[cotswold]

Hi Guys,
I am building a 50cc race bike using the NSR50 engine. I have put up some pictures of where I am at.
So far I have opened up the intake to accept a CR80 reed block and 28mm carb, I will be using Boyeson 2 stage reeds. I have cut some boyeson ports into the cylinder and the exhaust port is widened and lifted to 198*, the transfers are standard height but widened to keep the blow down at a reasonable number. The crank has been rebuilt using a modified prox rod with a nice silvered bearing. The crank cases have been opened out and matched to the cylinder. I am using a piston out of a KTM water cooled 50 which has a lower deck height so the head has been machined into the cylinder with a squish of .06. I have a PVL ignition with a 16* slide, the oil pump is gone and am thinking of removing the water pump and running an electric one.
So any thoughts, what have I missed?

 

[cotswold]

I made up a bell mouth for the carbie and will try this N-plan pipe at first but will have to get one built to match I imagine.

 

[cotswold]

I plan on fitting the engine into my Honda RS125NF4 chassis, I have a single sided swinging arm out of an Aprilia to go in as I have one and spare wheels

 

[PocketBikeRacingTsmmr]

Wow!! Very Cool ...it's gonna be sweet

 

[cotswold]

dyno chart for nsr50

just put her all back together in the Aprilia RS50 chassis and put her on the Dyno.
only did 3 pulls but got 13.8 bhp at the back wheel so not too bad, more to come as it still runs the standard head which is rubbish

 

[cotswold]

The 50 in action, 5 lap sprint used as a set up for the points races

 

[PocketBikeRacingTsmmr]

Awesome I love the sound when it hits the power band sounds amazing

 

[Luckystar64]

It's pretty cool, but why not just run an Aprilia RS50 complete bike? I love those things, and I've been thinking about doing one-- or possibly a Canadian model CBR125. Parts shouldn't be too hard to get here. -L*64

 

[cotswold]

I was given an MTX50R honda and decided to build a race bike out of it, the frame was rubbish so looked around and found the old Aprilia rolling chassis for not many Dollars so decided to join them together. The Honda motor is very strong compared to the Aprilia although it would be easier to get the RS50 parts than the Honda as I have had to make just about every thing for the build.
This is what is happening next

I have been given a set of diagrams to get the motor on point

I will post up the dyno run when this bit is done