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Discussion Starter · #1 ·
I just (yesterday) bought my Z125 Pro with one of my specific plans being to reduce its already low weight even more, as much as practical!

I'm putting together a plan that I will execute during the winter, but need to know the actual (not estimated) weights of the following individual components or assemblies:


OEM IRC NR77U tire – front

OEM IRC NR77U tire – rear

Entire OEM exhaust system (from cylinder head to tip of exhaust)

OEM battery: FB Siam Furukawa FTH4L-BS 12 Volt, 3 AH
Also dimensions of battery (L x w x H)

OEM Intake system, from airbox to “in” end of the throttle body

OEM Rear upper fender assembly (NOT the fender that follows the tire radius), including license plate holder and signal lights, but not license plate light and not license plate itself

OEM Passenger pegs, including all pieces that mount them, that can be removed without anything else other than passenger pegs being affected (On some bikes, the same mounting parts can be required to hold things like the exhaust, or rear master brake cylinder, so cannot be removed)

OEM undercowl (under the engine, that hides the exhaust header)

OEM front fender

OEM lower rear fender (the one that follows the radius of the rear tire)

OEM handlebar assembly including bar, bar mount, clutch lever & mount, front brake lever (but NOT the master cylinder and mount because they don’t get replaced), but not grips and throttle assembly (because they too do not get replaced)

OEM front brake disk without its mounting bolts

OEM rear brake disk without its mounting bolts

OEM front wheel assembly, with or without its tire and brake disk

OEM rear wheel assembly with or without its tire and brake disk

OEM rear sprocket

OEM front sprocket

OEM seat

OEM pair of front signals

OEM mirrors (left and right added together)

OEM footpegs and all their related parts that could all be replaced by aftermarket rearsets

OEM chain guard (but not including its mounting hardware)

OEM rear shock absorber

I know some of you have had one or more (maybe even ALL?) of these components or assemblies off of your Z125 at one time or another, when doing maintenance, replacement, or repairs - especially those of you who race your Z125.

If you have access to a reasonably accurate scale (e.g. postal scale, kitchen scale, but NOT a bathroom scale) with a weighing range that is appropriate for the components being weighed (e.g. a scale that is designed to handle items that weigh anywhere from a fraction of one pound to maybe 20 or 30 lb), it would be really helpful if you could get me some of these weights - even 1 or 2 would be helpful.

I plan to build a worksheet in Excel, like I did for my recent Yamaha R3 weight reduction project. For the Yamaha, that worksheet to-date has documented how to take 44 lb off of that bike! It utterly transformed the performance of that bike!

If we can hit just a third or half of that 44 lb, we would be making a huge difference in the performance of the Z125, especially if many of the weight reductions come off of rotating parts (e.g. sprocket, wheels, tires, brake rotors, primary gear (I already have the weight of the OEM primary gear).

I will publish that worksheet at frequent intervals as the project develops, so that you can use some of the ideas on your own bikes.

If any of you can help, it would be greatly appreciated.

Jim G
 

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I have my passenger pegs off, replaced with sliders. I also have a stock rear shock that I need to open and see about modifying for service. I also have a set of stock rearsets somewhere. Not sure when I will be able to try and weight all this though. Also have a stock handlebar.

Mirrors come right off so shouldn't be that hard to weigh.
 

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RE: Passenger pegs. You can save some weight from chopping the passenger peg arms off. Just don't do it before you find out you needed something to mount your new muffler to.
 

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Discussion Starter · #4 ·
RE: Passenger pegs. You can save some weight from chopping the passenger peg arms off. Just don't do it before you find out you needed something to mount your new muffler to.
Yes, I try to avoid making "irreversible" deletions! Especially, since my track record is to eventually sell any motorcycle that I modify and enjoy for a while, as I always need a new "project"!

Jim G
 

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Discussion Starter · #5 ·
I have my passenger pegs off, replaced with sliders. I also have a stock rear shock that I need to open and see about modifying for service. I also have a set of stock rearsets somewhere. Not sure when I will be able to try and weight all this though. Also have a stock handlebar.

Mirrors come right off so shouldn't be that hard to weigh.
If you can find the time to do the weighing, it would be a great help, and will start to build a forum information resource on component weight reduction potential.

Jim G
 

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Discussion Starter · #7 ·
You might find a few suggestions here :rolleyes:
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https://www.z125owners.com/forum/appearance-modifications/5481-light-right.html
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I Haven't seen if your going inside motor yet , but the lightened primary is like 2lbs lighter I think and still rated as the bang for your buck for better performance . But i don't have one myself ?
I had not yet found that thread, so thank-you! I'll read through it!

Yes, I do plan to do the primary gear mod - I had indeed seen a vendor ad that highlighted the relatively huge drop in weight in going with the lightweight version. I had done a lighter flywheel on a Ducati Monster 916cc bike many years ago and recall how dramatic a difference it made not only in bike weight, but also in throttle response, because it is a rotating component, and it rotates at an rpm way beyond what the wheels, tires, sprocket, and brake rotors do, so its moment of inertia is dramatically decreased by such a big weight reduction.

Jim G
 

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Discussion Starter · #8 ·
Wow, just looked through that older thread. THAT was a blast! Leandro was SERIOUS. And, I did get a couple more ideas from it. The aluminum swingarm was over the top. I had no idea anyone made one.

Jim G
 

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I did the absolute easiest item on your list! ;]

OEM Seat: 2.25 kg ±0.05 kg (includes tool kit)

Toolkit: 0.30 kg ±0.05 kg

Time to buy some titanium tools.
 

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Discussion Starter · #10 ·
I did the absolute easiest item on your list! ;]

OEM Seat: 2.25 kg ±0.05 kg (includes tool kit)

Toolkit: 0.30 kg ±0.05 kg

Time to buy some titanium tools.
Thanks, Ando! That's two items done off the list! A big project is built one small piece at a time. It was stuff like this, repeated multiple times, that eventually got me that 44 lb weight reduction on the Yamaha. What a ride that bike is now - my absolute favorite of all 44 bikes I have owned.

Jim G
 

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I'm already annoyed with the ±.05kg... We have one other counting scale lying around (that we use for actual part counting) that might be large enough to balance the seat on. Lemme go see.
 

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Discussion Starter · #12 ·
I'm already annoyed with the ±.05kg... We have one other counting scale lying around (that we use for actual part counting) that might be large enough to balance the seat on. Lemme go see.
That's the spirit! + or - .05kg = = or - 0.11 lb after all!! Seriously, I round all the weights to the nearest 0.1 lb for display in the worksheet, although I do carry the 2nd decimal in Excel for calculations.

Right now, the Yamaha is sitting at a frustrating 300.7 lb, and I need a good mod to get me a biut more than that 0.7 lb so I can be "under 300 lb"!

I think I will get 0.17lb of that by taking the swingarm spools off, because using my Pitbull FORWARD HANDLE rearstand is hard when using the spools because I cannot SEE the righthand side spool when lifting the pitbull into engagement position (carbon fiber muffler gets in the way). I think the non-spooled Pitbull adaptors that engage the swingarm directly will work a lot easier, so a 2-way win.

But that still leaves me 0.53 lb above 300. :(

Jim G
 

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Right now, the Yamaha is sitting at a frustrating 300.7 lb, and I need a good mod to get me a bit more than that 0.7 lb so I can be "under 300 lb"!
I vote you skip lunch and claim you made it!

That is annoyingly close. Let us know if you find those extra couple of ounces.
 
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