kawasaki air flow problems!

[Buju #72]

Hi guys. I'm having some real problems with my 2002 636. It revs (red lines at low speeds) absolutely fine but when i get to around 125mph it just bogs out. I did cadwell park on it a month ago without any air flow scoops fitted (i'd just bought it n it didn't have any fitted at the time). Super fast around the bends but soon as i got onto long straights and tucked behind the screen, it just basically cut out after 110mph, then re-engaged when dropped bellow 100. Anyway, bought some scoops from an earlier model. They didn't fit properly so i took the secondary small air box off (if your familiar with this model you'll know what i mean) and fitted them using good old gaffer tape.  So the air is definately getting in there now but at mallory yesterday exactly the same thing was happening!!  What was interesting was when the wind was behind me, it appeared fine, but when i was going into the wind (and it was windy!) it was even worse! The problem looks obvious, but before i waste anymore money, is it definately air flow problems?? Seems wierd how with no air tubes, and with air tubes (although not the correct ones), it does exactly the same thing!!
Thanx guys and sorry for the long windded post...

[oneal]

First things I'd look at would be the spark plugs, then the air and fuel filters.  Any idea when these were last changed?  Are you running a stock exhaust?

Good luck - problems like this can be frustrating

[Buju #72]

The plugs n filters must be fine cos it revs perfectly! (at low speeds.) It's only 125mph+ (its a trackbike mind coppers and law abiding citizens!!) However, the exhaust is VERY different. It's had an underseat pipe fitted (looks mint and sounds like a jet fighter!!). This is what I thought at first, but again it revs at low speeds so surely can't be a wrong jet (carb) problem!?!? Tell me different.....

P.S Appreciate your help mate!

[oneal]

Fuel demand at high speed (and wide open) is much greater than at low speed.  Still think it would be worth checking - fuel filters are relatively cheap.  Carbs could also be the problem, but those are a black art and I leave that stuff to the pros.   

[Buju #72]

hmmmm Interesting. I'll have a delv and let you know....

Thanks again mate!