Bad vacuum line...would it cause this? Please help!

[Woody72]

My bike has been running like complete crap lately. I've been getting a lot of decel popping and gargling, and intermittent backfires. I pulled the plugs and the front one looks so so, but the back one is fouled pretty bad. I was getting ready to fork out another $270 to get it tuned, but while i was tinkering today, I noticed that the vacuum line on my hypercharger dry rotted and cam off. Could the lack of vacuum cause it to run like this? Any help would be much appreciated!

[DR_DEUCE]

It will cause it to run as you stated. Popping on deceleration. And it will raise the idle if carbed. It will not cause the rear plug to foul. Replace the line and swap front plug with rear.

[csoday]

It could be the vacume line and that's a cheap fix to try first. You may also have an exhaust leak or bad plug wire. If the bike was tuned and running fine, there is no need to re-tune unless you have changed engine components. EFI does not lose it's map unless the ECM is completely fried. You would know that.

[Woody72]

Thanks for the reassurance. I installed a new vacuum line, and changed the plugs. The RPM dropped by about 300 or so with the vacuum line hooked up and it seems to have a little pep back.