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02-05-2013, 11:01 PM   #32956
pfy50
Professional nOOb

Joined: Aug 2006
Location: Oneida, Tenn.
Oddometer: 577
Quote:
 Originally Posted by avgas A bicycle/motorcycle can be thought of as an inverted pendulum regardless of whether or not the rider is standing. Standing will increase your moment of inertia however. An increased moment of inertia can be beneficial because it slows the rate at which you tip over. Think of a metronome, you raise the weight and it ticks a slower beat. So, if it takes you longer to tip over, it's easier to correct. You can easily balance a broom on one finger, because you have lots of time to react. A pencil is much harder to balance though. Actually, that's not a perfect analogy to the bicycle, because the pencil is much lighter than a broom. Ok, balance a broom on your finger, then cut off the broomstick... It isn't really as simple as that though. A rider balancing a bicycle is a complex system. The inverted pendulum is just one part of it.
Can I get in on this.
Here's my 2cents. It is 2 different problems you are talking about; COG and Momentum/inertia. The simple answer to the original problem of standing/stability is this: Every vehicle has a static center of gravity(cog) usually on a motorcycle it's just behind the engine and below the center of the seat(you feel it as how the bike balances. When you sit on the bike you move that COG higher toward the point of contact(you're butt); this called the effective COG.The higher the effective cog the tippier the bike feels; like when you fill up one of those aftermarket tanks(which is why they try to put as much as possible down low(wings). When you stand on the pegs for sand or ruff roads your mass goes up, but your point of contact with the bike is the foot pegs so your weight goes there(when you stand on the ground all of your weight is on your feet correct?) When your weight is on the pegs the effective COG is lowered hence the increase in bike stability. Which is what you want in crossing ruff and soft terrain. When you lean forward/back going up/down a hill, and weighting from side to side then you are changing the effective COG with mass(weight within gravitational field) &velocity=(Momentum), and this is where momentum and inertia (along the 3 axis of the bike) get involved as you attempt to maintain a balance between you, the bike, and the terrain you are traversing.
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2013 TEX XC,2011 WR250R,2004 KAWA Concours,1994 BMW K1100RS
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02-05-2013, 11:27 PM   #32957
skierd
Wannabe Far-Rider

Joined: Jan 2008
Location: Fairbanks, AK
Oddometer: 2,938
Quote:
 Originally Posted by avgas Anyone out there not use a radiator guard and regret it? I'm considering one, but I'm cheap... err, I mean, I'm concerned about cooling.
I've done a lot of nasty shit to my bike, but overheating has never ever been a problem. Not even loaded up on the TAT in 100+ degree heat on sandy trails, not in 100+ heat and nearly as high humidity running 1st and 2nd gear through the woods on tight single track back home in Maryland. I have dropped it a LOT however, and often on the right side. The radiator guard is good to have.
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"We wish your trail a long one" - Darlene "Sid" Dowd ~ Never run out of traction, ideas, and real estate at the same time.
2008 Yamaha WR250X
Eastern TAT 8/2009 ~MD-Key West-Oklahoma 4/2011~Maryland to Alaska 3/2012

 02-05-2013, 11:31 PM #32958 Joe Watson Beastly Adventurer     Joined: Jul 2008 Location: Sunshine Coast, Qld, Aus. Oddometer: 1,031 Hey, Check out my vid of my WR250R before I sold it: __________________
02-06-2013, 02:26 AM   #32959
rsteiger
Bob

Joined: Jul 2011
Location: Hotlanta Area
Oddometer: 213
Quote:
 Originally Posted by z@ch You don't need a stabilizer. When you ride in the sand: 1. Stand up. It lowers the center of gravity and stabilizes the bike. 2. Stay on the gas. It shifts the weight to the rear and allows the front to "float" across the sand. 3. Steer with the pegs. In deep sand, shifting weight to the right peg with help you steer to the right and vice versa. Comfort comes with experience. True knobbies don't hurt either.
Z@ch is right, you don't NEED a steering stabilizer.

I to went through aquainting myself with riding in sand even on my DL650 V-Strom in street tires. Everything he said is true. Except standing up does NOT lower the center of gravity it INCREASES the moment of intertia which makes the bike less likely to change direction from a given input - think of a figure skater with her arms out and then she pulls them in. Nonetheless it is a good technique to use while riding in sand since it works!

All that being said, the steering stabilizer is the best thing I added to the bike to improve handling in sand. After spending hours (if not a day or two) playing in the sand I would usually be pretty tired. Now it is a completely different story and I just enjoy riding that much better.

If you are new to riding then practice the techniques above and get a feel for riding in the stuff. The only other thing I would add is once the speed is up I get my weight as far back on the seat as I can and stand when I am entering turns. But if you are old and are at the point in life where you like to head out for a one or two week adventure a steering stabilizer will make that ride so much more enjoyable.
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2012 WR250R
2010 Beta 520 RR
2009 DL650
2001 GasGas XC250

02-06-2013, 05:46 AM   #32960
ggemelos

Joined: Sep 2004
Location: New York, NY
Oddometer: 137
Quote:
 Originally Posted by Llamaha Mind if I share my thoughts on this? Personally I have never needed a rear rack I just plonk whatever on the rear fender and strap it down. If you get the wolfman racks then you will have plenty of tie-down points. The radiator doesn't need protection any more than many other parts of the bike, you could just as easily dent a wheel on a rock and get stranded. My old skid plate created a horrible echo from the bottom of the bike... you may want to research this. (mine wasn't flatland though worth thinking about...) I have heard that the 4.7 doesn't get all of the fuel out of the wings, you may be getting the same amount of fuel from the safari but still have quite an agile motorcycle?
Thanks for all the feedback, I definitely eager to get people's opinion on how to best setup the bike. When traveling, I generally just strap down a waterproof duffel to the rear rack using rok straps. For normal every day use, I have a tail bag mounted on the rack. I guess you could to all of that without the rack, but it seemed easier.

