02 katana bad rev when first startd

[carbone987]

i have a 02 katana that has a bad rev when you first start it it take's about 15 minute's in neutral around 10 if i drive it now the problem is that when i rev it up it gets stuck around 3500 rpm for the first 15 minutes and it just keep's bouncing off that rpm eventually it will break thew and red line but when you let off it it will do it again after around 10 15 minute's it revs up fine no problem's after that be side's it back fire's because it has a after market slip on D&D muffler with stock jets. i thought the carb's had to be cleaned so i cleaned them they were pretty dam clean when i opened it up i cleaned out the jets anyway put it back together and there was no improvement i don't think the exhaust would make it do that but i don't know any help would be awesome thanks its not stuck at 3500 it ideals fine when i first start it up i choke it for around 30 seconds at about 2500 then turn off the choke ideals around 1200 sounds pretty good but as soon as i rev it up it starts going up and just stops at 3500 revs a little down trys to go up again and just stops there again it will do this over and over again but after around 15 minutes it revs up perfect heres a video of it you can see how it gets stuck its like that for the first 15 minutes of rideing https://www.youtube.com/watch?v=5DKq0RDSokw&feature=player_embedded
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bob adam

[pits]

Sorry I ran out of breath halfway through, oh and we have this place on here, it is called the workshop, it is where you post your massive chunk of text without any commas or paragraphs, this is so the speed readers who can read a chunk of text without breathing can understand you......Wait that isn't right, sorry the workshop is a place where you can post about the problems with your bike, and someone will answer providing it is actually readable.

From your video, looks like a flat spot in the carbs, when was the last time they were set up? Is it a carb bike? As most bikes do have a flat spot for emissions, can you feel any slack or sticking in the throttle or choke cables?
When you took the carbs apart did everything move freely?
When was the last time the bike was set up?
Have you checked the plugs?
Have you checked for any vacuum leaks?
Have you checked to see whether your commas have fallen in the carb and making it stick?

For those who also gave up reading the unpunctuated block of text.
Bike warms up fine on choke
Choke comes off
Bike has flat spot around 3,500