Losing Weight

Erick
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Erick 2/23/2011 9:04am
2/23/2011 9:04am
By the way, the above is all at your own risk Wink
mattmatt300
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mattmatt300 2/23/2011 9:08am
2/23/2011 9:08am
lighter tires and tubes. spend the rest on suspension and hire a good trainer
Bandito121 2/23/2011 9:36am
2/23/2011 9:36am
mattmatt300 wrote:
lighter tires and tubes. spend the rest on suspension and hire a good trainer
Suspension is done. Getting tired is not an issue. Just looking for ways to lighten it up. How about exhaust? The stock one seems heavy as hell. Is the yosh carbon fiber alot lighter?

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Erick
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Erick 2/23/2011 9:42am
2/23/2011 9:42am
mattmatt300 wrote:
lighter tires and tubes. spend the rest on suspension and hire a good trainer
Bandito121 wrote:
Suspension is done. Getting tired is not an issue. Just looking for ways to lighten it up. How about exhaust? The stock one seems heavy as...
Suspension is done. Getting tired is not an issue. Just looking for ways to lighten it up. How about exhaust? The stock one seems heavy as hell. Is the yosh carbon fiber alot lighter?
Why the exhaust? You are better off saving unsprung weight like mentioned above.
newmann
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newmann 2/23/2011 9:46am
2/23/2011 9:46am
mattmatt300 wrote:
lighter tires and tubes. spend the rest on suspension and hire a good trainer
Bandito121 wrote:
Suspension is done. Getting tired is not an issue. Just looking for ways to lighten it up. How about exhaust? The stock one seems heavy as...
Suspension is done. Getting tired is not an issue. Just looking for ways to lighten it up. How about exhaust? The stock one seems heavy as hell. Is the yosh carbon fiber alot lighter?
Going to a "full" ti DSP SX Racing exhaust on my 2001 YZ250F was almost a three pound weight savings. Now "full" is a bit misleading. All the header, midpipe and muffler canister was ti. The muffler core was steel, end caps aluminum, muffler inlet and outlet stainless and the front mount to the cylinder was aluminum. Made a huge improvement in the low to mid power of the choked up 01 model stainless and aluminum stock system without losing anything up top. Loud doesn't even begin to describe it though.

Is the Yosh lighter? Hell, who knows. None of the companies post the weight of all the trick lightweight stuff.....how retarded is that?
newmann
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newmann 2/23/2011 9:50am
2/23/2011 9:50am
Erick wrote:
Why the exhaust? You are better off saving unsprung weight like mentioned above.
My thoughts on that would be that the exhaust weight is carried up high. Lowering weight up high has a dramatic effect on handling as well as what you are getting at.
level
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level 2/23/2011 10:04am
2/23/2011 10:04am
Erick wrote:
The smartest thing to do to improve your handling by reducing weight is reducing unsprung weight. Unsprung weight is the worst kind of weight on your...
The smartest thing to do to improve your handling by reducing weight is reducing unsprung weight. Unsprung weight is the worst kind of weight on your bike because it is constantly moving and affecting your handling.

Some ideas from the top of my head:

- Lighter tires (tubeless)
- Lighter spokes (titanium)

- CF (Carbon Fibre) chain guide holder and m ake your own chain guide from a lighter material (some spaceshuttle material?)
- CF front fork guards (use plastic bolts to mount them, they are strong enough I think)
- CF rear brake guards (you could also remove them completely)
- CF front brakeline holder (use plastic bolts to mount them, they are strong enough I think)

- Titanium rear axle (don't use titanium front axles, they aren't stiff enough (210GPa vs. aprox. 105-120GPa))
- Titanium linkage bolts/axles
- Titanium shock/fork springs
- Titanium bolts for your brakes

- Aluminium banjo bolts
- Aluminium rear axle nut
- Aluminium rear axle ajuster bolts

Also:
- Steel braided brake lines (they are more efficient than nylon brake lines, so maybe you don't have to use an oversize rotor)
- Machine your brake calipers to make them lighter (there is excessive material to them because of the casting process)
- Machine your rear axle holders to the bare minimum amount of material
- Machine your hubs (the center section COULD be lighter)
- Lighter bearings in your wheels

Zach Osbournes bike, look at the machining of the brake caliper and the fork lugs, simply beautifull


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I would say that's pretty much about spot on and what information your looking for.
Erick
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Erick 2/23/2011 10:39am
2/23/2011 10:39am
Erick wrote:
Why the exhaust? You are better off saving unsprung weight like mentioned above.
newmann wrote:
My thoughts on that would be that the exhaust weight is carried up high. Lowering weight up high has a dramatic effect on handling as well...
My thoughts on that would be that the exhaust weight is carried up high. Lowering weight up high has a dramatic effect on handling as well as what you are getting at.
Hmm I disagree since the place of the exhaust is pretty much at (or very near) the center of gravity on a bike. Making the exhaust lighter will actually put the CG higher on the bike because of the weight of the fuel tank. I must say this is an assumption based on my technical knowlegde so if you can proof me wrong I am very interested.

