Problems with Michelin's front tyres on the resurfaced Brno circuit may have left Colin Edwards and James Toseland seventh and 13th during Friday practice - but the Tech 3 Yamaha riders branded their ungraded YZR-M1 engines as 'awesome' and 'fantastic'.
Having received Yamaha's original pneumatic-valve design earlier in the year, the latest upgrade features an increased rev ceiling and more horsepower.
"The new engine is awesome although it feels a little bit different than what I've been running," said Edwards, who was the top Michelin rider on day one of the Czech Republic Grand Prix. "What I had was obviously developed to the maximum and it was real smooth and real linear with the power delivery. The new motor has a bit of a different feel but it is faster. It's a little bit peaky but its not hurting us at all so thanks to Yamaha for rolling that over here to Tech 3.
"We got some electronics stuff too so that is helping calm things down. It's just a little bit more aggressive on the throttle, which the way I'm having too ride this bike is actually good at the moment.
"With some of the small issues I have got with the front tyre, the only way I can ride is brake as hard as I can and almost back it in like a Supermoto. And as soon as I get full lean angle I just roll to maximum throttle opening because I can't carry lots of momentum with 250 lines like I need to.
"I need to get the rear to come round to steer the bike. The rear tyre feels fantastic and I'm really happy with that. I did 15 laps on a rear without any problems and good and consistent grip, but the front tyre that I normally use and that I love, it is good but only for a short distance. I'll sit down with my guys again tonight and talk things through with Michelin to see if we can improve again tomorrow," concluded the Texan.
Toseland also felt the benefits of the new engine and had forced his way into the top ten with 13 minutes of the afternoon session remaining, but had to settle for 13th after falling at the downhill Kevin Schwantz corner.
"The new engine is fantastic, so a massive thanks to Yamaha for giving the team and me this level of support," said Toseland, who finished first and second in the 2007 Brno WSBK round. "It just feels stronger and you seem to be getting through the gearbox a lot more progressively. And it keeps on pulling once you get into fifth and sixth gear. You see the red gear change light flash up a bit quicker than usual and up the hill you can certainly feel the bike is still pulling and it is a big improvement.
"We have just got a lot of hard work to do with Michelin. Now the track is cleaning up a little we are getting more life out of the tyre and the grip level is not so bad. But we can still make it better and I am staying positive and trying to work as hard as I can with Michelin.
"When I ran off I just braked a bit too late down the hill. I thought I was going to be able to stay on it but it high-sided me in the gravel. It was only a small tip off but then the chain fell off so I had to put that back on. I cleaned it all off and I went quicker on the last two laps even with that.
"But with the front tyre we are just trying to find a combination between having out and out grip and the endurance. You can go as soft as you want to find some grip but you have also got to finish the 22-laps," he explained.