OzVMX Forum

Marque Remarks => Yamaha => Topic started by: Rossvickicampbell on January 01, 2009, 02:19:48 pm

Title: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 01, 2009, 02:19:48 pm
Am I missing something here or has this guy got it all wrong - lists as a 125B "last of the twin shocks" - shouldn't that be an A?

http://cgi.ebay.com/ebaymotors/Motorcycles___1975-125-B_W0QQitemZ200291514034QQddnZMotorcyclesQQddiZ2283QQcmdZViewItemQQptZUS_motorcycles?hash=item200291514034&_trksid=p4506.c0.m245&_trkparms=72%3A727%7C65%3A12%7C39%3A1%7C240%3A1318

cheers

Rossco
Title: Re: 1975 Yamaha YZ125b
Post by: brent j on January 01, 2009, 02:59:43 pm
According to my listing the 453 model code is a YZ125A

Maybe it was sold in 75 but it's a 74 model.
Title: Re: 1975 Yamaha YZ125b
Post by: albrid-3 on January 01, 2009, 04:09:45 pm
All yamaha 1973 to 1974 model  yz came to Australia first before Amercia got them, they recieved them  a year later 1974 to 1975.
cheers
dav
Title: Re: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 01, 2009, 04:27:17 pm
thats correct Dav but the 125 B was first of the monoshocks not a twin shock - yes?
Title: Re: 1975 Yamaha YZ125b
Post by: brent j on January 01, 2009, 05:26:07 pm
From memory there was no YZ125B, they went from the "A" in 74 to the "C" in 75 but all other Yamaha's had the "B" model designation in 75.
That's why in 76 they came out with the YZ125X, when all others were up to "C". That put the letters right for the following "D" models.

Where's Nathan ???

Brent
Title: Re: 1975 Yamaha YZ125b
Post by: JC on January 01, 2009, 05:28:20 pm
Thats how I understand it too Brent. Never was a YZ125B
Title: Re: 1975 Yamaha YZ125b
Post by: firko on January 01, 2009, 05:45:49 pm
It seems that the YZ125B is a model
year  cap  model     engine nos    quantity produced
1974 125 YZ125A   453-000101     7730
1975 125 YZ125B   453-100101     101620
I downloaded the above from Yamahas site and the below from http://www.austmcycleadventures.com/yamaha/yzseries74.htm (http://www.austmcycleadventures.com/yamaha/yzseries74.htm) Note the different frame/engine#prefix from both sources. the bike for sale with engine #453-101153 fits right in with the above.
YZ 125A 1974     frame and engine prefix 453 453 
YZ125B  1975     frame and engine prefix 492 492 ????
Title: Re: 1975 Yamaha YZ125b
Post by: LWC82PE on January 01, 2009, 06:40:19 pm
how do you find out production numbers of these old bikes?
Title: Re: 1975 Yamaha YZ125b
Post by: Tim754 on January 01, 2009, 06:48:25 pm
Almost impossible L ,just add up the frame numbers for a rough estimate is about the only way.
Title: Re: 1975 Yamaha YZ125b
Post by: Nathan S on January 01, 2009, 07:07:06 pm
YZ125B is a yellow 125A. Not sold in many markets, possibly only the USA.

The YZ125C was the first 125 monoshock, but it really 'should' have been the YZ125B, blah blah (has been discussed several times before, a search will reveal whatI'm too lazy to type).
Title: Re: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 01, 2009, 07:43:09 pm
well there you go - never knew there was such a beast - thought it looked like an A

cheers and thanks

Rossco
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 03, 2009, 10:56:06 am
I just found one of these in Silver, was hoping it was a 250 , but turned out to be a 125. guy sold it to me was convienced it was aD Dt , even after i said it was a YZ with the stap on the tank, ah well if he says its a Dt for sure who am i to argue.   Was prity excited there for a while as he was discribing it i was creaming my jeans as it sounded like a 250.  Ahh well there is always next time i guess.    You looking to buy one Ross ?

also looking at the motor  id say they look more like a MX or DT engine, maybe the 125 was a bastard just to fill a segment in the line up it till the japs got sorted  ??? they dont look very Race bred to me, he guy also told me back in the day it had mods like the 250 forks and somthing about the gear sets changed to somthing better, which again makes me think they were'nt so flash off the showroom floor
Title: Re: 1975 Yamaha YZ125b
Post by: Nathan S on January 03, 2009, 11:25:03 am
What's the prefix?

