a motorcycle under normal circumstances, since the clutch is not mounted on the crank, and because there is a reduction gear between the engine and trans, where the clutch is. The flywheel would need to be over 3 times as heavy in order to have the same inertia effect on the engine.

Why a flywheel? Because an engine, particularly a single cylinder engine, does not run at a steady speed. It is only powered through about 80-100 degrees of revolution, and has to rely on momentum to rotate the 600+ degrees to the next power stroke. The flywheel adds momentum to help maintain engine speed at low rpm.

The two reasons you might use a heavier one are to smooth out the engine operation, and help prevent stalling at low speed for trail riding, and to give the engine a little more work to do in the lower gears to help reduce runaway wheel spin.

Flywheel weight is added by either bolting on a specially made weight, or by welding a weighted ring in place. In the case of the welded weights, the entire flywheel is exchanged for the heavier one, as welding the weight in place usually requires some truing and rebalancing of the flywheel. The welded weights are both more dependable, and more effective per ounce added, since all of the added weight is concentrated on the outer edge of the flywheel.

  • tnl

Posted June 30, 2007 - 06:57 PM

#5

Can someone explain to me where they install. What weight and what are the advantages vs. disadvantages of different weight?:thumbsup: I have an '03 yz450f that i am converting for trail use also. I am unclear as to what, how, where the flywheel is and goes. :cheers:

I was assuming the flywheel is the gear behind the clutch basket :thumbsup: (like on a car). But I see yamaha, honda, and for all I know all the rest of 'em. Label the magneto as the flywheel. Please help. Thanks in advance.:busted:


The following link will show you where the flywheel/rotor is: http://oem.thumperta...Fgenerator.aspx. It is located behind the left case cover part #2 (behind your shifter). More weight= more inertia. I just bought the 6oz from these guy's and would recommend using them: http://www.dubachracing.com/. Call them for any technical questioins if you can't get them here.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted June 30, 2007 - 08:38 PM

#6

On an '03, I'd use an 8oz. In fact, I do. The 6 wasn't enough for the snappier '03 engine.

  • tnl

Posted July 01, 2007 - 07:40 AM

#7

I actually didn't feel much of a change with the 6oz on mine? My gearing is too tall right now maybe that is why? I'm running a 15/51 which I use for dune riding.

  • grayracer513

Posted July 01, 2007 - 09:17 AM

#8

It isn't a real obvious change with an '03 450, either, but you start to notice that in certain situations where the bike would simply tear the tire loose before, it is now more prone to lift the front wheel and go. When powering out of loose corners, you'll find yourself staying with or pulling away from the same bikes that used to give you fits, and managing the throttle won't be quite so mentally demanding as it was.

  • brolo747

Posted July 01, 2007 - 11:48 AM

#9

Thanks for all the help everyone. Does anyone know of some articles I can read to do more research. I am mostly interested in finding out what would be the proper weight for my riding style. :thumbsup:

  • nam6667

Posted July 01, 2007 - 04:20 PM

#10

Can someone explain to me where they install. What weight and what are the advantages vs. disadvantages of different weight?:thumbsup: I have an '03 yz450f that i am converting for trail use also. I am unclear as to what, how, where the flywheel is and goes. :cheers:

I was assuming the flywheel is the gear behind the clutch basket :thumbsup: (like on a car). But I see yamaha, honda, and for all I know all the rest of 'em. Label the magneto as the flywheel. Please help. Thanks in advance.:busted:

My (9.21 oz) flywheel slows down the power just enough to make it fun for an old man to ride. It also eliminated the stalling when the rear brake was applied.

  • krazeplumber13

Posted June 19, 2013 - 05:12 PM

#11

How much ,via experience ,with 9.21 ounce flywheel or should I say how hard is it to slow down into corners as brake and throttle are applied or does anyone notice





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