OK, so my 06 gs500 was running funny, jumping up in RPMs and dying in the middle of riding, so i did a good carb clean on it and it still acted up. So, i rejetted it with 20/65/142.5, and put a lunchbox on it, and now it is even worse! it is making a hard popping noise that makes the whole carb jerk, and it is still jumping up RPMs on its own and dying out. Anybody had this problem?? I have been trying to get this bike running forever, maybe i will have to break down and take it to a shop. Any help would be greatly appreciated. Thanks!

Near-dead battery? Good idea to swap batteries. A battery dying can do some strange things to a bike.

back fire through carb sounds like timing....... Hope your not coming down with goats or something. That or loose valves. need more info, millage, accident history, any other mods, or tampering. Anything happen before this problem?

Back firing out the carbs is a symptom of leanness. How well does it run with the choke on?

Try messing with the jets some - until then put the factory intake back on.

Symptons steer towards carbs but check battery connections,engine earth.

the battery is new. it has 20/65/142.5 jets, lunchbox and one washer under the needle, stock exhaust... will it be ok to put the airbox back in with the bigger jets? the bike only has 1025 miles. can i adjust the valves and timing myself and do i need any special tools? thanks for all the replies!

my friend was riding my bike and he had put the fuel selector on PRI rather than ON and it was back firing. 

QuoteBack firing out the carbs is a symptom of leanness.

+1 

i agree with big rich.  although mine would backfire out the carbs becuase of a bent exhaust valve. 

I'll have to check the valves. When the choke is on, it revs really high the whole time. I'm guessing it might be the valves because i can't think of anything else. It only has 1025 miles on it. I will try to check the valves and then I have no clue!

Quote from: ray513 on September 15, 2010, 10:12:56 AM
the battery is new. it has 20/65/142.5 jets, lunchbox and one washer under the needle, stock exhaust... will it be ok to put the airbox back in with the bigger jets?

Just saw this - yes, you can put the stock intake on with bigger jets. A rich engine can run like crap, but a lean engine can take a crap.