lightened flywheel?

[lefthander12]

Recently while poking around on ebay, I saw a "lightened flywheel" for an ATC 350X. What's the deal with this? Can a competent machinist lighten and balance my stocker? Is it worth the effort and cost? Thanks!

[Wheelie]

According to GT Thunder, it's a waste of money. I thought about having mine done, but decided against it. Do a search, this subject has been discussed several time.

[xxnightraven73x]

the lightening of the flywheel allowns the engine to rev out alittle quicker the less spinning mass is also going to extend engine life alittle by causeing alittle less vibration hope this helps

a true lightened flywheel is worth the money...it makes your motor rev fast and more responsive...having a 2 stroke and 4 stroke lightened in anyway will help a ton, and another thing to look into is getting your motor balanced, that helps out alot too

[cals400ex]

my 400ex was slower when dragging. for a more detailed report search and you will get my whole conclusion.

[boricua]

i asked that question once before to a race team mechanic. his response was that....cars that race on circuits with left and/or right turns requiring shifting and therefore using the one foot on the clutch, the other on the gas and brake....were faster around the track with a lightened flywheel, crank, etc. it allowed the motor to rev quicker in order to get to the right rpm to change gears. it added very little, to no power to the wheels. when drag racing, the heavier flywheel stores more energy. energy that can be used to help create and maintain torque while changing gears. only it revs slower, which doesnt matter much because in drag racing, the rpms only drop when up shifting.

so to conclude, lighter flywheel allows faster spinning motor, with out a load and less torque......and stock flywheel equals slower spinning motor but helps maintain torque......

if you drag......leave flywheel stock
if you race track.....???? could go either way.

[GPracer2500]

Originally posted by boricua
i asked that question once before to a race team mechanic. his response was that....cars that race on circuits with left and/or right turns requiring shifting and therefore using the one foot on the clutch, the other on the gas and brake....were faster around the track with a lightened flywheel, crank, etc. it allowed the motor to rev quicker in order to get to the right rpm to change gears. it added very little, to no power to the wheels. when drag racing, the heavier flywheel stores more energy. energy that can be used to help create and maintain torque while changing gears. only it revs slower, which doesnt matter much because in drag racing, the rpms only drop when up shifting.

so to conclude, lighter flywheel allows faster spinning motor, with out a load and less torque......and stock flywheel equals slower spinning motor but helps maintain torque......

if you drag......leave flywheel stock
if you race track.....???? could go either way.

Wow, nice explination. I don't think I really understood why cals400ex's quad was hurt in the drags. I didn't doubt it, I just didn't get it. But what you say makes a lot of sense.

[cals400ex]

yeah i am not exactly sure either.....i even tried shifting without letting off of the gas. i was still slower than when i do let off the gas to shift using the stock flywheel. the lightened one would not rev as high either. i don't really know but i was noticably slower so i took it off. it seemed the heavier one had more momentum to pull longer and harder. i didn't even notice the lightened one revving any quicker at lower rpms....

[GPracer2500]

Must just not work well on the EX. I'm sure the magnitude of advantages vs. disadvantages of a lightened flywheel varys from one engine design to the next. I bet on the EX the advantage is tiny and the disadvantage significant.

Seems like if it worked well on an EX we'd see more of it. But I don't hear about it being a common mod. So there ya go I guess...

[250r4life]

Originally posted by boricua
i asked that question once before to a race team mechanic. his response was that....cars that race on circuits with left and/or right turns requiring shifting and therefore using the one foot on the clutch, the other on the gas and brake....were faster around the track with a lightened flywheel, crank, etc. it allowed the motor to rev quicker in order to get to the right rpm to change gears. it added very little, to no power to the wheels. when drag racing, the heavier flywheel stores more energy. energy that can be used to help create and maintain torque while changing gears. only it revs slower, which doesnt matter much because in drag racing, the rpms only drop when up shifting.

so to conclude, lighter flywheel allows faster spinning motor, with out a load and less torque......and stock flywheel equals slower spinning motor but helps maintain torque......

if you drag......leave flywheel stock
if you race track.....???? could go either way.

that is a pretty good theory...

yah, lightened flywheels are on the "im not sure how i feel about them yet" list... ive heard several theories, and am still unsure which way i side... same with repacking a two stroke silencer, and a couple other issues...

[boricua]

ive notice a lot of people say, what ever is good for the racing teams should be good for me.......
well, some of that may be true.....but not all. like close ratio gears, theyre great on closed circuit racing and drag racing. so why not put them in our daily drivers........you guys get the idea, im sure. a lot of mods are copied of race teams with out any of the research then later fail only receive a bad name.

here's an example of heavy flywheel..... think of a wood chipper, the kind you see the guys who cut down trees with. they are usually powered by a v8 and sometimes v6 and turn a heavy flywheel to maintain speed when branches are shoved in. it takes a long time for the engine to build speed though, so there is a drawback. but once there, its easier to maintain it.
another, when we were little we played with toys cars that you had to push on the ground over and over, building momentum to get the wheels to turn and then let the car go and it would run across the kitchen floor.....sometimes we would build a ramp and it would climb it, no problem.........

oh, come on.....dont tell me it was just me....haha:p

[buck naked-r]

a lighter flywheel makes you slower in drag racing.

i had one and went to the drag strip to test it and with the stock one the bike was faster.

the one i had also cracked and my crank rod snapped and messed the whole engine up.

if your a MX rider then it may be good,but......tim far was running the crf one and he went back to the stock one so they may not be good for that either.

and because of the possible problems they can cause i would say [stick with stock] there NOT worth it.

[1fst400]

at one point I had one on my 416 motor, It was alright. Realy took off quick out of corners, but the gears went by wicked quick. I ended up swaping back to stock because my motor would not idle with the litened one.

[cals400ex]

with how much slower the light one slowed me down i have thought long and hard about putting a heavier one on to hopefully make me quicker. i am just thinking....lighter=make me slower. will heavier=faster?? i will never know probably. i don't have a bike around here that runs about the same speed as i do anymore. they are either quite a bit slower or a decent amount faster.

[GPracer2500]

I know heavier flywheels are popular on 2 smokers for woods and tight-trail riding. But I think that's more of a rideability thing rather than an outright speed thing.

[cals400ex]

the heavier ones may help prevent stalling for the woods riding too. i guess you said that.....the ridability factor. :D

[st8jacket]

banshee's see noticable improvemennts with a cut flywheel...Also 450r's,go with a crf conversion,to lighten it up a bit...Maybe it just boils down to each individual quad;s engine design and how it is able to rev out,with the wight of the quad......But I think someone mentioned that already....I know in my drag cars we tend to use a aluminum flywheel in the lighter ones like e bodied mopars"70-73 cuda's"and steel ones in the heavier ones....

i had a lightened flywheel on my banshee but then it got damaged (bolt came loose within the stator) and janked up my lightened flywheel so i went back to a regular flywheel and i hate it!

[boricua]

there is a medium of course, like everything else. if you go heavier on the flywheel, then the motor lags a bit while its trying to pull the extra weight, which could require more power. once it spins up, it will be harder to slow down or keep its momentum going (the motor that its). this would make the engine sluggish but a real torquey animal....maybe the 4x4 quads could benefit from that, just a guess.... also probably a good thing for the 2 strokes when in the woods, with low rpm, giving them more low end grunt....something a lot of 2 strokes lack, until you get on the pipe...anyway.
perhaps its easier to look at it this way;

heavier equals more torque, but slow engine response(sluggish)
lighter equals less torque, but more engine response(real snappy)