These pre sale domes will ship with the  pre sale heads. The heads come with a dome and are selected in that item. Only purchase these if you want extra or additional options to try.
 
These dome only fit in our aftermarket billet head for the 99+ YZ 250
 
Dome Descriptions this covers stock and big bore descriptions. They have the same feel just a different amount of power between the bore sizes. Each domes described power delivery option can also be further fine tuned with basic ignition timing changes.
Enduro Soft - 87+ octane very broad, heavy torque curve that starts extremely early and pulls like a tractor, but it is smooth and progressive, not snappy or peaky. This dome will have the least hit for casual riding and has the ability to run on low octane fuel for people that live remote areas and have fuel limitations.
Enduro Medium - 91+ Octane It feels strong and snappy right when you crack the throttle, with a big jump in torque very low in the rpm range. The power still comes on progressively and doesn’t get peaky or uncontrollable; it just arrives quicker and punches harder than the mellower Enduro Soft dome. This is the most well rounded off-road dome. Also not a bad option for Vet MX type riding for those looking for less hit out of an MX bike.
Enduro Hard - 91+ Octane a fast, heavy kick right off the bottom, stronger and quicker than the softer enduro heads. Torque builds sharply low down, stays thick through the mid range, and feels strong without being wild or peaky. Great for technical riders that like a hard hit or for those who ride high elevation requiring more power.
MX - 91+ Octane crisp, strong mid-to-top surge that hits hard and carries massive over-rev. The powerband is similar stock but sharp, and aggressive like an mx dome should be.
SX - 93+ Octane power delivery like the MX dome but a slightly narrower harder hitting power band ideal for tighter tracks like SX or Arenacross.
100 - 100+ Octane Super-clean low-end snap, then a ferocious mid-to-top blast that hits harder and revs even higher than a standard MX dome. Razor-sharp, explosive powerband
110 - 110+ Octane Mid-to-top hit is violently hard and very peaky. Massive over-rev past where normal heads sign off
Blank - This dome is fully machined other that the squish/chamber area and left taller for builders that want to cut their own.
Custom - Please contact the shop for custom domes do not order then ask.