Hi,

I just changed spark plugs in my K100 -84 and as i took a look at them after one day of running they all looked like this:
 

I'm fairly new to injection bikes and new to my k100 so I'm not sure which screw I need to adjust to adjust the mixture. I'm used to simple carburetors  

Any pro tips? 

Best regards,
Jens

What plugs are you using? They do look very white.

Looks like an NGK D8EA which, if I remember correctly, is one step colder than the specified plug. 

Are all the plugs like that?  Most likely you have a weak fuel delivery caused by low pressure from a bad regulator, weak pump, or plugged fuel filter.  It's possible, but unlikely that the ignition timing with the Hall Sensors is way off as well.

Check all those items, and if the problem persists, it may be necessary to go into the MAF sensor and possibly the engine control module.

How is the engine running?  I would expect it to be pinging a lot, and having problems coming off idle if it even idles at all.  No power at high rpms.

If it is only on one cylinder, you probably have a massive air leak at the throttle body rubber bushings.

could I add,    it just could be a sticky fuel injector (that needs a good service ).... if the others are  a different colour that would confirm that fuel delivery is ok
we have seen this kind of thing before
but not to discount leaking rubbers from head to throttle bodies ...or even injector o rings


hope that helps

Not to get political or anything but it's obviously Swedish white privilege.

(I'm about 60% Swedish.)

Point-Seven-five wrote:Looks like an NGK D8EA which, if I remember correctly, is one step colder than the specified plug. 

Are all the plugs like that?  Most likely you have a weak fuel delivery caused by low pressure from a bad regulator, weak pump, or plugged fuel filter.  It's possible, but unlikely that the ignition timing with the Hall Sensors is way off as well.

Check all those items, and if the problem persists, it may be necessary to go into the MAF sensor and possibly the engine control module.

How is the engine running?  I would expect it to be pinging a lot, and having problems coming off idle if it even idles at all.  No power at high rpms.

If it is only on one cylinder, you probably have a massive air leak at the throttle body rubber bushings.

Yes, they are NGK D8EA. They came with the bike so I put them in brand new. 

All plugs are the same. I have a new filter and will do a change later this week. Might as well look at the pump then.   

The engine is running OK but with hesitation or even dying sometimes if I pull full gas right off idle. But it idles kind of OK.  

I have just stripped the bike down and built it back up again with new rubber hoses so it shouldn't be leaking air.

yes check the pump output pressure on the fuel rail , which will indicate the pressure regulator operation ''  with out vacuum line attached ...just under 3 bar ...attached  pulsing down to 2.5bar  or something like that

today was chasing a similar issue with the engine running seems like water in fuel ...turns out the pump was dying , drawing 5 + amps after just a minute of operation (unloaded )   the tank connector was showing melted plastic around the connection ...fuel pump replaced ...testing tomorrow

Put D7EAs in and give it a 50km run then see what the plugs are like.

I used mostly D8EA as they are widely available locally. Then got D7EA and did not notice any difference at all. Reminded me of my two strokes and I always ran a grade colder than recommended and no issues. I still do lots of long high speed runs and thus tend to stay a grade colder.

Hassnen wrote:. . . they are NGK D8EA. They came with the bike so I put them in brand new.

Do the ends of these spark plugs have the same type of wire connections as the spark plugs they replaced? They should. If they didn't, that's ikely the source of the problem. The HT leads must fit firmly.

Did you check their electrode gaps before you installed them?