MOTEGI, JAPAN, SEPT 30 - Fiat Yamaha's Jorge Lorenzo and Valentino Rossi will have upgraded engines at Motegi in an attempt to close the speed gap on the other manufacturers, but Rossi, for one, doesn't think it will be enough.The Yamaha YZR-M1 has consistently been slower than the other brands, especially the Ducatis and Hondas. Lorenzo has been able to minimize the damage, but the Honda RC212V has gotten stronger as the season has progressed. In the last three races, Repsol Honda's Dani Pedrosa has two wins and a second and Ducati Marlboro's Casey Stoner won the last time out in Aragon, a track Rossi said was the M1's worst of the year.By finishing behind Pedrosa three races in a row, Lorenzo has seen his points gap shrink from 77 to 56 with five races to go, including this weekend's Japanese Grand Prix. Lorenzo said he wasn't "able to relax, but I am in a great position, although we are not in the best shape technically because we have have a small power disadvantage and Yamaha are working on this and here we have a new evolution of engine which should help me. But I think even with the same condition we've had in the last two races, I can make a better result than Aragon, which was a special race. If everything is normal we can be fighting for the podium or a victory."Rossi said he'd gotten assurances from Yamaha that he'll get the same equipment as Lorenzo as he winds down his career with the company. The nine-time world champion, who's moving to Ducati next year, said that he'd been told "that my bike and the bike of Jorge is same to the end of the season and bring one each, the engine. We try in Brno" at the post-race test "and it was a small improvement, so we expect to be a little bit closer to the other manufacturers, but I think it is not enough for arrive at the same level. But I hope in these three races our bike suffers more compared to Aragon, that is for sure the worst circuit for the M1."To Stoner, the most interesting thing is whether Yamaha will run out of engines. Lorenzo has already used five engines. Rossi, because of his injury, has used one less. Each rider is only allocated six for the season."Already they are using another new engine here this weekend and they're going to be close to their limit with five races to go," he said. "So maybe they have to use one extra engine and maybe this is where Dani can make the real damage."But we're not sure yet, we'll have to see how the season goes on. Jorge's been strong all season. I mean, I know Dani's situation, you have to be at the front every time without any mistakes. If you make a mistake then Jorge will take the points and run away with the championship. So for sure it's going to be interesting to see in these last races, but Jorge's done a fantastic job all season; I don't see why he can't finish the season like this."