I have a 2000 yzf 600 it has dynojet kit stage1 and d&d exhaust. It idols good, but after 2000 rpm's to 4000 rpm's, it cuts out and kinda flutters. After that it runs great up to 13000 rpm's.

This should help.http://www.dynojet.com/pdf/1145.pdf

HI A DYNOJET KIT INCLUDES MORE THAN JUST MAIN JETS, AIR CORRECTORS, SLIDE NEEDLES, AND IN SOME CASES NEW SLIDE SPRINGS ARE INCLUDED, SLIDE LIFT HOLES ARE ALSO DRILLED OUT TO GIVE QUICKER THROTTLE RESPONSE, AS DAFT AS IT MAY SEEM YOU NEW MAIN JETS IN MOST CASES WILL BE SMALLER THAN THE ORIGINAL JETS, IF YOU ARE THINKING YOUR BIKE HAS BEEN DYNOJETED BUT ARE NOT SURE CONTACK DYNOJET UK FOR HELP, HOPE THIS IS OF USE FOR YOU,
http://www.dynojet.co.uk/jetkits/index.htm

This was happening to my Yamaha 1996
yzf 750r I found my Ignition swich was to blame I slow and gentle pulled it apart and found a broken part inside and fixed it,

just check your wires on Ignition switch first.

The Yammy 600 run at high RPM. Also depends on rear tire size

Pulsar 150 CC
Power 20 hp (15 kW) @ 8500 rpm
Torque 19.12 N·m (14.10 lb·ft) @ 6500 rpm
5-Gears
Power (bhp) 14
she won CNBC-TV18 Autocar Auto Awards—Bike of the Year in 2007.
the stats are nice for a small bike, id suggest jetting the bike, it will not be difficult and is extremely effective, checkout dynojet kits just go to Google type in dynojet kit see if you can contact them and ask about a kit for your make and model. they might be able to figureout the kit that will work with your engines displacement 150 cc. id throw a aftermarket exhaust system on their, this will lower backpreashure and restrictions of exhust gasses, as well as remove the limatations they put on eom pipes.

Sounds like you have either a carb with a sticky slide. Pull air box and look down carb throats while twisting throttle (assuming the bike is not EFI)

If you have installed the Dynojet kit's carburetor needles take them off and use the stock ones.
Dynojet's needles are for track use only and the don't work properly under 4000rpm.

Hello,
This is an old thread but we found the answer after checking if a part no was correct....
The box is an O2 controller for a Dynojet Power Commander kit.
It is used to bypass the sensor that fits into the exhaust to allow full ECU performance/fuel modifying.
Part no 66391201 is also the same compatable part as 76125003 and is used in certain other Dynojet kits. (Daytona 600)
Hope this may help any other Triumph owners with the same question. :)

If you are not running an open or free flowing exhaust go back to the stock size jets but use the DynoJet parts instead of the stock.
DJ jets tend to run bigger than oem jets