YZ125 engine characteristics

Froggy76
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Froggy76
Edited Date/Time 1/12/2019 1:55pm
Hi all,

Since I can t test drive a YZ125 prior to buying one, I d like to know what m in for.
Is the YZ125 motor really snappy or is there a real powerband that comes on abruptly.
I tried a TC125 and it was awesome and really not nasty power band, fairly controlled. Can I expect the same from the yz 125 or is there a real difference.
If the YZ125 is aggressive van you tame I by either a smaller rear sprocket?
Truth is, I d love to get a TC125 but here in Australia, there s some real good deals on the yz and the price difference between the two is in excess of $2400.
M 42, and intend to race for fun next year. The yz comes fitted with gytr silencer, pipe, Reed valves and rear sprocket at no extra cost.
Parts are usually cheaper too on the Yamaha in Australia.
Hope to hear from you...
2
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fanger
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fanger 11/20/2018 4:14am
11/20/2018 4:14am
There’s a shop in Melbourne selling 2019 yz 125’s for 8k from memory, you’d be mad not to get one.
mxrose3
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mxrose3 11/20/2018 7:11am
11/20/2018 7:11am
The YZ125 engine, is a pretty quick-revving but easy to ride engine. I don't think it is quite as powerful as the TC or KTM 125, but it is competitive.
Find one to try out and then you can make your decision.

2stroked
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2stroked 11/20/2018 8:10am
11/20/2018 8:10am
The TC125's Ive had the opportunity to ride and race were gutless pigs. Dont care what all you ktm/husky fan boys say. Try to explain it away but they're pigs. By the time they get up on the pipe its too late, and flat.

The KTM125 feels better down low, has a midrange, and a great top end. It really pulls hard up top.

The YZ125 has remained basically unchanged for over a decade for a reason. It works. It does EVERYTHING well. There isnt anything that is exceptional on the bike besides the KYB SSS suspension and the yamaha quality/durability. The motor is very easy to ride in my opinion, and covers all the bases power wise. It has good low end (for a 125), a meaty midrange, and the top end pulls and pulls. Its not quite as powerful overall as the KTM. However I feel personally its easier to ride the YZ fast opposed to the KTM as a total package. The YZ has a broader powerband, and the KTM is more centered on the upper midrange to top end. (its built for fast guys to go fast)

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yz133rider
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yz133rider 11/20/2018 9:02am
11/20/2018 9:02am
2stroked wrote:
The TC125's Ive had the opportunity to ride and race were gutless pigs. Dont care what all you ktm/husky fan boys say. Try to explain it...
The TC125's Ive had the opportunity to ride and race were gutless pigs. Dont care what all you ktm/husky fan boys say. Try to explain it away but they're pigs. By the time they get up on the pipe its too late, and flat.

The KTM125 feels better down low, has a midrange, and a great top end. It really pulls hard up top.

The YZ125 has remained basically unchanged for over a decade for a reason. It works. It does EVERYTHING well. There isnt anything that is exceptional on the bike besides the KYB SSS suspension and the yamaha quality/durability. The motor is very easy to ride in my opinion, and covers all the bases power wise. It has good low end (for a 125), a meaty midrange, and the top end pulls and pulls. Its not quite as powerful overall as the KTM. However I feel personally its easier to ride the YZ fast opposed to the KTM as a total package. The YZ has a broader powerband, and the KTM is more centered on the upper midrange to top end. (its built for fast guys to go fast)

Lol
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The Shop

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Moto520
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Moto520 11/20/2018 9:19am
11/20/2018 9:19am
mid and up on the YZ125. Good power for a 125
kb228
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kb228 11/20/2018 9:57am
11/20/2018 9:57am
Try it. If its too much you can tune the ignition timing or add a flywheel weight to smooth it out. The yz is cheaper and honestly if youre worried about power on a 125 you should focus on saving money. Having the best bike isnt going to help you. Save cash and get it set up so youre comfy
Jrewing
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Jrewing 11/20/2018 1:49pm
11/20/2018 1:49pm
2stroked wrote:
The TC125's Ive had the opportunity to ride and race were gutless pigs. Dont care what all you ktm/husky fan boys say. Try to explain it...
The TC125's Ive had the opportunity to ride and race were gutless pigs. Dont care what all you ktm/husky fan boys say. Try to explain it away but they're pigs. By the time they get up on the pipe its too late, and flat.

