Possible Vacuum leak

[onetuford]

I took my air box apart to get after a dirty/sticky throttle. Put it back together, reset TPS, and rode it. It was running like a bike with a vacuum leak, surging at idle, and not idling down. This wasn't happening before. Found the main vacuum leak being the stack not set in the TB properly. I did notice a nipple on the TB that didn't have a hose or cap on it. Checking the manual for a while I see its for emission equipped bikes. Non evap can bikes should have this capped, right?

 

[user_deleted]

yep.

airbox to TB rubber boot if not connected and clamped properly to the TB causes precisely what you described.

 

[onetuford]

I figured as much but wanted to make sure there wasn't a super sneaky vacuum line in there someplace. Thanks a heap for the reply lunatic! Much appreciated!

 

[user_deleted]

I figured as but wanted to make sure there wasn't a super sneaky vacuum line in there someplace. Thanks a heap for the reply lunatic! Much appreciated!

always my pleasure. 2 quick notes of interest: that vacuum fitting is 3/16th inch or very close to that. a rubber nipple from auto parts store works best. put a very small dab of rubber cement or 3M trim/vinyl adhesive on it...then slide on...then wait to cure before starting. in some instances a very strong backfire up thru the TB will blow off the pipe nipple if not secured as mentioned. on the rubber boot you must press it down firmly onto the top of the TB till you feel it "engage" in its groove. you'll feel it when it does. then install the large spring clamp. that is the only method that keeps it secured forever. spray the upper section of it with something like kano kroil or silicone spray then install airbox base plate....then with long thin flat blade screwdriver work the lip of the air boot around and into the base plate. PRIOR TO DOING THIS be absolutely certain to plug the IAT sensor into the harness. it can't be done after boot connected to base plate. it is split lip design and must be seated correctly into the base plate. then fasten plate to frame with 4 torx.