The YZ125A is a tricked up MX125A. Main differences between the two are the YZ's alloy tank, closer ratio gearbox, no auto-lube, different barrel, and electronic ignition.

I don't know of a 'better' gearbox for them, unless you slap in a whole 125C bottom end. The 250 forks are definitely a huge step foward - 34mm (rather than 30), and more travel.

As a race bike, they're miles behind the Elsinore and the KX. But they're a good honest little bike. Given a few mods, they can have the best motor in the class, and handling that's perfectly acceptable, but the 5-speed box will be a hassle on most tracks.
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 03, 2009, 11:43:39 am
matching 453 prefixes  ;) alloy strap tank etc

he said they sat too low so they put in the yza250 forks, and im sure he said the ratio or similar in the box were changed to make it more responsive ? cant really tell you about the insides its just what he told me, i dont intend pulling it apart.

it was a race bike in the day, Run by a dealers kid in the riverland so im guessing it was all done for the right reasons.

Just loks like a smal YZ but with a smaller mx250 motor with the bulby bit
Title: Re: 1975 Yamaha YZ125b
Post by: frostype400 on January 03, 2009, 11:48:27 am
freaky did you get the pm i sent you last night thanks Michael.
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 03, 2009, 11:54:33 am
Yes i sent you one back
Title: Re: 1975 Yamaha YZ125b
Post by: frostype400 on January 03, 2009, 11:55:15 am
yeah i got that i sent you another i think
Title: Re: 1975 Yamaha YZ125b
Post by: firko on January 03, 2009, 12:03:08 pm
Quote
I don't know of a 'better' gearbox for them, unless you slap in a whole 125C bottom end
Naughty boy Nathan, that wouldn't be a very legal thing to do, would it?
Title: Re: 1975 Yamaha YZ125b
Post by: Nathan S on January 03, 2009, 02:50:04 pm
Indeed - if I'd been suggesting that fitting the C bottom end was a good/legal idea, then my wording would have been more like "Just use a C bottom end".
Title: Re: 1975 Yamaha YZ125b
Post by: Maicojames on January 03, 2009, 03:29:12 pm
Here in the US, the 1975 YZ125 was still a twin shocker, the 250 and 360 B wre, of course the 1st year monoshock YZs. ..and yes a 125 A ( or  B for that matter) were little more than mx 125s. Still, my friend put an nos Noguchi kit on his in late 1992, and while it only went about 4 races-it flew. We wanted to put a C engine in it, but it was illegal, so sold the C for chump change..if only we could go back and correct our mistakes.....
Title: Re: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 03, 2009, 06:01:22 pm
nah Freaky not chasing one but was interested in the "strage" model.  Busy getting the 360 sorted a bit better so I can flog your arse again at the Nats this year!!!!!

 ;D ;D

Rossco
Title: Re: 1975 Yamaha YZ125b
Post by: albrid-3 on January 03, 2009, 11:48:48 pm
hello Fellows
I have a friend in Colac, now he is a yamaha guru, his father was the yamaha dealer in the 60`s and late 80`s, now ross has all the serial numbers for yamaha, if you need a contact number l can help. call me 0422 309 522
thank you
dav
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 04, 2009, 11:12:59 pm
I cant say the 125 does anything for me, the 250 or the 360 on the other hand does. you wana swapped that flogged 360 of yours for this nice little 125 here then Ross ?
Title: Re: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 05, 2009, 11:44:26 pm
thanks Freaky but my flogged 360 goes well enough to stay in front of you so I might keep it for a bit longer eh!

Are you going to the Nats this year?
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 06, 2009, 12:08:22 pm
nah too far and got sick of all your whining Rooss  ;D,

 i stall into turn one ,you pass me in one race  and i still never hear the end of it.  :P time i bring out the final standings again i think   :P but from memory i was p8 to your p13 ? unlucky for some huh ;)
Title: Re: 1975 Yamaha YZ125b
Post by: Rossvickicampbell on January 06, 2009, 02:27:09 pm
so true Freaky, so true - at least until the next time!

Rossco
Title: Re: 1975 Yamaha YZ125b
Post by: Freakshow on January 06, 2009, 08:55:40 pm
there is always a next time.  if i could get a bike up there id fly up , just aint got anyone up that way i can lean on for a ride to borrow.