The KTM125 feels better down low, has a midrange, and a great top end. It really pulls hard up top.

The YZ125 has remained basically unchanged for over a decade for a reason. It works. It does EVERYTHING well. There isnt anything that is exceptional on the bike besides the KYB SSS suspension and the yamaha quality/durability. The motor is very easy to ride in my opinion, and covers all the bases power wise. It has good low end (for a 125), a meaty midrange, and the top end pulls and pulls. Its not quite as powerful overall as the KTM. However I feel personally its easier to ride the YZ fast opposed to the KTM as a total package. The YZ has a broader powerband, and the KTM is more centered on the upper midrange to top end. (its built for fast guys to go fast)

Fuck low end in a 125. You use it once or twice on a track and usually by mistake!!

You sound like 4stroked champ. Mid and up for my 1dingers is what I care about
mark_swart
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mark_swart 11/20/2018 1:58pm
11/20/2018 1:58pm
Does "gives you a big ass grin" count as an engine characteristic?

For a 125, it's extremely usable and broad, pulling from mid range through solid top end. It does have a mid range hit, but it isn't sketchy or hard to control/predict.

I've never ridden the TC 125. I'm a +40 intermediate and raced a YZ125 last year and did well. This year I was on a 250F and the guy I battled the whole season was on a YZ125.

My favorite thing about the YZ 125 is that I could do extremely long motos on it without getting tired. That's a big plus for those of us that aren't able to train all that much.
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chump6784
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chump6784 11/21/2018 3:09am
11/21/2018 3:09am Edited Date/Time 11/21/2018 3:09am
Coming from a yz250 the yz125 feels as if there is no hit. Truth is, there is not much bottom and as it pulls into the mid there is a surge that continues on to the top. It only hits as hard as your right wrist lets it. My wife learned to ride on a 125 without any drama's

Here is a dyno graph with a yz 125 comparing the stock pipe and hgs pipe and muffler. I just picked up a yz250 that came with a HGS and compared to the stock pipe it rips

ledger
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ledger 11/21/2018 11:40am
11/21/2018 11:40am
I cleaned up the ports on my old 05 YZ 125 and gained a bit of over rev. I was stupid to sell it cause it was so much fun.
GeorgiePorgie 11/21/2018 12:42pm
11/21/2018 12:42pm
Your most rewarding gains on a 125 is when she’s screaming. If you can’t keep her at the peak of the rpm range then maybe get a 250.

But....still think you should get the 125 and just scream it.
Froggy76
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Froggy76 11/21/2018 1:11pm
11/21/2018 1:11pm
Hi guys,

Thanks for all the info and replies.
Very interesting. I actually email the Yamaha dealer to get ball rolling. Can t wait.

Finger: you r spot on, some really good deals on the YZ125 at the moment. Considering it comes with a gytr muffler, pipe, reeds and sprockets, it s great.

Chump, thanks for the graph, quite interesting.

Goergie, you are also spot on. I have 250crf250 2015 and though it s good, easy to ride, I feel bored on it and lack fun. Not saying it s a bad bike as I m sure I don t exploit it to it s full potential but I just got the feeling it s the same thing over and over.
When I borrowed a TC125, even though I was probably as slow as a turtle, I had a smile on. Felt li,e I was going 100miles per hour with that screaming engine. Hoping the yz will do the same for me

I ll be racing that YZ125 in the senior novice next year. More for fun than anything else, but I ll give it a good shot at winning ?
Racerxx
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Racerxx 11/21/2018 2:18pm
11/21/2018 2:18pm
The one thing you'll hear from anyone who owned a YZ125 is "I wish I never sold it" enjoy, they are so much fun to ride. What reed does the bike come with? I liked the V-Force 4 and an FMF fatty pipe and cleaning up the ports makes a difference also.
2
Caseclosed713 11/21/2018 2:46pm
11/21/2018 2:46pm
I had a 2013 YZ125 and wish I never sold it. I like my YZ250, but I loved the 125. I might go back next year...
Richard Tease II 11/21/2018 3:06pm
11/21/2018 3:06pm
Froggy76 wrote:
Hi all, Since I can t test drive a YZ125 prior to buying one, I d like to know what m in for. Is the YZ125...
Hi all,

