2 Strokes Down Under

hi all,i was given a bunky rz 500 rolling chassis complete minus plastics
i have a stock rz 500 already but want do something useful with this one, i dont want a stocker, so question...what are the simple things that can be done to get say 100 neddies from the motor to drop in the other frame.....your turn

100hp is not really "simple" on a 500, but here would be my list of easiest methods:

- Set up the squish properly
- good set of pipes
- Programmable ignition and power valves (zeeltronic etc)
- Reed cage mod (rz350 cages, modify standard cage etc)

There are others, such as making new manifolds to replace the small 90 degree bends on the standard ones, and some port work, but these are probably the easiest mods I guess.

i was thinking maybe a bit of port work, jollys/lomas, zeeltronics

Buy a well maintained TZ/RS 250, they will make almost as much HP but weigh a little more than the RZ 500 engine.
Problem with a 4 cylinder is...............well there is 4 of everything ! Before adding 20HP I always advise to ditch 20kgs or weight, then add 20HP.
The cylinder it's self would be capable of 30HP easy, but that comes at a cost ie maintainence intervals come down.
With everything there is a trade off, more power = more heat, so be sure your cooling is up to scratch(especialy the LH upper if my RZ500 knowledge correct)

Both the uppers have cooling issues, but there is a pretty simple mod you can do to get more cooling around the exhaust port.

ritza wrote:i was thinking maybe a bit of port work, jollys/lomas, zeeltronics

Mine has had some port work done, but to be honest, for the money I think you're better off doing other things first. If you know someone who can do it cheap for you, then go for it, but there can be quite a few hours in a good job.

Mine were done for me by a top bloke in the UK (Mick Abbey - better give him a plug).

i used 100hp as a random number, the bike has a complete motor and pipes etc. so it is more a throw it out there and see what comes back question

The answer is how deep the pockets? There plenty of simple things to do to the engine but to make 25HP per cylinder will take a wee bit of work. Which is a snack really, the real trick is to have a 100HP at peak and 50 at 3000, everything must match the gearbox. Very easy to build peaky engines but flexible engines with a wide power spread that are easy to ride fast,take time and effort.

I'm currently running around 92HP on my RZ500 with stock porting and stock airbox.
This was done by raising the compression and setting the squish.
New pipes (jollys).
Advancing the ignition 5 deg and rejetting.

Ditching the original pipes saves around 10kg.

I saw a report out of NZ that with pipes an ignition and careful setting up on the dyno got 120RWHP...........nice