What I am wondering, what is his main purpose achieve by saving weight? Is it improving the handling? Or is it just saving weight for the sake of saving weight? If he is trying to achieve the first, and since he is considering an Yoshimura exhaust to give an idea of his budget, I think it smarter to spend your money on stuff that actually saves weight on a place where it matters most. In other words: saving weight which is killing your handling. You can get a lot of weight savings if you spend your money in a clever way. This gives a higher handling increasing performance per dollar ratio.
Nerd
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Nerd 2/23/2011 11:07am
2/23/2011 11:07am
gaines1016 wrote:
i post this a lot but. yamaha yz250 is 227lbs wet yamaha yz250f is 224.8 lbs wet now i realize that 2strokers love to argue cc...
i post this a lot but.

yamaha yz250 is 227lbs wet
yamaha yz250f is 224.8 lbs wet

now i realize that 2strokers love to argue cc for cc when it comes to hp but when you bring up things like this they want to compare 250f's to 125s.
txmxer wrote:
glad you posted that. yz250f gas tank: 1.7 gal yz250 gas tank: 2.1 gal wet weight without gas (~6 lbs/gal) yamaha yz250 is 214.4 lbs wet...
glad you posted that.

yz250f gas tank: 1.7 gal
yz250 gas tank: 2.1 gal

wet weight without gas (~6 lbs/gal)

yamaha yz250 is 214.4 lbs wet (no gas)
yamaha yz250f is 214.6 lbs wet (no gas)

Evil

"you really should have known" DBM
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much less circulating mass in the engine, so regardless of actual pounds of weight, the two-stroke will feel lighter anyway.
newmann
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newmann 2/23/2011 11:23am
2/23/2011 11:23am
Erick wrote:
Hmm I disagree since the place of the exhaust is pretty much at (or very near) the center of gravity on a bike. Making the exhaust...
Hmm I disagree since the place of the exhaust is pretty much at (or very near) the center of gravity on a bike. Making the exhaust lighter will actually put the CG higher on the bike because of the weight of the fuel tank. I must say this is an assumption based on my technical knowlegde so if you can proof me wrong I am very interested.

What I am wondering, what is his main purpose achieve by saving weight? Is it improving the handling? Or is it just saving weight for the sake of saving weight? If he is trying to achieve the first, and since he is considering an Yoshimura exhaust to give an idea of his budget, I think it smarter to spend your money on stuff that actually saves weight on a place where it matters most. In other words: saving weight which is killing your handling. You can get a lot of weight savings if you spend your money in a clever way. This gives a higher handling increasing performance per dollar ratio.
Far be it for me and my high school education to get into a pissing match with anyone who has technical/engineering background.Smile Not disagreeing with you in the least as everything you stated makes good sense. But modern 4 strokes have huge ass mufflers and that bolt on way up high at the seat mount. That's the bulk of the exhaust system weight as some current bikes already have ti headpipes on them.

There are certain areas where my 4 inch travel vintage bikes handle better than a modern bike (whoops wouldn't be one). Why? My guess would be because it sits lower.

Questions for you though about the titanium springs. Are they sprung or unsprung weight? Or 50/50? And does that differ from the front springs (spring /singular on his 2011 KX250F) to the rear shock spring?
UpTiTe 2/23/2011 11:23am
2/23/2011 11:23am
I saved about 2 pounds on my daughter's bike by useing Ti spokes, nuts and bolts. I got all the stuff for free but the wheel set alone retailed for 580, so yeah, Ti parts are pricey.
TooOldToPlay
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TooOldToPlay 2/23/2011 11:45am
2/23/2011 11:45am
The weight comparison numbers between the YZ250 and YZ250F still sort of amaze me, as it suggests, that if the rolling chassis (sans motor) are basically equal, that the four stroke motor (and all it's moving parts) actually weighs basically the same as the less complex two stroke motor. Probably just me, but that still seems hard to believe.
xnationalwrench 2/23/2011 11:53am
2/23/2011 11:53am
xnationalwrench wrote:
Stop drinking beer and stay away from fried foods.
mattmatt300 wrote:
this^

