Hi All, My bike is a 2007 XT660R. I have read the section on the XT660 low speed fuelling problems & "Kevs Fix" but I'm curious to know if anyone has achieved a satisfactory result from Yamaha, apart from adjusting the CO1 settings on the bikes computer which has been tried but achieved little. Also do any 2008 XT Tenere owners which as far as I know has the same engine, experience this surging problem. Cheers XT Tourer

I've a Z, and I can say there are no surging problems at all. The ECU is different to the X/R and the Tenere has a much larger airbox - Yamaha reckon this is the reason.

However, the 2009 X/R's have a different ECU, and apparently there is no surging problem.

You mention Kev's fix, did you read this on www.XT660.com ?? I'm aware that lots of people have tried to resolve the surging problem, and Yamaha still won't admit there is a problem, curious why they've changed the ECU though.....

Despite having the same power plant as the X/R the Z is a different machine, and as such behaves differently too, also there is the added weight (especially when full of fuel), uprated suspension, better chassis, firmer swing arm, better brakes and more off-road bias wheels that mat well all contribute to how the bike progresses.

Is that any help at all ??

I've a Z, and I can say there are no surging problems at all. The ECU is different to the X/R and the Tenere has a much larger airbox - Yamaha reckon this is the reason.

However, the 2009 X/R's have a different ECU, and apparently there is no surging problem.

You mention Kev's fix, did you read this on www.XT660.com ?? I'm aware that lots of people have tried to resolve the surging problem, and Yamaha still won't admit there is a problem, curious why they've changed the ECU though.....

Despite having the same power plant as the X/R the Z is a different machine, and as such behaves differently too, also there is the added weight (especially when full of fuel), uprated suspension, better chassis, firmer swing arm, better brakes and more off-road bias wheels that mat well all contribute to how the bike progresses.

Is that any help at all ??

Thanks "Gas up lets go"for that reply, I'm totally new to this stuff so I guess I just add the reply on the bottom. Yes mate, that does help. The new model ECU on the 2009 XT660R is good info to check out with my dealer. This may be the Yamaha solution I'm after. I note The difference with the Tenere air box too which probably comes into the reckoning. Yes I did read "Kev's Fix" on XT.660.com. If any one else reading this has a later model XT660 I would be keen to know if your bike surges at low throttle openings to any degree.