2002 katana 600 bad rev when first started

[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

Read more: https://forums.motorcyclecruiser.com/70/8913540/tech-tips/katana-600-long-warm-up/index.html#ixzz1ZOpp4HKB
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bob adam