WR 400/13:1 compression Wiseco Piston

I've just gat all my parts back to put the wiseco overbore piston in my 400. The only concern I had was:

Are you required to go to higher octane gas (I already use the highest rated pump gas) when you change to the 13:1 overbored piston?

Should I be mixing down race gas? This bike is for fast trail riding only.

unless I am mistaken, you SHOULD(MUST?) run higher octane, aka RACE FUEL.

I ended up at 14~1 on my 97mm kit (444cc).

I found on the dyno the bike loved pump gas.

Race gas offered a minimal gain in HP.

I also ran 1400miles of baja mostly on premium pemex w/no problems.

If it is jetted right I wouldn't be concerned.

The yz-f combustion chamber loves compression.

I would also run the yz base gasket, or the cometic.


Please check your PM's.

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