My WR450 25 pound trim off...

You absolutely would be able to tell if you rode a bike 30 pounds lighter.

No, I can't. I couldn't tell the weight difference between my 2004 YZ450 and my 2006 WR450. It was about 30 lbs, but I only knew that because of the printed specs.

The 1 1/2 lbs savings was compared to the stock RM-Z seat. Like you said, it would be easy to make the carbon fiber base in your garage for under a $100. Still not worth it to me but here you go....  thinktechnology.us

The 1.5 pounds they quote is just for the foam !

http://thinktechnology.us/seatFoam.html

Edited by MidlifeCrisisGuy

The 1.5 pounds they quote is just for the foam !

http://thinktechnology.us/seatFoam.html

I didn't look at their website I got the info from the Dirt Rider magazine under their product test.

What are u using for a front # plate/shroud and which speedo eliminator?

Stefan Merriman put a YZ swing arm on his. Lighter unsprung weight matters more. It also improves cornering

What are u using for a front # plate/shroud and which speedo eliminator?

Just a standard YZ Acerbis number plate. I haven't eliminated the speedo sender yet, but I have some parts here to do it. I'll report back when I do.

Stefan Merriman put a YZ swing arm on his. Lighter unsprung weight matters more. It also improves cornering

There are 2 styles of modern YZ swing arms. The pre 2010+ YZ swing arms have a shaft that goes right through the swing arm. You can see it welded to the swing arm arms. The new style linkage bolts into the center of the new swing arm.

I was all set to do a swing arm swap until I found out it only saves about 1 pound. 15 ounces to be exact.

And its not a straight forward swap. The new YZ swing arm uses a 25mm axle. The 2011+ WR450Fs use a 22mm axle.

I have the Flatland Racing speedo eliminator but I like this one even more:  http://www.rainesracing.com/ProductDetails/tabid/74/ProductID/89/Default.aspx

 

I used a TI spring on my '09.  I believe it was a 5.5kg and the weight savings was about 1 lb but it was unsprung weight  which equates to 2 lbs above the spring.  Same goes for the swing arm.

I appreciate the effort you went through to write the thread on the WR trim down. I want to do most of what you did. Can you tell me what I need to do with the battery leads after removing the battery? Are there any tricks/tips on removing the starter gears and relays. Electrical is not my specialty.

I removed all the electrical from under the seat in one go. It should be fairly obvious what can go and what can stay. I removed the battery, the leads, all the relays and the rubber thingy they sat in. Its all plug and play.

The only thing you need to be aware of is that when you remove the black ground wire that goes from the battery to the engine case, it also serves as the ground connection from the stator. You need to replace that wire with a light weight wire going from one of the black wires that used to go to a relay to the frame or engine. If you dont do this, the fuel pump will cut out intermittently. Ask me how I know !

I did this in August and haven't looked at my bike for a couple months now. If you get stuck, I'll dig it out and take a few pictures.

As far as removing the starter, you need to plug the whole when you do. I used an automotive frost plug that pressed in with a small C clamp and minimal effort. The crankcase isn't pressured, so its more or less a splash guard. I made sure that the plug was a light fit, ie it could be removed and the starter bore wouldn't be messed up.

As far as removing the starter gears, just pull off the side cover and they will come right out.

As far as removing the starter clutch and drive gear, you need to remove the flywheel to do that. It takes a special tool. The part number is in the service manual. Other than that, its straight forward.

Edited by MidlifeCrisisGuy

I removed all the electrical from under the seat in one go. It should be fairly obvious what can go and what can stay. I removed the battery, the leads, all the relays and the rubber thingy they sat in. Its all plug and play.

The only thing you need to be aware of is that when you remove the black ground wire that goes from the battery to the engine case, it also serves as the ground connection from the stator. You need to replace that wire with a light weight wire going from one of the black wires that used to go to a relay to the frame or engine. If you dont do this, the fuel pump will cut out intermittently. Ask me how I know !

