Hi

I just baought a used Gsx-r 400 GK71F with som revving problems. When the bike is cold it revs out just fine but as sson as the bike is getting warm and i have ridden a couple of miles the bike struggles to past 10000 rpm, It runs fine up until 8k, if i twist full trhrottle it starts to blur as it not getting enough fuel and stops complete at 10k just like a rev limiter. If a turn the throttle just 1/3 of ful then it still struggles but can past 10k. I got a new CDI from the guy i bought the bike from and he told me that the CDI was programmable but i didn't get any equipment to program it. The CDI has a strange antenna on it and i couldn't find any information on the net about it. With the new cdi it revs much better it can past 10k but still struggles some times. The problem with the new cdi is that it blurs between 1k-3k the idle is fine and it starts fine but it feels like the bike getting to much fuel when i turn the throttle. So its hard to start from standing still it really needs to rev around 3k to take off from still. from 3k and up it runs just fine. The Cdi has the same part number as my old one so it should fit. The bike is registrered as 25 kw but the bricks are nott installed and the carbd been renovated.
http://postimg.org/image/sfymu9ztt/
any suggestions?

thanks

/Benny

The bike sounds too rich on top end fueling. Check what jets you have. std jets for totally std airbox or richer mains if the airbox has been cocked around with. If it std, maybe replace the air filter.
The stumbling off throttle could mean the air screws aren't right, or that you have too much advance on the 3rd party ecu. I would keep it std until you have it running correctly, then put the modded stuff back on, or you will spend months chasing it.
Nick.