Colin Edwards led the American challenge during Friday practice for the US Grand Prix at Laguna Seca, but ninth position was far below his expectations.
The 35-year-old Texan, second in the 2005 US GP, encountered some front and rear suspension issues but was within 0.6sec of fourth placed Dani Pedrosa - the rider whom he is currently tied with for fifth in the world championship.
"It wasn't the great start to my home race I was looking for and the bike feels just way too stiff," said the Monster Yamaha Tech 3 star. "The main problem is in the hard braking because I've no feeling with the bike bouncing around on me. There's just not enough movement from the suspension.
"When you've got the handlebars moving and up and down and the seat moving up and down it's obvious the suspension is not absorbing the bumps enough. There are some huge bumps out there and today it felt a bit like motocross. So we'll soften it up for tomorrow and make the suspension react faster and let it move more freely rather than having a jerky and bouncing sensation.
"It feels like there's a second waiting right in front of me but I'm a bit handcuffed at the moment. Once we fix these issues, and I know we will because my guys at Tech 3 are awesome, I'm not going to have to push and hang it out to find the time. I know it will come immediately as soon as we get the bike working.
"I'm confident we can find what we need and put on a good show for the American fans and for Monster's home race," he insisted."
Team-mate James Toseland finished in 13th place, though he was less than a second off sixth in another close session.
With Fiat Yamaha Team director Masahiko Nakajima again helping the 28-year-old this weekend, Toseland will work hard with his team tonight to find a setting to improve rear grip ahead of Saturday's qualifying session.
"The position isn't that great but I feel like it was a pretty decent session. We've got a bit of work to do but there is no need to panic," said the Englishman, who claimed a joint career-best sixth last weekend at Assen.
"We're just missing a bit on the set-up really. I'm lacking a bit of edge grip on the harder rear tyre, and that is the one we're going to have to race with looking at the temperature.
"This track isn't quite as good for grip as Assen and we know what we've got to do to get more grip from the rear but we just ran out of time at the end of the session. And I'm still adapting to the new set-up we had in Assen because that changed the balance of the bike quite a lot.
"With the tighter corners and the undulation it just takes a bit of getting used to being so different to Assen. I'm confident with the bike a bit more comfortable that I can go quite a bit faster and be up there challenging for a good result for Monster in what is a massive race for our sponsor," he concluded.