Help me understand

5 replies to this topic
  • bkklett

Posted October 23, 2007 - 03:36 AM


I have read many pages on here and many people talk about flywheel weights. Some are using 4oz others 7oz and 9oz. What is the benifit of adding a weight that weighs more. I have a 03 450. :crazy: What weight do you add? I assume that depending on what type of riding you do is linked to what size flywheel weight you would use. I only use my yz for hillclimbing. Any help in understanding would be great.

  • Racer808

Posted October 23, 2007 - 03:47 AM


The flywheel weight adds inertia to the existing flywheel so it continues spinning more so then stock. It will help prevent stalls. I put a heavier (10oz) on my sons kx when he was learning to ride, it helped mellow out the hit and helped him not stall it out in corners. But after a few months I thought it was hindering him so we took it back off. Woods riders seem to love them though. I am not sure if they would be a benefit for hill climbs though

  • grayracer513

Posted October 23, 2007 - 06:52 AM


As said, adding weight to a flywheel adds rotating inertia to the entire engine assembly. Inertia resists changes in speed, either acceleration or deceleration, and adding more will do two things. First, it will help keep the engine running at low speeds without stalling. It will also help increase low speed acceleration in marginal traction by resisting the tendency of the engine to accelerate too quickly.

I use the 8 oz Dr.D flywheel on my '03, and IMO, this or the heavier of the two GYT-R flywheels (GYT-5TA97-50-50) is the flywheel the '03-'04 should have come with in the first place. It has no effedt on top end or higher gear performance, and actually improves acceleration in lower gears very noticeably by resisting breakaway wheel spin.

Whenever you are comparing flywheel weights, keep in mind that they are of two basic types, and that these two types cannot be directly compared on an ounce-per-ounce basis. The bolt-on weights require drilling and tapping, fasteners that can potentially loosen, and can be installed improperly (although it's not that hard to do it right), and can cause a balancing problem. Welded on weights are permanently added to the flywheel, can't come off, and are balanced after installation. Also, because all of the weight of a weld-on is located at the edge of the flywheel, an 8 oz welded weight can add more inertia mass than many of the 10 oz or heavier bolt-ons.

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  • bkklett

Posted October 23, 2007 - 09:18 AM


Thanks for the great info- Just a question though? What would be good for my application. I think this would help me in my holeshots from the starting line when I hill climb. I tend to either not hit it hard enough or hit it to hard and wheelie on the start ( I run stock class, stock lenghth swingarm). I can run with the pack- but this is (the take off)-where my weakness is.:crazy: Did you get good results from your Dr D?

  • grayracer513

Posted October 23, 2007 - 09:27 AM


Put the 8 oz. DRD on it. No question.

  • brandonizr

Posted October 23, 2007 - 09:27 AM


Go with that Dr. D 8oz or equivalent, sounds like it is perfect according to the previous post :crazy:

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