Would like a little help, experience and guidance with the following issue involving my 2005 Yamaha 660R. It started with the machine sitting for about a year and the gas turning the carb to complete junk. Did the poor mans rebuild with a cheap kit and was unable to get the machine to maintain much past an idle. Seeing that the old carbs were pitted from letting gas sit as long as I did. I sprung and got a used carb from a well running machine. Bad diagnosis; same exact problem still. Then I went and put a new plug in and adjusted the valves for haha's. Was able to get the motor to run at idle perfectly but still unable to even get it to run 1/4 to 1/2 throttle goose without it backfiring through the muffler. The machine is bone stock and might have about 30 hours on it.
I really dont think it is a pilot jet setting issue because I had originally had toyed with that idea and with the new carb on I had the same exact issue without playing with the pilot adjustments. Is it possible that there is some sort of protection built into the circuit wiring that I may have disturbed at some point that might cause this run condition? I would appreciate any similar experiences along with what your resolution may have been. Or if you have some tips I would greatly appreciate whatever help you may be able to provide.
Thanks,
Matt

 

did you clean the new carb or just put it on

 

have you adjusted the e-clip??

 

check the slides on the carb. make sure the hoses are hooked up

 

Yes, I has did a re-build on the newer carb to satisfy my curiosity and the same exact thing still. Also tried different "jesus-clip" variations and no difference either. Thought there may have been an issue with the intake boots but they are fine also. The only thing that seemed to somewhat make it idle perfectly was the valve adjustment because I had backfire in the airbox originally as well. I know these dual carbs are tempermental, but what a pain! The pilot adj on the bottom of the carbs; what would be the rule of thumb if I backed them out and ran them back in? 3 complete turns from bottom out for stock setting?
Pulled the carbs off again tonight; went through them and made sure they were seated properly into intake boots, wiring is secure and still same exact thing. WIll look into valve adjs again and the remote possibility of a timing issue.....

 

check the parking brake

 

DOLLAR BILLZ- YOU WERE RIGHT ON THE MONEY. THANK YOU. I WENT AND WAS TWEAKING ON THOSE DAMN CARBS AGAIN TONIGHT AND I GOT SO FED UP WITH THE RESULTS. AND WHEN I WENT TO SHUT THE KEY, I SAID LET ME SEE ABOUT THIS PARKING BRAKE SWITCH, AND SHE FIRED RIGHT OFF AFTER DISCONNECTING IT. I DIDNT REALIZE THAT THERE WAS A MICROSWITCH BUILT INTO THE CIRCUIT OF THAT BIKE TO DO SOMETHING LIKE THAT. I WAS STARTING TO THINK SECONDARY IGNITION BREAK UP- BUT YOU CAME THROUGH AND FROM NOW ON I WILL BE THINKING OUTSIDE THE BOX.
THANKS AGAIN.....