spending too much gass

i dont know why but i think that my bike is spending to much gass. it is spending up to 9-10 liters in 100 km can anyone tell me what the problem might be .
can it be maybe the akrapovic exhaust not installd properly ?

Thats sickening
Are you sure there isn't a hole in your gas tank?

But seriously, must be running extremely rich for something like that to happen. Check your plugs for black residue, maybe someone botched your rejet.

[Biker Biggles]

Chokes stuck.Check the cables and the plungers on the carbs as these often sieze causing a very rich mixture and poor running/fuel consumption.

Assuming that your bike is a curvy, your carbs may need synchronizing. Check that you have no air leaks in the exhaust system. Check the carbs are fitted correctly without air leaks. You may need to change your main jets to match your exhaust.

Assuming that your bike is a pointy, your throttle bodies may need synchronizing and again check the exhaust system for air leaks.

Check your plugs. They will tell you how efficient your bike is running.

[Viney]

I usualy get around 10 mile per litre

That's pretty much what I've always been getting as an overall average, and mines a K6. (Sometimes more, rarely less)
I blame it on my heady right hand though

Edit: After reading your post a bit more carefully... Is your Akrapovic exhaust an open can? (No baffle) In which case if you haven't had the ecu altered (On a dyno) to adjust the air/fuel mixture then it may be throwing in a bit too much fuel.
It was the same when I first put my Renegages on as they're open... before I got the ecu altered it was throwing out loads of excess fuel into the exhaust. (Did make some nice flames though!)

Is the performance still good?

[northwind]

Even though the exhaust should make you lean, that can make the bike run inefficiently, meaning you use more fuel for the same result. But I'd be surprised if that's all there is to it.

Is this something that's developed, or something that it's always done? Riding style has a huge amount to it, I can get 160 miles to a tank or often under 100, depends entirely on how I'm riding.

Checking plugs won't necessarily let you know what's happening as there are loads of cleaning additives in modern fuel.

guys you can see the photos of my bike. i can not undrestand all the terms that you are using
like "carbs need syncroizing"
i just got the bike 2 weeks ago.
anyway thenx