Before you can race any motorcycle, you must get it ready for the track. See the Rules page for links to the rulebook, which has full prep information. There is NO shortcut for this; read the rules! Most preparation can be done in a single evening with basic tools and safety wire/safety wire pliers.
There are a number of easy and inexpensive formulas that are competitive within the series; all of these will get you racing with an absolute minimum of effort.
An important thing to remember is that any lighter or smaller-displacement motorcycle can enter a heavier class when permitted by the rules. The smaller the motorcycle, the more racing you can do!
The Formula 125 class is intended to allow most 125 minibikes sold as street-legal to be immediately competitive. Honda Groms, Kawasaki Z125 Pros, Kymco K-Pipe 125s, SSR Razkull 125s, and Benelli TNT 135s need some safety wiring, a catch can, and removal of street equipment and you're good to go. An aftermarket exhaust is optional, and most suspension work is unnecessary.
The YCF SM F150 meets all of our technical requirements for the Formula Middleweight class out of the box, sliders and everything, with only some basic safety prep to do before it is ready to go racing. At 150cc, the YCM SM will be competitive from the start in the FMid class. In the Washington/Oregon area, Adam Black with HH Performance in Newberg, OR and South Sound Honda in Olympia, WA are the local YCF dealers. YCF motorcycles are also available online directly from Wholesale Cycle.
The Kayo MiniGP MR150 is a Honda CRF150F-based GP-style minibike that should be immediately competitive in the Formula Middleweight and Spec 150 classes. For smaller riders or those who prefer a GP-style ride over the supermoto-style configuration of the YCF 150 SM.
The Ohvale series is another set of turn-key motorcycles that will be competitive with zero or near-zero modification required. Although there are some challenges to running the Ohvales in the endurance race (mainly fuel tank size), our 2019 results show that you can definitely be competitive on them. An Ohvale GP-0 110 can race in Formula 125, GP-0 160 in Superbike, and GP-0 190 in Open. For the sprint races, an Ohvale should be hard to beat in it's class. To purchase or rent an Ohvale GP-0 for a NorthWest Mini Moto race, contact Forza GP.
For minis racing in the Open endurance class, the most successful solution to date has been the Honda CRF150R, various 85cc two-stroke motards (Honda CR85, Yamaha RM85, Kawasaki KX85, KTM 85 SX). For our tracks, 17" wheels are favored although 12" wheels have had some success. This can be a very expensive build, but thousands of laps have proven this to be a very effective formula for Open.
The Ohvale GP-0 190 and GP-2 190 have also been competitive in the Open class sprint races, but are hampered in the endurance due to gas tank capacity.
Kawasaki KX65 on 12" rims (Formula Middleweight)
Yamaha TTR-125 on 17" rims (Formula 125) with a YZ85 front end.
Honda CRF150R on 12" or 17" rims (Open Mini)
Aprilia RS50 (with and without a 75cc overbore)
Various scooters - we've had a wide variety!
Almost anything! We've had an Open-class RM85, TTR-125, SSR pit bike, and KX65 all finish within 5 laps of each other in spots 2-5 at the end of a 6-hour endurance race.
If you'd like to build your own racing mini, there are an almost-endless combination of platforms and parts that can lead to endurance and sprint racing success. Below are some common resources for building up a mini racebike:
The Mini Moto Alliance Facebook group is a great place to ask questions about building a mini, what parts and formulas are popular, and connect with others who are racing, building, buying, and selling mini moto race bikes.
MiniMob Racing has a huge selection of parts for a variety of racing minis - https://www.minimobracing.com/store/. For insane XR100 builds, these guys have all the Takegawa Superhead +R parts you can afford.
TBolt USA for engine parts, chassis parts, and SSR pitbikes - https://tboltusa.com/
GatorRimz for wheels and tires - https://gatorrimz.com/
CRFs Only has brake kits for Honda CRF150Rs/CR85s, and motor parts for CRF100s and CRF150Rs - https://www.crfsonly.com/catalog/index.php
Fine Turn Precision out of Tacoma makes custom no-drill front axle sliders and many other custom parts for a variety of minis - https://www.facebook.com/Fineturnprecision/
MadLabs - sliders, brake kits, and more for a variety of minis - https://www.facebook.com/pages/category/Community/MadLabs-1510672099237488/
For the truly dedicated XR100/CRF100 enthusiast, https://japan.webike.net/ has everything under the sun, especially if you can read Japanese.