As for the radiator guard, I have read that the larger tanks, Safari and IMS 4.7, are sufficient protection from a side impact and that an additional radiator guard is not needed. Is this a fair assessment, do a lot of people skip the radiator guard when running the larger tanks?
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 02-06-2013, 06:05 AM #32961 avgas amateur     Joined: Jan 2010 Location: Oregon Oddometer: 81 Thanks for sharing that video Joe, that's probably the coolest wr250r I've seen. __________________ 2012 Yamaha WR250R
02-06-2013, 06:17 AM   #32962
30Bones

Joined: Oct 2005
Location: Marion, IA
Oddometer: 4,636
Quote:
 Originally Posted by avgas Anyone out there not use a radiator guard and regret it? I'm considering one, but I'm cheap... err, I mean, I'm concerned about cooling.
BigDog doesn't, but he has the Safari tank to help protect it.

02-06-2013, 06:17 AM   #32963
Krabill

Joined: Oct 2005
Location: Tulsa, OK
Oddometer: 4,882
Quote:
 Originally Posted by avgas Anyone out there not use a radiator guard and regret it? I'm considering one, but I'm cheap... err, I mean, I'm concerned about cooling.
I don't use one and it's never been a problem, but then again, I don't fall down very often.
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02-06-2013, 07:04 AM   #32964
simmons1

Joined: Jan 2006
Location: Out Riding
Oddometer: 1,525
Quote:
 Originally Posted by Krabill I don't use one and it's never been a problem, but then again, I don't fall down very often.
Same here, plus my big tank gives some protection for minor tip overs.

If I was using the stock tank, or an IMS 3.1 I would have a radiator guard.
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Goldwing, Super Tenere, WR250R, ST1300, KLR, GS1000s, GT750, H2 750, H1 500

02-06-2013, 08:57 AM   #32965
UtahFox

Joined: Apr 2012
Location: Salt Lake City
Oddometer: 446
Quote:
 Originally Posted by Joe Watson Hey, Check out my vid of my WR250R before I sold it:
Love your build. I'd really like to setup the fairing like you have, but I have zero fabricating experience. I don't suppose you're going to sell the fairing and tower?

02-06-2013, 09:53 AM   #32966
jon_l

Joined: Feb 2008
Location: Collingwood, Ontario
Oddometer: 3,200
Quote:
 Originally Posted by jerrybiker Nice bike. I'm looking to get a new 2013. I rode a friend's 04 & it was sweet ride. I want to make a RR to AK.
There was no '04. You must have ridden the off-road WR250F. Not much similarity between WRF and WRR.
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02-06-2013, 10:50 AM   #32968
AKA Acorn27

Joined: Aug 2012
Location: S/E Wisconsin
Oddometer: 88
Quote:
 Originally Posted by cjbiker I just ordered the IMS 3.0 after agonizing about this since I bought the bike last November. For 99% of my riding, the 3.0 will be fine, but I hope to get back out west in the next couple of years, and I hope to do some big loops that will need 200+ mile fuel range. I chose the 3.0 because of the negative comments regarding fuel slosh and the added width, plus the extra fuel pump is a little too "Rube Goldberg" for my tastes. I'll add a Rotopax or a cheap 2 gal plastic tank on the back for epic rides.
Thanks for the feedback. I've been struggling with the 3.0 or larger? question for a while. Your post kind of helped me orgainze my thoughts, most likely the 3.0 would be my best option, and then carry more for the less frequent times I need more range.

02-06-2013, 11:01 AM   #32969
AKA Acorn27

Joined: Aug 2012
Location: S/E Wisconsin
Oddometer: 88
Quote:
 Originally Posted by yaw Hey 1-down 5 up. I've got 21,000 on my original 5/08 fuel pump. I'm sure others have more miles. I think they either go bad or they last and last and last...
Did a bit of searching, but this is the "MEGA" thread after all and it's tough to find specifics...

But anyway, is it others' experience that due to known failure issues, is an '08 fuel pump typically replaced by a dealer at no cost? Is there a service bulletin or warranty recall or anything for this issue? I'd rather address it before it fails. Maybe it never will fail, but if it does I can guarantee it won't be in my driveway....

02-06-2013, 11:54 AM   #32970
what broke now
Petroleum Brother

Joined: Jul 2011
Location: seattle
Oddometer: 1,394
Quote:
 Originally Posted by acorn27 Did a bit of searching, but this is the "MEGA" thread after all and it's tough to find specifics... But anyway, is it others' experience that due to known failure issues, is an '08 fuel pump typically replaced by a dealer at no cost? Is there a service bulletin or warranty recall or anything for this issue? I'd rather address it before it fails. Maybe it never will fail, but if it does I can guarantee it won't be in my driveway....
I have no idea about Yamaha's warranty policy, but I am convinced that the replacement pump offered by Yamaha is no better than the one in your bike; i.e., it may last a long time or give trouble soon.

I replaced the original in my 2008 thinking I would avoid problems and had it stall in warm weather on a tough uphill trail, but not since that event.
The pump I took out was sold to someone on here that has run it ~35000 or so miles without trouble. Mark Sampson [Big Dog] seems to be replacing his at 17k mile intervals, on his third now, I believe.

Cal Cycleworks sells one that I think is better that the Yam pump, but I am not certain of it's status lately. It requires some work to fit into the assy, not drop-in.

PS: most fi bikes using these small pumps also have occaisional failures, not just Yam.

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