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Discussion Starter #1
Great little piece of kit. ~2 lbs less than stock.

I didn't like the noise it made but I loved the way it rode. Ultimately my desire to not sound like a supercharger on wheels got the best of me. I've poked and prodded the manufacturer, seller, and reseller and all claim the noise is perfectly normal despite "silent OEM-like operation" being listed as a feature. ¯\_(ツ)_/¯

Anyway...

$45 takes it, shipped in the Lower 48 states, sorry Canada!

Paypal F&F or you pay the fee. PM me if you want it shipped elsewhere and we can work something out.
 

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Great little piece of kit. ~2 lbs less than stock.

I didn't like the noise it made but I loved the way it rode. Ultimately my desire to not sound like a supercharger on wheels got the best of me.
Sorry it didn’t work out for you. As you note, it’s worth doing if there are no issues. I seem to remember an earlier post about gear noise that some folks experienced. In my case I experienced zero issues installing and with noise after. And this was before I went away from the stock air box and exhaust. I certainly would have heard any noises then. Did I just get lucky?

JW
 

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Did I just get lucky?
As far as I can tell, yeah. Sounds like most people get the whine for the first 20-80 miles. After that initial break in period the noise is still present, but significantly lower volume.

There are threads on the forum documenting this same noise on completely stock bikes and it was resolved by replacing the primary or secondary gears. So there is some sort of variation in manufacturing (this isn't a top dollar bike folks) and I just happened to get a goofy pairing that didn't work well together. I'm still considering buying another and crossing my fingers.

I so desperately wanted to be OK with it. At half the volume I would have thought the whine was pretty cool, people might stop you at fuel ups and ask if your bike has a blower, as it was I was just getting dirty looks. Whoever buys this may find that it is silent in their bike. Like any purchase and installation of aftermarket parts, YMMV.
 

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Discussion Starter #5
Agreed. I would very much like to lighten my OEM primary. It would end up costing more than the T bolt replacement, but at least I know it would run smooth.It was mentioned that it may be through hardened and not just case hardened so I'm not sure how much of a PITA it would be to turn down.

I assume you cannot run it due to classing?
 

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Yes, the engine must be stock internals, and unmodified.

I'm certain that there are a few tools that would eat it right up, even if it was hardened. I'd start with a saw and lop off most of the ring, probably get 2/3 of the weight gone in this rather crude fashion. If you really wanted a workout, you could chuck it in a drill, and take a grinder and go at the rest of the weight after a saw cut. Never discount brute force and ignorance to get a job done!

Another really crude way would be to take a drill bit and start drilling holes. Drills can remove a huge amount of material fast when you use them right. I bet you could remove half the weight with drills through from front to back, or through the circumference (take your pick)

And I'd take a file to that mass and see what happens, doesn't make sense to harden the whole thing. I would guess induction hardening of the gear teeth is all that was done.
 

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Discussion Starter #7
Another really crude way would be to take a drill bit and start drilling holes. Drills can remove a huge amount of material fast when you use them right. I bet you could remove half the weight with drills through from front to back, or through the circumference (take your pick)
Oooh, I like this idea. We have a crude mill and rotary table at work. Might have to come in on some weekend and make chips.
 

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I'd cut a stock one down. If I could run it, I'd buy it from you. Then again, can't even ride any of my bikes right now (still).
You mean like this? I have a couple more left from the first run I machined. How much is it worth? I didn't plan on doing any more than for my riding buddies, but if you want one... And I'll need your heavy stock gear sent back as a core.

But they are silent.
 

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Discussion Starter #10
You sir, have my attention. Looks great!

Wonderful... go online to try to recover some sunk cost... end up spending more money on the same mod... That's gonna be a hard sell with the wifecountant. I will let you know, thanks for chiming in!

ʕʘ‿ʘʔ
 

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That hex on the end is a very good idea!

Was it hardened or not?
Yeah, I thought it needed a better way to torque down the 19mm nuts. Just get a 26mm wrench and you're set.

Not very hard when compared to a carbide endmill. It doesn't take long to cut, but making the fixture, programming the CNC and the setup time all add up. I wasn't planning on selling any, just making them for myself & a few friends. But maybe now I have a few more friends...
 

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You would need to figure in the cost of the endmill and your time, really need enough on hand to make a batch run of them to make your time better.

You could make a two piece hex block for a manual mill, but I'd probably just set it up with some angle blocks and cut. I'd probably be lazy and just cut opposing flats, or maybe a square. And on my little mill I'd still be using a cutting disk to remove the bulk.
 

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After reading about the whining and the stalling from a dead start I am glad I didn’t install my TB lightened one yet. I am going to weigh it and weigh my stock one and remove half the weight between the two. I’m thinking no whine and a slight performance increase and still retain a bit of flywheel effect for starts from red lights.any one else think about this ?
 

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After reading about the whining and the stalling from a dead start I am glad I didn’t install my TB lightened one yet. I am going to weigh it and weigh my stock one and remove half the weight between the two. I’m thinking no whine and a slight performance increase and still retain a bit of flywheel effect for starts from red lights.any one else think about this ?
I dont think using a stock one cut down to the aftermarket size ones would whine..(i dont think it's the size creating the whine) . but it would not avoid the stalling that you mention if thats happening.
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I'd cut from the inside of the mass ring out. You could probably remove 3/4 of the static weight while retaining 1/2 of the rotating inertia.

The other thing you could do is drill large holes through the ring, harder to take off large amounts of mass, but an easier process for most people.

Make sure to balance this shaft after doing this work! Get a large RC propeller balancer to do this, should be sensitive enough to get it back in balance.
 

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Discussion Starter #17
Hey jaydollar. Welcome to the forum.

Stalling is a completely different issue. There was a recall on the 2016/2017 ECUs to raise the idle speed. You are correct that dropping rotating mass off of the crankshaft will require you to change your habits to give the bike a little more throttle to get off the line, but nothing you can't re-learn in an afternoon.

Stalling because of the light "flywheel" is user error, plain and simple. I think the lighter primary with the stock clutch would be annoying and vague, probably more prone to stalling in inexperienced hands. I highly recommend grabbing an HD clutch kit to install as long as you have the bike apart.

RE: Noise

Check out the video in the first post of THIS thread. That's the noise that most people are getting from their lightened primary, if any. I was unlucky and the teeth didn't seem to mesh well with my specific secondary gear (clutch basket) so it sounded like that bike at idle and was hilariously loud under load. But you are correct, trimming weight from your OEM primary will retain the same noise level.

One last thing. You mention "increased performance". This isn't a power part. The power delivery feels different, the engine blips revs faster and smoother, there is less engine braking, but it's the same 8HP you have now.

If you already have the part, I say install it and try it out first hand. An hour of your time and $12 of gaskets is all you stand to lose.
 

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I have a tb lightened primary. Last oil change I added some motorkote and the noise was reduced significantly. I ride with two other z125pro and they noticed as well.
 

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I'm probably going to switch to 20/50 oil next time I can run it, should help keep the heat away. Why I say this:

When I put the big bore kit on my Buell, I used break in oil for the first few hundred miles, then went to Mobile1 motorcycle 10/40. Things were getting hot. Switched back to the preferred Mobile1 V-Twin 20/50 and it was back to normal cool operating temperatures.

So since these little guys work so hard, I think I'm going to go with the V-Twin 20/50 next time and see if it helps keep things a little more cool.
 
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