Boarce: Project bike: 1979 Yamaha RX125

The bike

Engine: Single cylinder 125cc 2 stroke
Brakes: single disc front / drum brake rear
Top speed: around 80km/hr
Status of mine: currently not running

"To do" list

I believe my bike is not running due to either bad fuel (it hasn't been run in years) or the battery is done and dusted.As such.. next up on the to do list...

New battery
Flush fuel system
Ride :)

Have done

I'll be keeping the bike fairly close to stock but so far the work (including maintenance) I have done on the bike is listed below. I'll point to guides/articles/etc for anything that I feel warrants it. If you have any queries, feel free to ask!

Pulled front brake caliper apart - removed piston, cleaned inside caliper - bled brakes.
Replaced spark plug
Removed stock bars and mirrors and replaced with drop drag bars and bar end mirrors

This bikes background

I bought the 1979 Yamaha RX125 as a little light intro into bike maintenance and also to commute on when tearing down my primary commuter bike the FZ6N. It was also to double as a small easy bike for my gal to learn to ride on if she ever gets around to getting her bike license.

My original intention was to get a beat up bike and do some basic restoration on it, however this bike turned up nearby for a steal of a price and didn't require much work at all to get it running... it had sat unused in a garage for a couple of years but otherwise has been well looked after.

RD125 General information

While the RX125 is visually similar to an RD125, they're not the same bike by any means. The RD's are Twin cylinder 2strokes whereas the RX is only a single. This is quite evident when you look at the exhausts, the RX only has one as oppsoed to the RD's twin pipes.

The RX125 was never available in many regions, in fact it was only available in Argentina, Australia, New Zealand, Brazil and Uruguay. Which seems to make spares for these old bikes a little more rare than some other more popular 70's machines.

I'm not 100% sure how this works but RS125's appear to be the same bike as RX125's. I'm not sure if there is any difference... if anyone knows and can chime in, by all means.

I'm going to list as much information here as I can as I discover it, should I discover any... stay tuned.

4 comments:

PP11 February 2016 at 23:01
Excellent machine the RX125 ! I´ve got one since 1980 , original, with 13.000 km.Its top speed is about 125 km/h.The Rx is the same machine as the RS DX .
DX stands for the front disc brake.In Europe there was two versions of the RS , the one with front brake disc ( DX ) and the one without disc ( RS alone ).
In Australia, Argentina, and Uruguay , the only model made for this markets, was the RX , that is to say that all this machines got front brake disc.
In Brasil and Colombia you could choose any of the two models , with or without front brake disc.
First models has brake points , from 1982 onwards they had CDI.

Greetings from the city of Buenos Aires ( CABA ), Argentina.

Pablo
Unknown2 March 2016 at 22:11
1980 RX 125 was my first bike , so it was this model that "changed my life". 34 years later iam restoring one that is exactly the same as the one i had in 1981..complete rebuild, new mains, rings,seals,seat,spokes n rims repainted and looking like new .