VFR 400 building a race motor

[boyracer34]

Hi folks, an open question regard a VFR 400 race motor (re)build
Ideas from spark to exhaust. Your have tos, should do and don'ts
CC limit for me is 420cc.
Currently belting a stock motor of unknown vintage, but intend on a rebuild end of season.
Power is king.
( I looked for search but no find, links to threads also appreciated)

[lukemillar]

One question - how much do you want to spend?

[Maelstrom]

http://mngforce.typepad.com/

[boyracer34]

fair question i guess.
i have seen some VFR400s make GSXR 750s look slow at Phillip Island (good riders too) and cannot comprehend what they have done to their motors, very fast bikes.
If I pull mine apart, I am looking for a reasonable gain in horsepower and to maintain reliability.
Two locals have faster bikes in a straight line than i with not over the top mods.
stock bore, mild head work, new valves, replace worn bits, HRC airbox, exhaust can etc.

Its the must do list and if you can do list i need.

[boyracer34]

just started reading your blog Luke, fab info.

[lukemillar]

If you are chasing power then I would do the one thing I haven't/ can't do and that is going big bore. Will definitely get you the most bang for buck

[boyracer34]

Same here luke
whilst the P6 500 class in Oz is 500cc the GCRs also say bore must be no more that %5 more than factory spec., so a 440 kit (by the strict rule) is out.