Since I can t test drive a YZ125 prior to buying one, I d like to know what m in for.
Is the YZ125 motor really snappy or is there a real powerband that comes on abruptly.
I tried a TC125 and it was awesome and really not nasty power band, fairly controlled. Can I expect the same from the yz 125 or is there a real difference.
If the YZ125 is aggressive van you tame I by either a smaller rear sprocket?
Truth is, I d love to get a TC125 but here in Australia, there s some real good deals on the yz and the price difference between the two is in excess of $2400.
M 42, and intend to race for fun next year. The yz comes fitted with gytr silencer, pipe, Reed valves and rear sprocket at no extra cost.
Parts are usually cheaper too on the Yamaha in Australia.
Hope to hear from you...
Are you a Melbourne lad?
If you get the YZ and are in Melbourne speak to SPMX1 (Steve Powell) he has done extensive testing with Cam Taylor on the 125
Froggy76
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Froggy76 11/25/2018 11:40pm
11/25/2018 11:40pm
M in Brisbane mate.
Crap, no more 18 yz 125 available for such a good price.
Dealer being a ktm and Yamaha, told me I could have a 18 125 six for $9000. $500 more than the 18 yz. Might be worth.

New question: how s the 125sx??

Easy to ride? Air fork?
Jrewing
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Jrewing 11/26/2018 2:57am
11/26/2018 2:57am Edited Date/Time 11/26/2018 2:59am
Froggy76 wrote:
M in Brisbane mate. Crap, no more 18 yz 125 available for such a good price. Dealer being a ktm and Yamaha, told me I could...
M in Brisbane mate.
Crap, no more 18 yz 125 available for such a good price.
Dealer being a ktm and Yamaha, told me I could have a 18 125 six for $9000. $500 more than the 18 yz. Might be worth.

New question: how s the 125sx??

Easy to ride? Air fork?
More bottom mid and top. Air fork works good.
Revs to the moon and back. Yes easy to ride. Try to blow it up and you’re riding it correct. Ask the shop for the jetting specs they use.

Pit Row

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Mx451
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Mx451 12/5/2018 7:54pm
12/5/2018 7:54pm
So what did you get?
Froggy76
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Froggy76 12/6/2018 2:37am
12/6/2018 2:37am
Nothing. Missed out on all great 18 deals. There s a few interstate but by the time you pay the freight it s not worth it.

I literally walked in to get a 125sx 2018 and the guy was wheeling it out strainght onto his trailer.

Next best option was a TC125 but there weren’t much on special at $10000, $500 off the retail.

I ll just have to pounce on the 19 when they r on special
Mx451
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Mx451 12/6/2018 7:23am
12/6/2018 7:23am
That sucks. So are you bikeless until that happens? I'm interested in your plight because I'm about to pull the trigger on a new yz125.
Froggy76
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Froggy76 12/6/2018 12:52pm
12/6/2018 12:52pm
No no, I still have my trusted 2015 Honda CRF250R. This thing is pretty good but I just wanted a new bike. I feel for me there was no point buying a 450 and wanted something light/nimble.

Not sure about you or the USA, but bikes are pretty expensive here in Australia.
A new 125sx is about $11000 and they drop to $9000 if you wait 8 months. The yz are cheaper by $1000 and drop to $8000 when they want to start getting rid of stock.

I would not say I am short of money, but for me a saving of $2000 if not more is not negligible to have to wait 8 months. I probable won t have to wait that long to be honest. The 19 should start being on sale very soon I believe.

