Fly Wheel Wieghts for YZ450

Never been so confused. Was going to go with Dubcchs weld on option. Four or sex. Then talked to some local shops and they don't recommend it. Problems with the ceramic coating being welded on and other problems. They recommend TY Davis's cure. Complete fly wheels. The shop recommended a 10 oz which according to Dr. D's people is way to much. With Tys system you can easily change the weight. Dr. D according to his people runs a 4 oz. but then he probably has new tires all the time and is on nicely groomed tracks, not the blue groove thacks of Lake Elsinore. Anyone have any info. Never had a stalling problem, just the bike has so much power and wheel spin, that it doesn't hook up like the Honda CR450 does. But I still would only ride a Yamaha YZ450. Hopefully the 10 oz will allow the bike to hook up.

I'd check with Steahly ( ). Every aftermarket segment has a leader, for flywheels it's Steahly. ( Ty doesn't built anything he gets his from Steahly!) Being able to change weights would be nice...but welded is well WELDED. Done right it's not going to come lose! :D

Dr. D has more test time on the YZ's than any guy on the planet. I wouldn't hesitate to buy anything for a YZF from him. If you're concerned about the welding ask them about it... Please post their responce. I'll bet they tell you if it comes apart they'll make it right! :D

Let us know which way you go and how it works out. This is one of the first mods my bike will soon as I get one :)

I have talked to his niece and some other lady who works in his office. The local shop here in So. Cal. was saying if the weight comes off it will gernade the engine. I will call Stealthy tomorrow and Dubach racing. Just to add to the confusion. Thanks for trying to help. Dubach's people are saying don't go with much more than a 4 oz to a max of 6 oz.. The others are saying 10 oz. What a range. Maybe I will go to Dubach's place also. He shares the same small office as Enzo Racing in Santa Ana Calif.. Enzo does suspension.

If I am not mistaken, with the bolt on type systems you need a spacer between the cover and case for clearence, but with a weld on you dont. Is this correct?

I don't know. I am not going to do anything for awhile except ride ride ride.

The local shop here in So. Cal. was saying if the weight comes off it will gernade the engine

I've NEVER heard of a PROFESSIONALLY installed Flywheel weight coming apart. :D Sounds to me like the shop may have an agenda?


I agree. Sounds, like they just want to sell whether it is good or not.

I might mess around with the rear sproket (from 48 to 46) and some suspension work (Enzo) the larger (120) rear tire and then throttle conrtol. I bought the bike for the burst of power, I don't ride in the woods or trail ride. Strictly tracks. As it sits, stock the bike is more like a 2 stroke 250 according to others. I had a Honda CRF450 with lots of extras. Nice bike, just doesn't have the hp and explosiveness that the YZ does. Plus the YZ corners, and tracks so much better.

I think we're on the same path! :) I didn't care for the CRF handling. The more like a YZ250 they make it, the better I'll like it! :D

I have the Terrycable bolt-on flywheel and yes, it does have a spacer. About 4-5mm thick blue anodized aluminum. Looks trick.

I have the 6oz. I went with the bolt on style because I like the idea of having the option to change easily, even if I don't. The weights are spendy for what they really are.

Yamaha is making a flywheel weight for the 450F that will be available in late February or early March. It is approximately 5 ounce and is used by the MX team. One nice thing is that Yamaha backs their parts. I had previously posted the part number, but the message got deleted. I'll try to post it tomorrow.

Hey vintageyz,

Where did that tidbit of info about Yamaha developing their own flywheel weight come from? That's awesome if they are but I did a search and found nothing. I was going to get a Dubach 4 oz. in a couple of weeks but if I can confirm that Yamaha is going to sell an over the counter remedy I may wait.


I have a Steahly 10oz on my 450. Dr D can send you one already mounted and when you get it you send yours in (no down time)or he can use yours. When I called him he was out of cores and I was afraid of a lengthy down time. I also sent him some info on email about me and the riding I do to see if he suggested the 6 or 8oz. He never responded. I've always used Steahly in the past so I ordered a 10 oz from them. As far as the weights go, consider this. The amount of weight is not as important as where the weight is. How much heavier does a 1 pound weight on the end of a 1' string feel compared to a 3' string when the weight is swung? The Dr D is a ring mounted on the exterior, giving it a better inertia advantage. The Zip-Ty is bolted on but carries the majority of the weight towards the outer and the Steahly uses the Flywheel nut and has the most weight in the center of the shaft. I can't do the complicated math on it but I think the Steahly 10oz would be comparable to about 9 oz mounted like a Zip-Ty and about 7 oz mounted like the Dr D. For pure M/X I would recommend the Dr D 4oz, for fast off roaders/other M/Xrs, the Dr D 6, or Zip-Ty around 9oz, for less skilled mechanics, amt/nov off-roaders the Dr D 8, or the heaviest weight you can find from Zip-Ty (must be comfortable with taps) or Steahly (If you lose a drag race it will be your fault not the weight). I have mounted the Zip-Ty on 426s and think its the best mounting system. It takes the longest and is the most complicated though. They don't realy tell you how to tap (you have to back the tap out to clean out the metal every time you make a 1/4 turn in) so I fear there are a lot of poorly mounted weights out there. You have to watch the inside of the weight and make sure you get all of the metal out also. The Steahly is the easiest by far. I was scared of the liitle set screws backing out but noticed they have crimped the ends so they can't even if they come loose. Don't EVER back these screws all the way out. I checked mine after a few hours and everything was just as tight as when I installed it. Hope this helps. I ride expert (In Texas this is under Pro) off-road and Int M/X. I like the 10oz Steahly, its a good compromise for M/X and off-road. If I rode just off-road, I think I'd like a little more.

Going to go with the 4 oz from Dr. D. Will take it off Sunday and take it to his shop on Monday. Usually the girl in the office said they take the flywheels on Tuesday and Thursday if they have enough. Talked to other YZ450 owners and the concensus seems to be the Dr. D. Since I ride strickly track don't want to lose to much of theat awesome power. Just want to improve the trackability of the bike when on slippery dry/wet tracks. Already have a puller. I will try and let TT community know how it is.

I put the 4oz. Dr. D on mine. I really like it alot. I ride B class and I can notice a difference and I am only riding on Arenacross tracks right now. Some can't notice a difference. It depends on how well you know your bike. But I can garentee(poor spelling) if you run the 10oz and race MX your going to feel slow.

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