Big Bore Kit, NSR300, Wiseco, VHM *

Description

Big Bore Kit, NSR300, Wiseco, VHM *

This 300cc Big Bore Kit is identical to the TPER-0007 300cc Big Bore Kit, but the standard 300cc heads and pistons are replaced with high performance options.
In this case we have forged Wiseco pistons that are lighter and stronger than stock, and also changable insert VHM cylinder heads, which have been specifically developed by TYGA and VHM for use with the TYGA 300cc Big Bore Kit.
See below for performance details for TPER-0007.
Bore & Stroke is 59mm x 54.5mm giving a total displacement of 298cc.

Parts included in the NSR300 kit.

* Cylinder x 2 (includes head studs, RC valve, pulley & nut and washers)
* Rear Head x 1
* Front Head x 1
* Piston x 2
* Ring set x 2
* Piston Pin x 2
* Piston Clip x 4
* S/E Bearing x 2
* Head gasket x 2
* Cylinder gasket x 2
* RC Valve cables x 4
* Water hose x 1
* Exhaust Manifold x 2 (to fit TYGA pipes)

Please request your piston preference in the order comment box:

Short Skirt (default):
The short skirt type piston is a ‘bolt on’ solution for the big bore kit. In this case we modify the piston by shortening the front side skirt to allow clearance from the crankcase at BDC. Therefore, no crankcase disassembly or modification is necessary, and the top end can be assembled in the usual way of doing a top end overhaul.

Full Skirt:
The full skirt type piston has a very slightly increased longevity compared to the short skirt type, however, this necessitates that the crankcase is completely disassembled, and some grinding of the crankcase is required to allow for piston clearance from the case at BDC. Please see the guide for how to perform the necessary modifications.

Other information:

There is no problem about the RC valves hitting the piston due to thin cylinder wall thickness. This is not an issue on our kit as it’s using different
cylinders, not modified NSR250. They are genuine OEM Honda cylinders, made and plated in Japan to their typical high quality.
The RC valves are easier to adjust than ever on the 300 kit, as there’s only one adjuster screw to play with, and each cylinder marked at the correct ‘fully open’ position for simple setting.
Exact Jetting requirements for your area and application cannot be provided due to differing atmospheric conditions around the world. However, following are some base settings to work from:

• MC21 Std bottom end, Wire splice, TYGA Pipes, Airbox lid mod with filter.
  Temp: 29 C
  Press: 1015mb
  Hum: 65%
  Alt: 30m
  MJ – #182/#185
  JN – Std./Std.
  SJ – #38/#38
  AS – 1.5 turns out
  PwrJ – Std./Std.

Tip: Cooler temps, higher pressure and/or lower humidity require richer jetting. High altitude requires leaner settings. Starting off with rich settings will in the worse case foul a plug. Too lean a setting may destroy the engine.
This jet set-up is for guidance only. TYGA Performance cannot be held responsible for any engine damage incurred due to incorrect settings.
This kit is available by special order. Each kit takes approx. four weeks to prepare.

Fitting Instructions RC Cables

There is no problem about the RC valves hitting the piston due to thin cylinder wall thickness. This is not an issue on our kit as it’s using different
cylinders, not modified NSR250. They are genuine OEM Honda cylinders, made and plated in Japan to their typical high quality.

The RC valves are easier to adjust than ever on the 300 kit, as there’s only one adjuster screw to play with, and each cylinder marked at the correct ‘fully open’ position for simple setting.