MX 125 D model

[vandy010]

my cousin had a near new one given to him in about 82~83~ish... in Brisbane QLD.
it was the first time i'd even seen or heard of one.
i have a frame only but will throw a few YZ125C/X parts at it with an RM125A swingarm to turn it into a complete bike.
rare? yes...

[Slakewell]

So I take it that YZ parts bolt directly onto the engine?

[TM BILL]

Sure do  or if your really keen a YZ 125D motor will drop right in and is still pre 78 legal but does away with that stupid 2 part gearshaft arrangement .

[kdx Geoff]

Bill, thats a copy of the one original brochure l have, not an original brochure.

l just wanted to make sure we're talking about the same thing ?

Geoff

[TM BILL]

Bill, thats a copy of the one original brochure l have, not an original brochure.

l just wanted to make sure we're talking about the same thing ?

Geoff

Yeah Geoff a copy would be great just let me know what I owe you .

Thanks Bill

[Slakewell]

Interesting pre 78 racer if you add aftermarket barrel and head make up a nice pipe and fit a 34mm carb. Sexy little bikes IMO.

[mposs]

One more ....

[Nathan S]

So the register is:
Bill's (NZ);
Rusty's;
TT5 Matt's;
Vandy's;
Mposs'.

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Motor is basically a mix of YZ-C and YZ-X. The head has a unique 565 casting - I can't remember what the differences were, but they were minor.

[cr4ever]

There is one MX125C here in South Australia, the owner was racing it in DT/VMX but when he realised how rare it is he put it away as it's very nice. I never even knew they existed until I saw it. Freaky knows the owner.....

[Slakewell]

If you played the money is little obstruction , you could get GMC to build a nice chrome molly version fit a RM B alloy swingarm , fit YZ D engine upgraded with noguchi barrell and head,YZ front end etc . be a very cool little bike. 

[Iain Cameron]

Another nice bit of gear is the YZ175c , same story very low numbers . There has been a YZ175 cylinder on Aust evilbay for a while now but it will not fit onto the 125x motor like most of the dt 125 \175 the YZ175 had different stud pattern . http://www.ebay.com.au/itm/YAMAHA-1976-YZ175C-New-Cylinder-/271250425283?pt=AU_Motorcycle_Parts_Accessories&hash=item3f27c905c3    Iain

[Slakewell]

Would these be pistons to fit?
http://www.ebay.com.au/itm/Yamaha-Fs1-piston-noguchi-motors-yokohama-/300715843702?pt=UK_Motorcycle_Parts_13&hash=item46040fa076

[Slakewell]

What is this odd motor beastie thing? A Yamaha fitted with no work so good ignition ?
http://www.gumtree.com.au/s-ad/gaven/parts/yamaha-yz125-b-motor-1975/1022608705

[Nathan S]

Yeah, that'd be a Motoplat molesting that little Yammie motor.

537 = YZ125C.

[Scootern29]

Since this has morphed into an MXC thread, here's some questions I have and maybe you guys have the answers.

The little C had a 30mm small body carb on it stock which I was lucky to find. Would you just change the manifold for the larger carb? The reason I am asking this is that when I got the bike it had a 26mm carb rigged on it. I did not have enough room to fit a 34mm with the manifold I had because the carb hits the case and changes the airbox inlet. Would you machine off the drain cap for clearance on the case, or? Would you run a sock or pod air filter?

I am only asking in case I run across another C.