 

 

 

What should you do with the battery leads if you just want to remove the battery?

Edited by Navaho6

Midlife,

 

Have you looked at different tires?  I was changing out rubber last night and noticed that the oem Dunlops were significantly heavier than the new Pirelli XCMS tires I put on.   This is unsprung weight which is worth 2x the scale weight. 

What should you do with the battery leads if you just want to remove the battery?

Remove them. Replace the black one with a piece of 16 ga that goes from a black ground under the seat to the frame or engine. I went to the frame.

I'll just get the Shorai battery.  Only weighs 1.5 lbs.  The remaining weight associated with the gears and starter are really low and central to the bikes mass.  I want to focus on removing the unsprung weight and the weight that is not centrally located. Muffler, tires, and rear sprocket to start with.  One day, I may do the YZ swing arm. 

Edited by Navaho6

Any pics of this bike?

I'll just get the Shorai battery.  Only weighs 1.5 lbs.  The remaining weight associated with the gears and starter are really low and central to the bikes mass.  I want to focus on removing the unsprung weight and the weight that is not centrally located. Muffler, tires, and rear sprocket to start with.  One day, I may do the YZ swing arm.

The starter clutch and gear is spinning mass. Removing it really seems to increase the bike's agility.

BTW, all the talk about 1 pound of unsprung equalling 2 pounds of non unsprung weight isn't exactly true. And with something like a swing arm, most of the weight is low and toward the center of the bike. It doesn't weigh much back by the wheel, where most of the moevement occurs. This goes doubly for something like the rear shock.

Edited by MidlifeCrisisGuy

I thought about removing the starter etc but when I kicked it for the first time, I changed my mind.  The kick starter takes quite a bit more effort than I was expecting.  Plus, the '13 is taller than my '06 and I'm 5'-9".   Sure, there is some benefit of losing the starter and gears but there are times when having the e-start is really helpful. 

BTW, all the talk about 1 pound of unsprung equalling 2 pounds of non unsprung weight isn't exactly true. And with something like a swing arm, most of the weight is low and toward the center of the bike. It doesn't weigh much back by the wheel, where most of the moevement occurs. This goes doubly for something like the rear shock.

 

In the case of the swing arm, it's not 100% unsprung in the first place. The way the unsprung weight of the swing arm is derived is by first attaching the relay arm and the link bolt to it along with about a  3 pound weight hanging from the lower shock bolt to represent weight of the shock rod and half the rear spring.  Set the swing arm pivot on a rod supported by two jack stands and then weigh the rear end of the assembly while holding it level with the ground.  The weight shown on the scale is the unsprung portion, the rest is sprung weight.

 

Rear shocks mounted directly at an axle as they once were are "50/50" unsprung/sprung.  Mounted "upside down" as they commonly are now, such a configuration would simply be that the rod, piston, lower clevis, and half the spring's weight would be unsprung, with everything else sprung.  But when mounted 2/3 up toward the front as is current practice, you have to add the weight of the "unsprung" sections of the shock to the swing arm at the point where they attach to it.  With a scale set up as above, that puts roughly 2/3 the weight of those components on the sprung side of the equation, adding only a third of that weight to the axle end.  It's another advantage of such leveraged systems.

 

Unsprung weight interferes with suspension operation, which does have an effect on how the bike handles, but not so much with how light the bike feels.

Just swapped out the muffler for a GYTR FMF with quiet core insert. Exactly 2 lbs savings.

Im new here to TT and was just reading through these forums and came across this one and had to ask I have a 2014 wr450 and have put every protective things I can works skid,sharkfin,caliper guard and radiator braces so I know it's heavy but all my riding buddies are all on cr250 and yz250 nice and light all have been riding 10+ yrs and the WR eats them up 78 through 3 ft whoops to hill climbs the only reason for me wanting to ride a lighter bike it when I go to ocotillo for some time in the air so if your jumping I understand needing a light bike but on a WR why

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