Flywheel Shaving, Ups and Downs?

[Drfat400ex]

So I've been doing some reading in times of bordom lately and have came to discover that you can go though the gears quicker with a lightened flywheel. But somewhere I read that a heavier flywheel is better in the trails when your wheels are getting bogged down. What's the good and bad things about lightening a flywheel and please explain. I'm a trail rider, never been at an mx track but I'm planning on going for fun sometimes and I drag race my buddies a bit too, hills, small jumps, lots of fast curvy trails but also tight muddy ones. Thanks guys.

[CJM]

Honestly it doesnt need to be done on the EX. You want it heavier for trail riding, otherwise it can stall too easy (as is the case with some 450rs if your not careful).

I thought I wanted to do it, until I did the hi-comp setup and it all but eliminated any issues I would ever seem to have with the flywheel. Mine races up so easy its not even funny.

[Drfat400ex]

Haha man you're always there with the perfect info CJM. Thanks.

[Duf6]

I love my shaved flywheel, it never really did seem to stall any easier but i try not to let it get bogged down much.

[Wheelie]

I installed a lightened flywheel over a year ago and wish I would've done it sooner. Tremendous improvement in the overall character of the motor. The quad revs much quicker, transitions into the 'meat' of the power much better. Stalling is not an issue, it took me about 5 minutes to adjust to the change. I can still let the clutch out in 1st gear without touching the gas and the quad won't stall....on flat ground.

IMO, do it, you won't regret it. I've found zero negatives to a lightened flywheel and many positives. The stock EX flywheel is HEAVY. Even after shaving 12 ounces off it it, it's still heavier than a stock 450r flywheel.

[CJM]

Wheelie, how fast does yours rev up? Since doing the 450r carb mines revs insanely fast-1st and 2nd are darn near unusable in most situations and Im already geared down to to 37T rear to stretch the gears more.

[Wheelie]

1st and 2nd are insane. 2nd gear on anything but asphalt is topped out nearly instantly. It revs pretty damn fast.

[CJM]

Originally posted by Wheelie
1st and 2nd are insane. 2nd gear on anything but asphalt is topped out nearly instantly. It revs pretty damn fast.

Thats pretty much where Im at. Whats was once a 2nd gear jump or riding area is 3rd/4th gear in some cases. I like it, but Im running outta gears lol.

[xcracer416]

who is a reputable person to lighten a 400ex flywheel? also how much does it cost?

[Stickman400]

I feel about the same way CJM. After that 450R carb. mine revs insanely quick, almost too quick. Jumps on my little practice track that I hit at about half throttle in 2nd gear I now have to hit damn near topped out in 3rd. It's ridiculous. I'm gunna put a 36t in the rear along with my 15t up front and see if that helps out any.

[400man]

mine has a lightened flywheel and with my yfz450 carb it feels like it revs almost like a 450, really quick and snappy and it pulls through the revs great. im geared 14/36 with 20inch rear tires and I have ZERO problems with stalling in the woods. if your a somewhat aggressive rider you will love a lightened flywheel.

[chevymanrick]

Who did Yall use to shave the flywheel down? How much did it run you?

[Thumpin440ex]

I believe it is about 75 buks or so. I have read of the bogging issues with them, but like the idea of the faster revs to pull the rpms. It is something I would like to try one day.



John

Originally posted by CJM
Since doing the 450r carb mines revs insanely fast-1st and 2nd are darn near unusable in most situations and Im already geared down to to 37T rear to stretch the gears more.

please help,i'm not following the my quad is snappy with tons of torque,too much almost,so i put shorter gears on it to try to balance it out?are you saying 1st and 2nd WIND OUT so quick they're not even usable?if thats the case a taller rear,or front for that matter would give you less torque and therefore more room/length/time in each gear,correct?for every rotation of say a 15t front a 37 rear will rotate,lets say less than half a turn.a 38 will rotate slightly more and a 39 will rotate the furthest of the 3.more rotation gives you more distance equalling speed and length of time per gear.not trying to pick on anyone and you arent the only one that said it,think i just prefer your answers better most of the time so im quoting you.sorry just not following here is there something i missed or misinterpreted?thx

[CJM]

Heres the deal with gearing: Going up in the back gives more torque, going down gives speed. its the opposite for the front, up is speed, down is torque. For every 1 tooth in the front its equal to 3 in the back.

In my case I am already running a 37T rear and 15T front. 1st is near unusable-it winds out WAY to quick and 2nd is better but not great. I had had the same problem with 15/38, so I went to 15/37 and was happy, doing some more mods (mostly the 450r carb) and its back to the way it was before I dropped a tooth.

What I need to do is give myself longer gears, more speed. Thus I either need to do a 16T front (done before the carb and I hated it..no torque) or go down in the rear another tooth to 36T. It doesnt seem like much, but it adds just that little bit that (least in my case) you need to regain a good gear setup. Where your gears arent to long or to short.

What happens now is I take off and 25ft later 1st is done..2nd is done pretty much the same, 3rd is better and is the rest but you kinda run outta gears this way. When I was going fast on trails Id wind out 2nd or be in 3rd alot lugging, now Im flying in 3rd/4th all day.

yea i had to read that again and think about it more but i stand corrected.not sure why it just wasn't registering.went out and looked at the adjustable pulleys on an old mill and drill press we had and yea.not sure why i was thinking a taller rear would offer more speed as well as a taller front.sorry and thx for the reply.i'm gonna go hang my head in shame now.

[CJM]

Dont beat yourself up over it man. took me a long time to know all this stuff lol.