Im sure this will be a broken record for some of you and im sorry but this is kinda aggravating.. moving on

I bought my 05' Suzuki GS500F Motorcycle last winter and it needed the frame painted it looked pretty ugly unfortunately as well as a new clutch basket and some minor sprocket work. after this was done (sprockets and clutch) the bike ran fine no issue at all. This winter i disassembled the bike to bare frame so that i could get it powder coated (looks very nice  ). i reassembled it as well and everything went pretty smooth, yesterday we had 60 degree weather so i decided to put some fuel in and start it. it started right up i had to tweak the
idle screw a bit but nothing major. then i installed my new EXHT (DELKEVIC COMPLETE STAINLESS STEEL EXHAUST SYSTEM
And DS70 9" Carbon Fiber Oval Muffler For Suzuki GS500F (2003-2009) ) after this i did the clean air mod removing the PAIR Valve system. i went to take it for a spin and it was great until you hit about 6-8K rpm then it wont go any higher it jerks like it wants to go but just wont! i will attach a small video of what its doing and maybe someone can shed some light on this! idle is fine and take off is fine it just cannot get passed that 6-8K RPM i will be taking a better video while riding the bike shortly it shows the issue a lot better.

IIRC that's about the RPM the needle should be lifting out of the main jet.  If that's not happening there could be an issue with the diaphragms and/or there could be vacuum loss.
I
'm not too familiar with the PAIR system but logic says whatever you did there would be the culprit, have you tried putting it back together?
Changing the whole exhaust should be followed by a rejet, but a lack of rejetting wouldn't cause such a dramatic issue.

Someone else will know more about this than I do, they're sure to be along shortly.

Quote from: Watcher on March 01, 2018, 01:22:45 AM
IIRC that's about the RPM the needle should be lifting out of the main jet.  If that's not happening there could be an issue with the diaphragms and/or there could be vacuum loss.
I
'm not too familiar with the PAIR system but logic says whatever you did there would be the culprit, have you tried putting it back together?
Changing the whole exhaust should be followed by a rejet, but a lack of rejetting wouldn't cause such a dramatic issue.

Someone else will know more about this than I do, they're sure to be along shortly.

thanks for the reply! the website says not jetting required but if need be i have no prob jetting the carbs but i would have to figure out what stage. also the pair system recycles "unburnt fuel" back into the carbs instead of dumping it into the air. only installed to make the EPA happy

Almost definitely you have somehow caused a vacuum leak or completely open vacuum port that is causing the slides not to come up.

The fact that you said "stage" in reference to jetting tells me you might have been considering some off-the-shelf "kit" for rejetting such as from Dynojet. In a word: don't.

In the long run you may find you would like to +1 the pilot jet and main jet, but it should run fine if a little lean without any jetting changes. The exhaust swap hasn't changed anything that necessitates a change in jetting.

There are plenty of posts on this forum about removing the PAIR system, I suggest you study those and retrace your steps and I bet you find some hole is left unplugged. In any case you can verify what's happening by looking into the throat of the carbs (air box off) while the engine is running, when you open the throttle you should see the slides move up. If they are not moving up, the needle is staying down in the main jet and that's your problem. It's vacuum that pulls the slides up by way of the diaphragms under the tops of the carbs. It will then just require debugging to determine why the diaphragm-slide action is not working, which is usually either a damaged diaphragm (you didn't spray carb cleaner in the carbs, did you?), some vacuum port left uncapped or unhooked from the vacuum line, or another large vacuum leak somewhere (intake boot o-rings, some other o-rings left out/missing, etc.).

This isn't the only potential cause of your issue but it's far and away the most likely, and easiest to check. Removing the PAIR system is your main clue.

I just blocked the white valves off by connecting them together, and blocked on end of the T piece and left the rest to go to the vacuum petcock. the air filter at the top doesn't suck anything in because 1. it's blocked off and 2. the valves can't get vacuum