How Supercross Pros Get Power from the 2014 Yamaha YZ250F
Yamalube Racing’s Yamaha YZ250F
2014 Yamaha YZ250F Supercross
This past weekend at the third Anaheim Supercross race, Yamalube Star Racing Yamaha’s Cooper Webb earned his second-podium finish of 2014 250SX.
This was went he finished third aboard his YZ250F, a machine that provided him with a few holeshots in his heat races, and one at Phoenix Supercross.
Due to his performances, Webb has 85 points after five of 17 rounds. This places him fourth in the 250SX rankings, 24 points behind the riders that are tied for the lead – Rockstar Energy Racing KTM’s Jason Anderson and Troy Lee Designs/Lucas Oil Honda’s Cole Seely.
And though racer victory’s aren’t achieved from just a great start, those starts tell much about an engine’s performance. And the 2014 Yamaha YZ250F feature’s Yamaha’s reverse-cylinder design, which has a unique power delivery, helping with these holeshots.
To understand more, Yamaha recently interviewed Yamalube Star Racing Yamaha’s engine guru, Brad Hoffman. Following is the interview courtesy of Yamaha.
Q. Power is at a premium in the 250 class. How much time have you spent working on the YZ250F power plant in general?
Brad Hoffman says: “Basically I’ve been with the team since 2003, so really been working on it since then.”
Q. So, you’ve been working on these engines basically since they were introduced…
Brad Hoffman says: “Yeah, pretty much.”
Q. This bike was definitely introduced pretty late in the year, and that had to cut into your development time quite a bit, didn’t it?
Brad Hoffman says: “Oh, yeah, for sure. Without the help of Yamaha – Bob Oliver and Dan Rambert – it would’ve been a much more difficult task, that’s for sure. We all worked on this together, and they were instrumental in making the gains we needed with the late introduction of the bike. We all put in a lot of hours in a short period of time to pull it together. We can’t thank them enough. And Keith McCarty over at Yamaha pushed really hard to make everyone come together, too, from Yamaha Japan, KYB, here at Star Racing, and Yamaha USA as well.”
Q. What was the biggest difference with trying to get more power out of this new engine?
Brad Hoffman says: “I mean, I don’t know if there’s really a huge difference in how you go about it, but the design of this engine is just so much more rewarding. You do the same amount of work to this engine and the gain is like twice [what you would gain with the previous engines]. If you did the same exact thing to the old engines that you did to this one, it’s a huge difference. And it’s not necessarily because of the four-valves, either…”
Q. So, is it the way that it brings in air that makes a huge difference there?
Brad Hoffman says: “Yeah, I think the reverse cylinder head allows the intake port so much of a straighter shot to the combustion chamber. That’s what makes it the best design that there is.”
Q. In the 250cc class nowadays, people push these engines really, really hard and they’re known not to last very long under that kind of strain. Is the ease that you can find power also helpful in keeping the engine reliable at the same time?
Brad Hoffman says: “Yeah… I mean, honestly, they don’t always become unreliable. I think a lot of it is just sometimes, if everything is not right in terms of parts design or fit, it could cause problems. I think, when you get everything just dialed, like doing the high-performance engines for motocross, they’re pretty reliable. They’re definitely not maybe as reliable as stock or whatnot, but durability and power should go hand-in-hand if everything is done right.”
Q. What do you consider to be the difference in the value of dyno-tuning as compared to track-tuning? And what’s the bigger priority?
Brad Hoffman says: “I feel like as long as you know what you’re looking for, and obviously we’ve been doing this a long time, the engine guy gets a feel for what he can get away with on the dyno and what he can’t. So, as long as you know what you’re looking for on the dyno, the dyno’s a ‘you can’t live without it’ kind of thing. It’s definitely a good tool, ,but if you get carried away looking at one thing, like the peak number or something all day long, you could definitely go in the wrong direction. But as long as you know what you can sacrifice and what you can’t, the dyno is a really good tool.”
