flywheel affects?

My 426 is very testy in the slower corners with stalling. I am thinking about getting a heavier flywheel to prevent my 2001 426 from stalling in tight trail riding. My question is how the flywheel will affect the throttle response? I think I would like it if it smoothed it out and prevented it from hitting so hard, but not sure if that is what it will do? Also, how heavy is the factory flywheel and how heavy should I go with a new flywheel? Thanks.

I never added a weight to my bike when I had it because I rode motocross with it. Also after installing an autodecompression is actually possible to bump start the bike if you stall it (stall it going hot into a corner and all it takes is to let the clutch back out if your still moving and the bike will come to stock form the 426 would slide to a stop! LOL).

Most of the woods guys use 8oz flywheel weights. It will lessen the tendency to stall and smooth things out. If you geared the bike correctly, added a weight and the DCM you would rarely if ever stall.

I put the Dr. D 8 oz on my 04 450 about a month ago. I only have 2 rides (MX) on it so far but I really like it. It doesn't stall nearly as easy and it smooths the power out also which makes it easier to ride for me. I feel like I could easily ride it in the woods if I wanted to. Right now I'm running the 14T front sprocket but I'm going to try the 13T. I need a little more torque coming out of corners. Relatively cheap (if you send back the stock flywheel) and easy mod to do.

Are 4 strokes easier to stall than a 2 stroke......generally? I mean, I never stall my 2 stroker, but can I expect stalling issues with my new YZ450F?

Coming off a 2 stroke you should be ok. I have always had XR's which are very easy to keep from stalling. It took me awhile to get used to the YZ450 and I still stall it every now and then.

Regarding the 426 and flywheel results for woods riding, definitely add the flywheel weight. For general hare scrambles speeds go with the 10 oz. and for enduro tight single track go with 12 oz. The engine will still run fast but you'll significantly reduce the stalling. A side benefit is a little bit better starting with the heavier flywheel effect.

Steahly Offroad sells a complete Yamaha OEM flywheel with the additional weight mounted for around $150 (don't quote me) if memory serves correct. Best money you'll spend for offroad on that model.

Where a 250 2 stroke shines over a 426/450 is in that nasty rocky trail condition when you're at a low rpm picking your way thru at a very slow speed. That's one place a flywheel weight helps out.

Go ahead and add the weight, you will never look back, I added the heavier of the two flywheel weights Yamaha (GYT-R) have to offer for my '05' YZ450 and still can't believe the difference it has made. Definately smooths out the power, infact it adds a little more torque/traction to the bike, in effect making the bike less 'snappy' off the bottom. The extra weight also adds that needed engine enertia to carry you through those tighter single track corners, perfect for those rtcb rides around the south east corner QLD .............

I'd have to agree with Muddza regarding the increase in traction.

I got a used Stealthy 16oz off of a guy in AR. At first thought, I was just a bit concerned that I had never heard of anyone installing a flywheel this heavy.

My concerns with the heavy weight were unfounded. I noticed I'm not as tired after a woods ride. But the craziest thing I feel after putting that big weight on the crank is the gain in traction and lugability-keep in mind I've got a Rekluse as well.

Before, I'd pin it and the back tire would seem to spin for a split second, then the bike would move. But now, I pin it, and it seems to go. It dosen't seem to be one bit less snappy.

After the first time out in proper woods, I came back with a big grin, shaking my head in disbelief at the blue beasts new manners.

My bike has gone from an ill-behaved 13 year old to a sure footed Mountain Goat in 20 minutes.


Are flywheels easy to install???? :thumbsup:

Provided you have a flywheel puller then yes, but for the cost of one of these, Yamaha can have it fitted in half the time and you'll have a little hard earned left over for a few cold ones at your local........

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