Shop Talk: HMF Racing

HMF tunes the 

TPR project

YFZ450R

All EFI programmers are not created equal. We learned that lesson the hard way. 

As part of the TPR project YFZ450R build, our exhaust sponsor, Motoworks, hooked us up with their Motoworks FMI tuner so we could adjust the fuel map for our national-level engine mods courtesy ATP Racing Engines.

The Motoworks FMI is a mode-based tuner. About the size of a credit card, mode-based tuners offer a minimal fuel level adjustment range at three general throttle openings: cruise, acceleration and wide open. ATP was able to make the tuner work by running the heavily modified project quad's engine on their dyno in Florida. They spent two weeks last summer on the quad and dialed it in perfectly. 

But this summer we hit a snag when the ground wire on the Motoworks tuner broke during a test session. The loss of power to the unit resulted in the complete erasure of our custom ATP fuel map. Our project quad was dead at the gate.

That's when Cleveland-based HMF stepped up to the plate. As a newcomer to the build, we couldn't work with the exhaust manufacturer to run their new HMF Competition Series exhaust system with TriMax Core Technology. We did, however, run their protective headlight and tail light block-off panels, which have kept our critical electronic components safe from roost and rocks for more than a year now.

First we acquired a DynoJet Power Commander V. The PCV is a much more sophisticated fuel programmer and allows you to fully adjust the fuel levels at every percentage of throttle opening. The PCV essentially gives you complete control of the fuel map. Then, we took the quad to HMF and put it on their DynoJet dyno.

The dyno room at HMF may be small, but it produces big horsepower numbers. Their dyno is equipped with an O2 sniffer, so they know exactly where in the RPM range your quad is lacking fuel or getting too much.

The quad started with DynoJet's downloadable GYT-R stage three fuel map, which is set up for an engine with a full exhaust, intake mods, cams, port and polish and a high-compression piston. Still, initial dyno runs showed the GYT-R Stage III fuel map didn't give the TPR YFZR enough fuel where it needed it.

HMF's dyno technicians made the appropriate adjustments to the fuel table. Their techs were able to smooth out and increase the power curve considerably compared to the stage three map. They also increased over-rev to keep the quad from falling on its face on the top end. The horsepower numbers were about the same as ATP's original 52 horsepower reading when they wrapped up the engine mods last year.

We showed up at HMF with an ailing quad. Their knowledgeable, professional and courteous staff sent our quad home with a clean bill of health, a new, throaty bark and ready to throw roost again. If you're in the Ohio area and are struggling to tune your EFI quad, give HMF a call. You'll be glad you did. HMF also has a full line of services for engine and suspension building, and their retail store is packed with exhaust systems, suspension and chassis components.

CONTACT: Website: http://www.hmfracing.com/      Phone: 216-631-6980