Could always buy second hand but I usually don t buy second hand. I m a bit weird like that ?
BikeGuy321
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BikeGuy321 12/6/2018 2:03pm
12/6/2018 2:03pm
If you were even somewhat considering a 450, I'd say you would probably like a 250 smoker more than a 125. They're not nearly as difficult to ride as people make them out to be. Once you're riding tracks with bigger jumps, 125's aren't all that fun in my opinion because you almost always have to rail the outside line and hope you keep enough momentum to clear the jump. On 250's you can use a lot more inside lines and actually take advantage of the bike's handling ability.
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mattyhamz2
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mattyhamz2 12/6/2018 2:58pm
12/6/2018 2:58pm
Racerxx wrote:
The one thing you'll hear from anyone who owned a YZ125 is "I wish I never sold it" enjoy, they are so much fun to ride...
The one thing you'll hear from anyone who owned a YZ125 is "I wish I never sold it" enjoy, they are so much fun to ride. What reed does the bike come with? I liked the V-Force 4 and an FMF fatty pipe and cleaning up the ports makes a difference also.
This is so true. Had an 03 yz125 back in 2010 and completely rebuilt it. Rode it 2 times and sold it to pay my dad back for lending me money to buy a new truck. Regret it to this day.
mattyhamz2
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mattyhamz2 12/6/2018 3:02pm
12/6/2018 3:02pm
Froggy76 wrote:
No no, I still have my trusted 2015 Honda CRF250R. This thing is pretty good but I just wanted a new bike. I feel for me...
No no, I still have my trusted 2015 Honda CRF250R. This thing is pretty good but I just wanted a new bike. I feel for me there was no point buying a 450 and wanted something light/nimble.

Not sure about you or the USA, but bikes are pretty expensive here in Australia.
A new 125sx is about $11000 and they drop to $9000 if you wait 8 months. The yz are cheaper by $1000 and drop to $8000 when they want to start getting rid of stock.

I would not say I am short of money, but for me a saving of $2000 if not more is not negligible to have to wait 8 months. I probable won t have to wait that long to be honest. The 19 should start being on sale very soon I believe.

Could always buy second hand but I usually don t buy second hand. I m a bit weird like that ?
I know that used yz's are probably still expensive for you Aussies, but if you can get a good one for a decent price I wouldn't hesitate to go used. You can save money vs new and get things like suspension and motor freshened up.
Dick Trickle 12/6/2018 3:18pm
12/6/2018 3:18pm
As im a 54 year old vet, lugging around a heavy bike is not an option anymore.
I decided to pull the pin on a 2019 YZ125. A few reasons. That mob in Melbourne has them going out the door for $7990 ($5700 USD). Thats a pretty good price.. so i grabbed one, and they are shipping it to my area still in the crate.

I want a brand new bike so i know the history. I also want a brand new bike so i dont have to replace any bearings, pistons etc and have any worn out parts. I used to beat the hell out of my 125's when i was a kid and at the end of the season they were just about ready for the scrap yard.

I am a Yamaha man, but i went for the YZ because of the reviews, SSS suspension, quality and reliability. I dont need 2 extra horsepower, but i do need great suspension, light weight and reliability. Also, the model has not changed in umpteen years, so there is a ton of cheap parts available.

This will be my last bike. I want to enjoy the last few years, so i want a light weight fun bike!! My boy is on a YZ85, so the 125 will probably been handed over to him in a few years.




Cheers... Braaaaap......
1
Mx451
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Mx451 12/7/2018 11:17am
12/7/2018 11:17am
Dick Trickle wrote:
As im a 54 year old vet, lugging around a heavy bike is not an option anymore. I decided to pull the pin on a 2019...
As im a 54 year old vet, lugging around a heavy bike is not an option anymore.
I decided to pull the pin on a 2019 YZ125. A few reasons. That mob in Melbourne has them going out the door for $7990 ($5700 USD). Thats a pretty good price.. so i grabbed one, and they are shipping it to my area still in the crate.

I want a brand new bike so i know the history. I also want a brand new bike so i dont have to replace any bearings, pistons etc and have any worn out parts. I used to beat the hell out of my 125's when i was a kid and at the end of the season they were just about ready for the scrap yard.

I am a Yamaha man, but i went for the YZ because of the reviews, SSS suspension, quality and reliability. I dont need 2 extra horsepower, but i do need great suspension, light weight and reliability. Also, the model has not changed in umpteen years, so there is a ton of cheap parts available.

This will be my last bike. I want to enjoy the last few years, so i want a light weight fun bike!! My boy is on a YZ85, so the 125 will probably been handed over to him in a few years.




Cheers... Braaaaap......
Sounds reasonable to me. I'm 40 and have some rotator cuff issues so I too want a smaller, lighter bike to ride/race. I'm a mid pack A vet so who gives a shit if going to a 125 means the difference between 4th and 6th for example. Also they are super fun to ride.
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