Hi
I run in class FSR-V 27(M track) with one RCMK RZ254 engine . I started to feel pressed by the TK engines .
What tuning options I have : Tune the RCMK , or I change it ?
Tuning options
Long Stroke Crank ?
Modify the ports in the cylinder ?
Power Spark?
Thanks for you answers

Razvan

If you have to be 27cc look at this kit

Don't think they will work on RZ but if you go side exhaust these will work

www.gizmomotors.com/index.php/...-mod-kit-detail

This one makes it a 29.5

www.gizmomotors.com/index.php/...-cyl-kit-detail

I think J&G makes a rear exhaust modified cylinder
www.jg-motors.com/Page_5.html


Have Fun

Randy

Thanks for your answer Randy
But I must have 27 cc .
J&G top end kit Is perfect but cost more then one TK to Gizmo
I first try to tune the RZ .
Ideas?

Race and have fun

Razvan

www.modelgasboats.com/magazine...-engine-porting

Maybe here

Randy

Any rear exh. non sleeved engine is a poor design. The power stroke of the piston thrusts hard on only the tiny transfer divider, and wears the pistons very quickly. The RCMK components are very strong, but the pistons will suffer. The K30 has a half sleeved cyld. and is better, but the displacement is too much for your class.

If you stay with the RZ, you can use the MK + 1mm. stroke ( 29mm ) crank to raise it to 26.33cc, or if you can find a non reduced (straight) TK + 1.6mm stroke ( 29.6mm ) crank, it will raise it to 26.87cc. The squish ( piston to head clearance ) can be adjusted to .010", the exh. timing to 185 - 187 degrees, and the int. to 160 degs. A "properly" modified 1048 carb should be the minimum size.
A Zenoah flywheel is lighter, and can be further lightened by .080". Gap your plug to .015"