Over a decade ago the Pro Street class was run almost exclusively by Hayabusas. The class needed some diversity and class rules for the liter bikes were opened up to try and encourage liter bikes to join the party. This gave the liter bikes basically a blank canvas to do what they wanted to build a competitive machine for the class. The rules for the Hayabusas still remained heavily restricted though.
Back then, the rules allowed the Liter bikes to run any fuel they wanted while the Hayabusas could not, the Liter bikes could run 3-4” longer wheelbase than Hayabusas, the Liter bikes could bore and stroke their engine to any size motor, the liter bikes could run over 100 lbs. lighter than a Hayabusa, the Liter bikes were 2” ground clearance and the Hayabusas had to be 3” ground clearance, the Liter bikes were at 20” seat height and the Hayabusas were at 22” seat height, the Liter bikes could run autos that the Hayabusa were not allowed to run, and the Liter bikes could run Nitrous and a Turbo where the Hayabusa could not.
Once a few teams spent time and energy on the Liter bike program, they became a force to reckon with. Then eventually they had a dominant advantage because the Hayabusas were handcuffed to rules and the liter bikes were not.
In 2019 the Liter bikes lost an inch and we added a little weight to help close the 100+ weight gap between the Liter Bikes and the Hayabusas, and we capped the Liter bike displacement at 1125cc. This year we have seen that did nothing to help achieve the parity the class needs with the heavily restricted Hayabusa combos.
So, we have made a few more rule revisions effective for the last XDA race on Sept 18-20 that teams can get changed over the next 2 weeks at their shop before the last XDA event. The Liter bikes will lose 1” of wheelbase for the last event. We have also deducted 25 lbs. from the Hayabusas along with giving 2 more inches of wheelbase to the Hayabusas and allow them to run the same auto transmission as the Liter bikes.
We are hoping that this change will attempt to help close the rules gap and bring these combos closer together in performance.
Currently the Liter bikes and Hayabusas are now all limited to the same fuel, the Liter bikes and Hayabusas are allowed to the run the same auto transmission options, but the Liter bikes are still 2” longer than the same weight rider on a Hayabusa, the Liter bikes are still 75 lbs. lighter than Hayabusas, the Liter bikes are still 1” lower ground clearance and 2” lower seat height.
The new PST revisions for XDA on Sept 18-20 will help close the gap in the class for better side by side racing, but there is still more work to do on the rules this winter when teams will have the time at their shops to make the changes that are needed to achieve parity in the class for 2021. Next year all Turbo Liter bikes and Turbo Hayabusas will have the same ground clearance and same seat height rule. There could be some other changes, but we need to see how things pan out for the rest of the season before committing to any other changes.
To view the current PST Rule Revisions, click here: https://xdaracing.com/rulebook/2020/prostreet.pdf
For more information about the XDA, please visit www.XDAracing.com
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