K11 Owners Group

Milton · Posted: Tue May 20, 2008 1:28 pm Post subject: What did I do?

I screwed up my gas mileage by 10mpg and I want it back. Embarassed

I finished up a major repair/maintenance overhaul of my bike about 3 weeks ago. I replaced the Bosch plugs (don't know the number off hand but they were different looking plugs. Center electrode with 2 ground electrodes coming up on either side of the center electrode) with Autolite 4163. Also the throttle body linkage had obviously been mucked with as there was no blue paint anywhere to be seen on any adjusting screw lock nut. So I built my own man-o-meter and have set the balance at least 4 different times in the last several weeks. I don't think the bodies could get any closer outside of a flow bench.

Before I started mucking with the throttle bodies the "Throttle Position Sensor" had been pretty much centered within its locking bolts. I had never checked it with a multimeter for its voltage before the overhaul so I don't know it's before I screwed it up voltage setting.

When I set the TPS up with my multimeter (analog) to 375 millivolts I twisted the TPS counter clockwise to the limits of the locking bolts (couldn't turn it any further) but it did get to 375. If I twist the throttle (no more than 1/8 turn) the needle on my multimeter jumps off the scale and I have to go to the next setting which gives 1.250 volts for max throttle open (1.25 volts from 1/8 -1/4 turn to full open). I read somewhere (k-bikes.com I think) that the TPS should give a smooth response on the multimeter from 375 to no more than 500 millivolts at max throttle open, with no spikes, as the throttle is opened. I've not seen any other mention of this type of test on other boards. Is my TPS junk?

The Motronic brain does not show any error codes, it thinks everything is fine.

I can certainly smell unburned fuel in the exhaust at idle. Bike runs strong just poor gas mileage.

Thanks for any advice,

Milton S.
_________________
Jethro Tull: Thick as a Brick!

1992 K100RS 48K. Dead for now.
1998 Triumph Tiger 43K->56K. Doin it in the dirt.
1978 Honda CB400T 32.5K. For my boys.

bmwmick · Posted: Wed May 21, 2008 3:02 pm Post subject:

Milton,
Did you do the TPS test here?
http://k11og.org/forum/viewtopic.php?t=2110 I would put it back to center on the slots and use the diagnostic to get it close.

I'd also suggest you borrow a good digital voltmeter and you will find it's WAY too rich. I don't trust analog meter at that low of a voltage.

Mick
_________________
Mick McKinnon
KOG#175
'93 K1100LT, '96 R1100RT, '84 R100RS, 2010 Kawasaki C-14
Tucson, AZ

Scott_Anderson · Posted: Wed May 21, 2008 7:01 pm Post subject:

Milton, I just did almost the same thing you did, new plugs (autolite 4163's), sync the T.B.'s and set the tps. I also cleaned the airfilter and plugged an errant vac leak. My mileage went up 10mpg after all this.
I set my T.B. balance with the brass vac screws, not the butterfly ones.
My air filter was nasty couldn't see light through it when I started but I could when I was done.

Ride safe

Scott

Milton · Posted: Tue May 27, 2008 7:57 pm Post subject:

bmwmick · Posted: Tue May 27, 2008 8:04 pm Post subject:

Yes,
Rotating the TPS clockwise lowers the voltage and leans the starting point at idle. Does the TPS test now work correctly?

Mick
_________________
Mick McKinnon
KOG#175
'93 K1100LT, '96 R1100RT, '84 R100RS, 2010 Kawasaki C-14
Tucson, AZ

Milton · Posted: Fri May 30, 2008 12:23 am Post subject:

bmwmick · Posted: Fri May 30, 2008 8:22 am Post subject:

Great! Glad you got it right.

That TPS test is sort of a 'ballpark' test but it does validate your meter somewhat. Smile

Mick
_________________
Mick McKinnon
KOG#175
'93 K1100LT, '96 R1100RT, '84 R100RS, 2010 Kawasaki C-14
Tucson, AZ

hirschhs · Posted: Fri May 30, 2008 10:37 am Post subject:

I just read through this whole thread without understanding a word!!
Shocked

_________________
Cheers, Steve H _______________________________________
K-less in Bucks
2001 ST1100A

1994 Yamaha 600 Diversion 'Hers'
2006 Kawasaki Z750s 'Hers'

bmwmick · Posted: Fri May 30, 2008 11:12 am Post subject:

Steve,
Sometimes my head hurts. Smile

All this trivia is taking up valuable brain cells.

Mick
_________________
Mick McKinnon
KOG#175
'93 K1100LT, '96 R1100RT, '84 R100RS, 2010 Kawasaki C-14
Tucson, AZ

Off the grid · Posted: Fri May 30, 2008 12:02 pm Post subject:

hirschhs · Posted: Fri May 30, 2008 1:49 pm Post subject:

but don't you just love it when they talk technical.. Very Happy

Ohm.... watt? Very Happy

_________________
Cheers, Steve H _______________________________________
K-less in Bucks
2001 ST1100A

1994 Yamaha 600 Diversion 'Hers'
2006 Kawasaki Z750s 'Hers'

bmwmick · Posted: Fri May 30, 2008 4:08 pm Post subject:

Damn, I feel used. Smile

_________________
Mick McKinnon
KOG#175
'93 K1100LT, '96 R1100RT, '84 R100RS, 2010 Kawasaki C-14
Tucson, AZ

Milton · Posted: Fri May 30, 2008 6:49 pm Post subject:

I love wrenching, always have. It's so nice to have such a knowledgeable bunch of people to help with problems.

I also love wenching. My wife complains that I should spend more time twiddling with her sensors instead of the K's!! Laughing

_________________
Jethro Tull: Thick as a Brick!

1992 K100RS 48K. Dead for now.
1998 Triumph Tiger 43K->56K. Doin it in the dirt.
1978 Honda CB400T 32.5K. For my boys.