Engine dying on me

[Ionatan]

Hi everyone, today I was riding the bike, a little hard I must say, I was at around 7000 rpm 5'th gear, and tried to accelerate and the rpm instead of going up was just staying at 7000 and then going down, and from then I could feel it doesn't have the same power as before when accelerating. Then after 1 km it rides properly again. I couldn't hear any strange engine noise or anything. I have enough fuel in the tank, but the symptoms where something like when you are out if gas and it felt that it only does it in the 5'th and 6'th gear. I have absolutely no idea what it could be. It didn't stop for good or anything.
thanks a lot, hope it makes sense.

[ben2go]

It sounds like the fuel cap vent maybe clogged or partially blocked.It could also be the vacuum operated petcock.It's either not getting enough vacuum or the diaphragm inside is going bad.I would check the vacuum line and try running on PRI if it happens again.If it runs fine on PRI,then it's a bad petcock.I have a write up on replacing the petcock with one that doesn't require vacuum.

http://gstwins.com/gsboard/index.php?topic=56352.0