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post #1 of 4 (permalink) Old 11-01-2012, 05:50 PM Thread Starter
Main Motorcycle: Sprint ST
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Rough Idle

So, just pulled the tank and airbox off to check the valves. one was at the high, screw it, put it back together, refilled oil. (i had it drained because of a Sprag clutch issue. Anyway, get the bike back together last night, fires right up. Ride it to work today (Brrrrr) and notice it just doesn't seem right at small throttle openings. Take it for a longer cruise on the way home (the direct route is like 3 miles) and notice two very interesting things. Bike doesn't quite want to idle, well, it was extremely surgey at idle, think bucking bronco, and it would not pop on decel... well it will but bearly and only at about 2k rpm, where it used to do it above 4k. Also, the fuel mileage on the instant gauge just doesn't quite seem right when under power. And when returning to idle it won't go to 99.9 like it usually does, and if anything it goes down. (less throttle, worse gas mileage. Sorry officer i had to keep the throttle wide open to be green)

I'm going to guess I didn't put something together right. There was a plug at about the back right of the engine on the wiring harness that didn't seem to go anywhere, and looked like it hadn't been connected to anything anyway, so that is still disconnected (it's in the same area as the fuel level sender connection) and I didn't mark which connection was on the fuel pump, so that's connected to the one closest to the fuel line. Nothing connected to the other location.

So... ideas? I know it is coming back apart just if i had an idea of where to look it would be nice.

btw, 2006 sprint st w/23k miles, and apparently a k&n airfilter.
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post #2 of 4 (permalink) Old 11-02-2012, 01:45 PM
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I have a 2000 so I'm sure its different. Sounds like you missed something when re-assembling. I would pick up a manual unless someone with an 05 or better chimes in with some help.

If I say something that can be taken two different ways, and the one way made you mad, then I meant the other one.
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post #3 of 4 (permalink) Old 11-02-2012, 02:29 PM
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My first guess from your description is that you disconnected the hose between the MAP sensor to the intake manifold. There are 3 short hoses coming off the top of the manifold. They join at a T-piece from where they run up the left side of the airbox to connect to the MAP sensor located on the outside of the airbox lid. That's where I would start.

It doesn't sound like electrical. Usual candidates are the MAP sensor and IAT sensor both fixed to the airbox. If either of these was left disconnected it should trigger the engine light. No mention in your post of a MIL light so I have to assume they're connected.

It's amazing how fast you can go when you take your time.
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post #4 of 4 (permalink) Old 11-06-2012, 07:27 PM Thread Starter
Main Motorcycle: Sprint ST
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No check engine light... however i'll take a look. I was traveling by car (boooooo) this weekend (it was cold... very cold) and haven't had a chance to get in there yet. That really does sound like something that might of happened.
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