most people could lose 10 pounds in a month. it would cost a chunk to take 10 lbs off a bike.
Bandito121 wrote:
At 140lbs I dont think losing 10lbs a month is an option. Anybody have any real suggestions. I know its not cheap, but willing to spend...
At 140lbs I dont think losing 10lbs a month is an option. Anybody have any real suggestions. I know its not cheap, but willing to spend some money. So where do I start.? Dealing with a 2011 KX250F.
Sorry but I wasn't trying to be a wise guy. May I ask are you doing this for a racer or a show bike? If a racer some things that will make the bike stronger will add weight and using pieces that weigh less means replacing them on a regular bases. BTW you still are about 10 or 20 pounds heavier than many of the 250 pros (and Alessi 2).
burn1986
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burn1986 2/23/2011 12:16pm
2/23/2011 12:16pm
Totally good article Newmann. If MXA lost 17 obs on a CRF250, imagine how much you could lose on a 125, or a 150, heck, even a 250. Can you imagine losing 17-20 lbs on a 125 or 150? That would almost be worth the money.
ATKpilot99
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ATKpilot99 2/23/2011 12:19pm
2/23/2011 12:19pm
burn1986 wrote:
Totally good article Newmann. If MXA lost 17 obs on a CRF250, imagine how much you could lose on a 125, or a 150, heck, even...
Totally good article Newmann. If MXA lost 17 obs on a CRF250, imagine how much you could lose on a 125, or a 150, heck, even a 250. Can you imagine losing 17-20 lbs on a 125 or 150? That would almost be worth the money.
Sometime in the 90s Dirt Bike or MXA, can't remember which built a 167 lb. CR 125.
burn1986
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burn1986 2/23/2011 12:20pm
2/23/2011 12:20pm
I know, I need to find it. I'll keep looking.
newmann
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newmann 2/23/2011 12:29pm
2/23/2011 12:29pm
ATKpilot99 wrote:
Sometime in the 90s Dirt Bike or MXA, can't remember which built a 167 lb. CR 125.
1994 Dirt Bike Magazine, Terry Good from On the Line Racing / 911 Race Shop built that and DeCoster tested it .....in the mud. Unfortunately it rained that day! Friend of mine owns that one now, Bill 163 here probably knows which garage it's in.Evil

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burn1986
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burn1986 2/23/2011 12:37pm
2/23/2011 12:37pm
newmann wrote:
1994 Dirt Bike Magazine, Terry Good from On the Line Racing / 911 Race Shop built that and DeCoster tested it .....in the mud. Unfortunately it...
1994 Dirt Bike Magazine, Terry Good from On the Line Racing / 911 Race Shop built that and DeCoster tested it .....in the mud. Unfortunately it rained that day! Friend of mine owns that one now, Bill 163 here probably knows which garage it's in.Evil
Paging Bill 163... How cool it would be to have a current day test. I am amazed at your connections Newmann. Are you sure you're not an industry insider?Cool
txmxer
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txmxer 2/23/2011 12:40pm
2/23/2011 12:40pm
TooOldToPlay wrote:
The weight comparison numbers between the YZ250 and YZ250F still sort of amaze me, as it suggests, that if the rolling chassis (sans motor) are basically...
The weight comparison numbers between the YZ250 and YZ250F still sort of amaze me, as it suggests, that if the rolling chassis (sans motor) are basically equal, that the four stroke motor (and all it's moving parts) actually weighs basically the same as the less complex two stroke motor. Probably just me, but that still seems hard to believe.
as pointed out, the chasis are not the same. I don't have numbers, but I'd bet the 2 stroke sans engine would be heavier.
gaines1016
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gaines1016 2/23/2011 12:43pm
2/23/2011 12:43pm
gaines1016 wrote:
i post this a lot but. yamaha yz250 is 227lbs wet yamaha yz250f is 224.8 lbs wet now i realize that 2strokers love to argue cc...
i post this a lot but.

yamaha yz250 is 227lbs wet
yamaha yz250f is 224.8 lbs wet

now i realize that 2strokers love to argue cc for cc when it comes to hp but when you bring up things like this they want to compare 250f's to 125s.
txmxer wrote:
glad you posted that. yz250f gas tank: 1.7 gal yz250 gas tank: 2.1 gal wet weight without gas (~6 lbs/gal) yamaha yz250 is 214.4 lbs wet...
glad you posted that.

yz250f gas tank: 1.7 gal
yz250 gas tank: 2.1 gal

wet weight without gas (~6 lbs/gal)

yamaha yz250 is 214.4 lbs wet (no gas)
yamaha yz250f is 214.6 lbs wet (no gas)

