YZ250 Custom Flywheel Weight- Part 8- Project Build
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- čas přidán 13. 09. 2024
- I've thought about building an "enduro" sized flywheel weight for a YZ250 for years. This project was the perfect opportunity.
I'm totally attacking this from scratch and I have no idea if it will be good or a complete waste of time & effort.
What I can tell you is that I'll test it thoroughly and share the results. - Jak na to + styl
The radius of the flywheel is more important than the overall mass to conserving inertia because inertia of an object squares with the distance from it's axis of rotation.
mad scientist at work - impressive workshop engineering👍
Ur gonna be ready to do some trials type wind ups with that thing super cool Chuck!
Excellent demonstration of how much goes into designing and fabricating a "relatively" simple part, the flywheel weight. Everything is easy we think, until we do it and find out how many things are involved. Thanks!
VERY INFORMATIVE VIDEO ,LOTS OF TRIAL & ERROR =MUCH TIME . BACK IN THE DAY I USED A FLYWHEEL FROM A OLDER MODEL (1989)CR250R ON MY 1992 FOR MX .IT WAS ONLY 4 OUNCES HEAVIER BUT HAD ALL THE ADDED WEIGHT ON THE OUTER DIAMETER. TWAZ MUMMY BEARS PORRIDGE. REALLY MADE THE BIKE DRIVE OUT OF CORNERS & TRACK STRAIGHT ESPECIALLY ON ROUGH TRACKS
If you know even a little bit of how to use an 3D modeling software, you could 3D-print test pieces to see if it fits. Way cheaper and probably less time involved like so. After seeing the part fits you can just machine the part without having to do the actually hard work all over again. Great project however and it seems like you're a man with many talents! Subscribed with thumbs up. 👍
I can use Tinkercad a little bit. Not my forte though.
Years ago I played with the same ideas on my then new 1979 Can-Am . I found out the hard way that any rotating mass secured with a key had not only to deal with forces of acceleration but deacceleration . A hard application of the rear brake and slow on the clutch played hell with the weakest link, the key. There are reasons why flywheels do not exceed certain design limits .
The key should only be an alignment reference. If the taper is done accurately and the nut is tight there should be zero stress on the keyway. Trials bikes also have much bigger flywheels than this.
@@ChuckfromTrueTech Really like your videos mate.
I have a CR500 that I had converted to a 250 ignition and flywheel, I loved the free and snappy engine response. I then installed an electric start unit, it has the heavy CRF450 flywheel. Man I hated that flywheel, it really dulled the power response and made the front end push through the corners worse.
I then went about removing weight from any other spinning items I could. Aluminium clutch plates instead of steels, Titanium clutch bolts, Ti front sprocket bolt, Ti rear sprocket bolts, Ti rear disk bolts, changed the steel rear sprocket to aluminium, tubeless rear tyre system and a low drag chain. All these combined really did help to get the engine snappier, although I'm used to it now I still believe it has a negative affect on cornering. My point to this is, if it affected a 500cc engine so much I would guess it would really impact a 250.
The aluminium clutch plates and the aluminium rear sprocket made the biggest changes. But because the clutch spins backwards, reducing it's weight cancels out less of the cranks enertia, thus keeping the front push.
i just got in on this project. Have you thought about clutch weights. Also i learned fron Rekluse that the clutch on a 2022 crf250r spins alot faster than the basket on a Husqvarna te300i. So the difference in badket speed of ktm brands probably contribute to why they track so well and dont stall or flame out as easy. Flywheel weight would be my first project also but the heaver you hget it the more stress you put on the seal and crank bearing in that side. You could machine you a flywheel cover spacer so you could make a fly wheel thats thicker and flares out past the clutch engagement arm then you could go as big as you want. when all is done look at getting the flywheel ballanced. looking foward to the outcome
I’ve seen clutch weights wiggle loose too many times. Can’t trust them.
I’m not sure why people think a bigger flywheel will stress the bearing & seal. The weight is machined very accurately, so it shouldn’t have a balance issue anywhere near the inconsistency of the piston & crank on a non-counter-balanced engine. Not to mention that counter-balancers don’t wear out bearings prematurely. I have no worries.
I would consider hiding clutch weights inside the inner hub or on the back of the basket somewhere if they could be mounted securely, but since the clutch spins slower than the engine the flywheel is my first choice.
Nice job. I usually 3d print my parts first in plastic. After several versions and improvements then Ill move to metal. Saves a lot of time and headaches. Id like to make some adjustable versions so you can easily swap weights.
That will be pretty easy actually now that there’s a CAD file.
I'm waiting to see how it changes the engine behavior...
Love this!!
So basicly a heavier flywheel will reduce you’re wheel from spinning like crazy and giving you no traction? Someone correct me.
Just fyi when you cut down the flywheel to reduce the OD that wasn’t a boring operation.
Lol. Well technically it was a turning operation. 🤣
Looking forward to seeing how it works! Curious on loading the flywheel and dropping the clutch how it’ll feel.
If the flywheel got big enough I suppose it s possible the clutch springs would need to get upgraded to stiffer ones ?
No, does not change the overall power just the responsiveness.
you sould buy a 3d printer eaven with little knowledge they are super useful for prototyping
I have actually purchased one recently. My kids are learning to use CAD. I’m getting them to design stuff for me.
Is this flywheel for sale? And how much would it be? Thanks lmk
I could have one made for you if you want one I suppose. Send me an email. chuck@truetechmc.com
Great work and I know several people that would purchase one from you if you decide to go that route. Curious, is the YX250x the same or does it come stock with a heavier flywheel?
Since the final one was done via CNC I can provide them for anyone that wants one.
The X is the same. Tested this on a stock one last summer.
@@ChuckfromTrueTech Sending a friend your direction. He has a steel framed YZ setup for PNW woods and it works well.
a 21oz flywheel weight is crazy considering that the largest one that steahly makes is 13oz. personally i dont even like the 13oz one. im more of a fan of the 7oz or 9oz ones but i cant see for a more technical style of riding how it would be beneficial. i have my beta for the hard stuff
I tested with different motor setups. Massively different feel. Can’t spoil the surprise though. I’ll report soon.
Can't put it on a lathe and turn it down to be heavier. It's better to start heavy and work back than have to make a whole new part.