Recent drop in engine idle

[Bixxer Bob]

Based on what you're saying, it sounds like it could be a vacuum leak.  The only hoses I've messed with are the hoses connected to the gas tank.  I had to disconnect all of them when I removed the tank to get to the air filter.  Maybe I need to go back & check connections.

It wouldn't hurt to do that, and while you're about it, check that the K&N oil hasn't gotten onto either of the sensors in the airbox.  I'd still be looking at the idle air valve pipework though....

Good luck

[RickV]

The idle has dropped to the point that the engine will stall out at a light if I don't feather the throddle.  My last tank of gas got me only 36 mpg.  The "prayer light" came on around 170 miles (4.7 gallons to fill up).  I've only been getting in the very low 40's since I bought this bike a few months back.  It even has a slightly taller rear sprocket, so it should be getting in the high 40's to low 50's...right?  The prayer light came on today at around 130 miles.  If it's correct & takes approx. 4.7 gallons to fill, that would be only about 28 mpg.

I took the air filter housing off tonight.  Pulled two of the three spark plugs.  They looked good, but showed indications of running slightly rich.  The idle control valve (the thing between TB #1 & #2 had a fair amount of crunge, so I took the cover off & wiped down the white sensor looking thing in the middle.  The only thing I found that didn't look good was the larger vent hose that plugs into the right rear bottom of the filter housing.  It was pinched closed about half way down.  Couldn't tell by looking at it how long it's been like that.  These bikes sure do have a lot of vent hoses (two in the air filter box, not counting the crank case vent line & three coming off the gas tank).  That's a lot of venting...LOL.  I got three 30-0 vacuum gauges.  I'll try to synch the throddle bodies tomorrow and replace the one pinched vent line.  If that doesn't do it, I guess it's off to the local Triumph dealer to plug into their diagnostic thingy.

[Bixxer Bob]

Was the crunge oil-related?  You're going to have to find out where that came from if it is because it'll only happen again.  If it's just dirt then just cleaning it out should be enough (although I'd still want to know how it got there if it was mine).

That plus the pinched pipe is going to throw your idle mixture way out - hence the stalling.  Hopefully, you're on your way to fixing it  :lol:

[RickV]

I think the crap on the sensor was just normal stuff that accumulates over a long period of time & miles.  It wasn't that much and not oily.  I went to the local Triumph dealer to pick up some brake pad & showed him the vent line.  He didn't think that particular vent line would cause an idle problem if pinched, but the others probably would.  I changed it anyway.  The TB's were in synch.  All the other hoses looked OK.  Made sure they weren't pinched when I put everything back together.  I put everything back together, but nothing changed.  Guess it's off to the Triumph dealer.

[RickV]

so... I take my Tiger in to the dealer for an inspection sticker.  While it's there, I have them check out the mapping and ask them to try to get the idle up.  Turns out, it was mapped for an after market muffler.  They remapped to the stock tune.  The previous owner must of had a sport pipe on, had it remapped, but replaced the stock muffler before selling the bike.  Now, it runs smoother in all rpms, especially under 3K.  It was probably running on the rich side.  Seems to idle much better... still a little on the low side, but it doesn't stall out at a red light.

I never seemed to get any better than 40 mpg (often less), even with a taller rear sprocket.  Sure hope this brings it up closer to 50 mpg.

RickV