Running rich

[Bill]

My 88 K100 is running rich as evidenced by a carboned exhaust and complaints of those behind saying it stinks of unburnt fuel.  As it is my first K and prior experience was a carburetted  750 I can't say performance is less than I expect.  Runs smooth, pulls strong with no hesitation, and idles at 1000. 

So..... where do I start ?  I am going to verify the fuel pressure regulator first.
Then the air filter and all components.

My thinking is:
1. Set TB bypass air at 1.5 turns.
2. Ensure all butterflies are closed.
3. Set AFM bypass ?
4. Sync ? 
5. Repeat to get 950 idle ?

Or is there a complete procedure I can follow ?

Thanks for any leads / direction .

[johnny]

greetings bill...

id make sure my nocornethyl is new... id make sure my sparkplugs are new... id make sure my fuel filter is new... then id disco my jetonic connector and clean all that out... then i would do a full on hot with fan running throttle sync with a carbtune or similar... then i would put a full bottle of techron in there... then id go bust out 100 miles...

if still whack id fill it up with nocornethyl and get a full bottle of seafaom in there... then is bist out 100 miles... top it off with nocornethyl and see how it goes...

if still whack id go full bottle of techron and full bottle of seafoam and but out 200 miles...

if still whack id park it and getts another one while waiting on inge to come to usa on holiday for a valve job amgunst other unnecessary stuff...

j o

[TimTyler]

I'd warm up the engine and then depress the green start button for a couple of seconds. If engine RPM's increase a little your fuel mixture is probably good.

If anything else happens you need to adjust the bypass screw on the airflow meter. Use a short 5mm hex key and follow these instructions http://skylands.ibmwr.org/tom/tech/co-setting.html

The "butterfly bypass screws" are the four brass screws; one for each cylinder.

[rbm]

Richness in the mixture across the range is probably temperature sensor.  Check the connection to the sensor and follow the procedure to measure its resistance.  Replace if defective.

[Bill]

Thanks for that rbm.  As one thing I've noticed although weather has not been warm, the temp gauge never gets to half scale regardless of how hard I run.  Thermostat stuck open ?  or running rich keeps it cool ? ....  Running lean I would expect higher engine temps as a side effect. As I am replacing the fairing and adding tip over bars this weekend I'll be able to check a lot 'under the hood'. 

[rbm]

The temp sensor for an optional temp gauge is totally different than the sensor for the ECU/temp relay.  Failure of one will not affect the other.  If the temp gauge is not rising past halfway, then I can't offer an opinion; sorry.  If the fan is not coming on despite the cool temps we've been having here in the GTA, then that is controlled by the temp sensor which is under suspicion.  You could test the fan's operation in addition to testing the temp sensor, if you suspect that the fan might be acting up as well.  If you trust the fan circuit to be working, then suspicion continues to point to the temp sensor in the stand pipe on the left side of the engine block behind the radiator. 

BTW I've been driving my K75 in stop-go traffic this week and the fan is coming on regularly for me.  So, it's not a function of the cool ambient temps we're having.

You should be able to get at the temp sensor to replace it without removing the radiator or draining the cooling system.  I've done it.  You need a hose clamp, like a set of vice grips with long thin jaws, to squeeze the return hose.  Then you should be able to access the temp sensor by removing the air filter box.  It's tight in there but just doable.

[riots100]

I had a similar issue with the engine running rich.  Replacing the temperature sensor fixed the problem.  It also fixed the problem of the fan never coming on no matter how long the machine was idling...

[Bill]

Set about removing my LT fairing so I could check various components for my rich running issue and then install the like new one from the parts bike ..... Discovered the following:
     1. A main fairing bracket compromised by rust.
     2.  Seized cooling fan.
     3.  How tightly packed everything is ....

My parts bike has:
        a free wheeling fan   :2thumbup:
        a good fairing bracket.

Working theory on 'running rich' is that the PO removed thermostat to compensate for the dead fan, causing the engine to run cold.  The FICU then keeps the mix rich to compensate.  As I have to drain coolant to re and re the fan I can check for the thermostat and also get at the temp sender to check values.

First time having the K this open so I can now get familiar with where everything is ....... maybe I'll find that elusive 'Altitude ' plug  :yes

[beemrdon]

 :2thumbup:

[F14CRAZY]

http://www.motobrick.com/index.php/topic,5038.msg53644.html#msg53644

[Bill]

While I had the engine and cooling system exposed :
     1. Checked the temp sensor resistance values [both sides] against the sensor on the parts bike and all were of similar value .... about 4k ohms.  Cocluded cold running cause not there.
     2.  Replaced left radiator hose as it had been damaged by the rusted out and failing fairing bracket.
     3. Swapped the rad, fan and thermostat with spare from parts bike.
     4. Ran the bike briefly checking for leaks .... okay

Won't be able to any more until the new fairing and electric windscreen are fitted so the puzzle remains ..... :dunno

[riots100]

The key to checking the temperature sensor is to see if the values change with a corresponding change in temperature.  You can still have a defective sensor even it is reading correct values when the bike is cold.

[Bill]

Agreed,  but now I have the first part of that measurement done.  At 7 C ambient all 4 resistances were similar is encouraging.  On the positive side I got familiar with where stuff is and where to measure in the harness.