Yamaha's Ben Spies says he was lucky to escape any injury when the swingarm on his factory YZR-M1 broke as he exited Laguna Seca's notorious Corkscrew in yesterday's Californian MotoGP.

The Texan, who quit the team last Tuesday, had just pulled a gap on Andrea Dovizioso and Cal Crutchlow and looked to have secured fourth place but then disaster struck as the swingarm suffered a 'technical failure' and he surfed the Yamaha into the gravel.

"We were feeling good. I didn't have quite the grip as in the earlier sessions with the hard tyre. We almost went with the soft but then chose the safer option. In the last ten laps, we were starting to pull away and I had a little left up my sleeve," said Spies, speaking at Laguna

"All of a sudden, when I got to the bottom of the Corkscrew, the bike went out from underneath me. I had no control, it didn't even slide or anything. I didn't know what happened at first, I thought I had hit a huge bump but there isn't one there. It's nobody's fault, just more bad luck.

"I went left, everything was fine, I went right got on the gas and as soon as the rear got any load to it, it just completely collapsed but it didn't get the chance to do a big highside, it just kinda slid out from underneath me.

"I was lucky it didn't happen at turn one. If it had happened there or going up to the Corkscrew, I could have been seriously hurt. I'm not mad at Yamaha about it. There's no room for that in this type of racing with this much money in the bikes, something like that shouldn't happen. I'm lucky that, being caught up in the bike like that, I didn't catch a hand in the wheel or the chain.

"All we can say until they do some investigation is it was a swingarm failure but it definitely broke.