We test Thumper Racing’s bore and stroked Honda CRF250R to see what an extra 50cc of displacement will give this Lites-class machine. Read the full details in our Thumper Racing/Hot Cams CRF300R Project article.
- For as good as the stock CRF is, we enlisted the help of Thumper Racing and Hot Cams to build us a machine that brings even more to the table.
- As the 2010 Fire/Police Motocross Grand National Champion, Ryan Chapin is the type of rider who can make use of a project like this. We turned the Los Angeles firefighter loose on the Racetown 395 track with a stock CRF250R for comparison.
- In order to give the red ripper a new edge on the competition, a QTM 270mm oversized brake rotor is installed on the front.
- Works Connection parts are sprinkled everywhere, like this Elite clutch perch.
- Handling remains as light as ever - better in fact thanks to the MB1 suspension.
- Despite a larger piston and longer stroke, our tester didn't notice any negative gyroscopic effects.
- The Thumper Racing motor feels stronger all the way through the rpm range. It makes blasting out of corners a cinch.
- Renthal Twinwall handlebars, bar mounts and dual-compound grips form the controls.
- TCR wheel anodizing makes the hubs and rims look factory for a fraction of the price.
- The Honda CRF250R was a good platform to start from and the extra engine displacement and improved suspension made it even better for winning races.
- In addition to the revised suspension, Clark also bolted on a blue CRF450R linkage pull rod from Suspension Direct (part # SDECPRH09) for a more linear curve.
- Hinson takes care of all the clutch internals, though we did still notice some clutch fade.
- Thumper Racing CRF300 Project Bike
- Burnt fuel passes through the titanium FMF Factory 4.1 RCT MegaBomb exhaust system.
- The 300 conversion is sold as a complete kit so that Thumper Racing can handle the case modifications and crank balancing themselves.
- VP Racing Fuels U4.4 gasoline is used to bring out as much performance as possible. VP designed this fuel to work specifically with modified engines and resist the effects of heat near the fuel tank.