Thanks for the reply but have already done that   

Hi All,
I have a problem with vibrations between  4k and 5900 rpm...yes that accurate 

Any ideas what is wrong ? It was runnng fine until recently and I haven't changed or done anything to it. Vibrations are coming through the bars, footrests and frame / tank. The bike has no fairing and the indicators are non-standard and the carbs were balanced recently. The bar end weights are on and to improve the footrests I bolted on some steel bits at the ends...I thought that if it works with handlebars it was worth a try. Seems strange that at 5900 rpm and above it is like someone is switching off the vibes so that there are no vibrations at all.

Any ideas where to look?

Here we go, this link takes us to the part I was suggesting. Even the position of 6th gear is easy to see..and drill 
I know it's a different bike but same part number I believe.

http://www.ebay.co.uk/itm/YAMAHA-YZF-600R-THUNDERCAT-1996-2004-NEUTRAL-SENSOR-1AE-82540-00-00-/171954104838

Heidenau K60 tyres 

Thanks for all the replies everyone...you've cleared that up nicely 

Centre stand is fine.

The handlebars have the weights attached and an additional 25mm length of 20mm rebar added on (with hole in for fixing bolt) for good measure.

Might try filling the bars with lead shot and silicon sealant or sand, just to make sure  Would fixing some heavy weights to the outer edge of the footpegs help at all ?

I had a go on a fuel injected Triumph TT600 recently...and it was about the same as mine anyway, so maybe I'm expecting too much. It's just that previous bikes have been as smooth as silk all the way up the rev range even with no handlebar end weights !
 

Mine's a single seat with no pillion footpegs ...therefore no missus on the back  ..so no problem there!!

Any other thoughts/suggestions/experiences/opinions anyone ? These vibrations are making the riding experience intolerable 

Good point about balancing the carbs at idle. I followed the guide on the forum and it states that the process should be done at tickover. My previous bike, a gsx750f used to be balanced at 1800rpm.

I can understand that throttle bodies can be balanced more accurately and result in a smoother engine but I'm sure mine is as good as it will get....at tickover anyway 

One other thing, it has an aftermarket link pipe and silencer and the centrestand pushes against it when it is up. I'm wondering if this is causing some of the vibtation as the right peg vibes worse than the left !!

Also, there are very slight vibes in the handlebars but I read somewhere that as mine are a little bit bent, that is all it needs to set of vibrations in the bars 

I've just balanced my carbs in order to cure vibrations in the footrests and seat. The carbs needed minor adjustment but this hasn't improved the vibration problem.

The vibrations are only felt over about 3500 rpm, under this it is more or less vibe free. Also during acceleration there are no vibrations throughout the rev range. The large washer has already been fitted behind the exhaust mounting bolt and I've put a soft rubber washer underneath the front tank bolt which has stopped tank vibes.

I used the two jam jars with fluid method to balance the carbs and this was done with the engine at tickover speed. However, whenever the throttle was blipped, to ensure an accurate balance, the fluid levels in the jars changed quickly. Does this mean that at higher revs the carbs are out of balance ? Or is something else wrong, causing the vibes at higher revs ?

Your thoughts would be appreciated

Oh dear.....I've only got jam jars.

On previous i4 bikes I've successfully used a DIY balancing tool consisting of two jam jars containing light coloured oil with plastic tubing etc.

Will my Fazer balance okay with this set-up or will I have to fork out for a proper tool !!

Here's a recent pic which I've already posted on other threads...

120/90 on front of mine