View Full Version : RS50 w/yz125 swap (re) Build

09-13-2013, 07:13 PM
I've been lurking on here for about 2 months or so, getting inspired by various feather weight bike builds. Two builds in particular caught my attention the most, Mattology's CR and nidyanazo's YZ. I had to have one for myself! While searching for a suitable donor one late night on BARF, I found a 3mo old for sale thread for an RS with a YZ125 already in it!! Lucky for me it was still for sale! After getting pictures from the current owner I realized that this was the bike nidyanazo had built! http://www.bayareatwostroke.com/forum/images/smilies/teeth.gif Going to see the bike reviled that two years of sitting had taken their toll on the bike. But the price was right, and I decided since I had planed to scratch build my own, taking this one apart to re-make into the perfect bike for me, would be no greater of an undertaking... (Hopefully)

Pre swap 2010: http://www.bayareatwostroke.com/foru...ead.php?t=2791 (http://www.bayareatwostroke.com/forum/showthread.php?t=2791)
nidyanazo's build 2011: http://www.sportbikes.net/forums/gen...a-project.html (http://www.sportbikes.net/forums/general-sportbikes/446159-new-2stroke-mini-gp-replica-project.html) http://www.bayareatwostroke.com/foru...ead.php?t=3061 (http://www.bayareatwostroke.com/forum/showthread.php?t=3061) Build for sale 2011: http://www.bayareatwostroke.com/foru...ead.php?t=3085 (http://www.bayareatwostroke.com/forum/showthread.php?t=3085)
For sale again 2012: http://www.bayareatwostroke.com/foru...ead.php?t=3201 (http://www.bayareatwostroke.com/forum/showthread.php?t=3201)
BARF ad 2013: http://bayarearidersforum.com/forums...highlight=rs50 (http://bayarearidersforum.com/forums/showthread.php?t=431418&highlight=rs50)
First time I've had so much of a vehicle's history


09-14-2013, 01:34 PM
Going over the bike in detail is what convinced me I needed to start over. I plan to track this bike so strength to endure the rigors of road racing is what I'm after. After two years of sitting, rust had set in on nidy's motor mounts http://www.bayareatwostroke.com/forum/images/smilies/thumbdown.gif
The original build had utilized the stock aprilia mounts with flat bar steel adapters. I'm using a mounting strategy similar to Matt's where I have taken a section out of the swing arm and use the YZ rear mount with the RS's swing arm pivot bolt as yamaha intended, with the forward mounts being welded to the cradle. I will also have to come up with a new mounting system for the radiator as zipties aren't going to cut it at the track. http://www.bayareatwostroke.com/forum/images/smilies/ride.gif


09-15-2013, 07:42 AM
Good luck with the rebuild.

12-14-2015, 10:21 PM
Hey guys,

Selling the complete engine swap with supporting conversion parts from my fire breathing hybrid

* 2000 Yamaha YZ125 engine (starts first kick!)
* YZ125 stock carburetor, tuned
* YZ, running electronics, coil, etc.
* RS50 modified engine cradle subframe for YZ125
* Arrow brand RS125 full exhaust.
* Arrow carbon/kevlar silencer
* Machined aluminum swingarm spacer
* Swingarm bolt-sleeve (rear motor mount)

*Modified swingarm. To complete the swap you will have to "notch" your stock RS swingarm for the rear motor mount. (If buyer covers shipping both ways we can trade for my notched swingarm or I will supply you with measurements for your cutting)

With the exception of the swingarm, this is everything you need to convert your RS50 into a RS-Y125! All of the welding and fab work is already done!
ALMOST a bolt in and go!!

Selling to convert to an 85cc to be class legal for mini racing. :ride

Asking $1,800 or best offer Cell: (SixOneTwo) NineOneZero-SixTwoThreeOne

12-26-2015, 07:43 AM
I'm interested in this dude, let me know what's up