Evil

"you really should have known" DBM
Nerd wrote:
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much...
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much less circulating mass in the engine, so regardless of actual pounds of weight, the two-stroke will feel lighter anyway.
that is correct. leave a half a gallon of fuel out of the 2stroke and they are almost identical weights (for the yamaha anyway). all i was pointing out with those numbers is how close they are in reality. "feel" is subjective but the reasoning is sound and 9 out of 10 may say the 2 stroke feels lighter however i think they feel a hell of a lot closer then what many vital posters lead people to believe.

but once again i let myself get drawn into this 2vs.4 business and this time in a thread where there wasnt even a question about a 2 stroke motorcycle. back to your regularly scheduled thread.
burn1986
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burn1986 2/23/2011 12:55pm
2/23/2011 12:55pm
There's a lot of subjective stuff, but lighter is lighter. I could go faster and get less tired out on a lighter bike.
gaines1016
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gaines1016 2/23/2011 1:13pm
2/23/2011 1:13pm
burn1986 wrote:
There's a lot of subjective stuff, but lighter is lighter. I could go faster and get less tired out on a lighter bike.
seems a bit over simplified but i'm glad you have found a bike you enjoy and suits your riding style.
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Clotskull 2/23/2011 1:13pm
2/23/2011 1:13pm
Nerd wrote:
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much...
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much less circulating mass in the engine, so regardless of actual pounds of weight, the two-stroke will feel lighter anyway.
WRONG.
newmann
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newmann 2/23/2011 1:27pm
2/23/2011 1:27pm
Chili wrote:
So back to the earlier topic of Ti fasteners, they spent $6230 in Ti to shave 3 pounds off the bike. Yikes!
Yes, when $1000.00 worth of springs or $200.00 worth of Michelin S-12 sand tires or a $800.00 exhaust will do the same. Those last few pounds are what get expensive.
burn1986
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burn1986 2/23/2011 1:38pm
2/23/2011 1:38pm
gaines1016 wrote:
seems a bit over simplified but i'm glad you have found a bike you enjoy and suits your riding style.
Of course, I'm still looking for the ultimate XR200.
DMG
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DMG 2/23/2011 2:31pm
2/23/2011 2:31pm
Erick wrote:
The smartest thing to do to improve your handling by reducing weight is reducing unsprung weight. Unsprung weight is the worst kind of weight on your...
The smartest thing to do to improve your handling by reducing weight is reducing unsprung weight. Unsprung weight is the worst kind of weight on your bike because it is constantly moving and affecting your handling.

Some ideas from the top of my head:

- Lighter tires (tubeless)
- Lighter spokes (titanium)

- CF (Carbon Fibre) chain guide holder and m ake your own chain guide from a lighter material (some spaceshuttle material?)
- CF front fork guards (use plastic bolts to mount them, they are strong enough I think)
- CF rear brake guards (you could also remove them completely)
- CF front brakeline holder (use plastic bolts to mount them, they are strong enough I think)

- Titanium rear axle (don't use titanium front axles, they aren't stiff enough (210GPa vs. aprox. 105-120GPa))
- Titanium linkage bolts/axles
- Titanium shock/fork springs
- Titanium bolts for your brakes

- Aluminium banjo bolts
- Aluminium rear axle nut
- Aluminium rear axle ajuster bolts

Also:
- Steel braided brake lines (they are more efficient than nylon brake lines, so maybe you don't have to use an oversize rotor)
- Machine your brake calipers to make them lighter (there is excessive material to them because of the casting process)
- Machine your rear axle holders to the bare minimum amount of material
- Machine your hubs (the center section COULD be lighter)
- Lighter bearings in your wheels

Zach Osbournes bike, look at the machining of the brake caliper and the fork lugs, simply beautifull


Uploaded with ImageShack.us
You must have DEEEEEEEEEEEEEEP pockets to afford what youre talking about. Who intheir right mind that isnt lining up on saturday nights would need all that stuff?
rmpilot
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rmpilot 2/23/2011 2:40pm
2/23/2011 2:40pm
Nerd wrote:
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much...
Not only that, but the truth of the "weight" thing is that a two-stroke FEELS lighter (which is really the point) mainly because there is much less circulating mass in the engine, so regardless of actual pounds of weight, the two-stroke will feel lighter anyway.
Clotskull wrote:
WRONG.
how is that wrong?
Craig_Lambrecht 2/23/2011 3:00pm
2/23/2011 3:00pm
xnationalwrench wrote:
Stop drinking beer and stay away from fried foods.
mattmatt300 wrote:
this^

most people could lose 10 pounds in a month. it would cost a chunk to take 10 lbs off a bike.
ahh mannn! two of my favorite things!

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