Jetting and spark plug experts please help
 

Hi all, I'd appreciate some help with this. I Recently purchased a brand new 2014 xc300 and ran the motor in over a few hours mainly going from low to 3/4 revs with the occasional wot, then checked the plug and it appeared to be on the rich side (bit oily and darker sort of a tan). I put a fresh plug in yesterday and rode sand dunes giving it everything for an hour then checked the plug. See pic attached.

Im no expert but is it looking too lean? If so where should I start?

Thanks in advance for any advice.

Dangerously lean.Did it spew a lot of radiator fluid? Have a look at your radiator level. Probably needs 2 sizes bigger on your main jet but post up what jets & needle you currently have,elevation you ride at & temperature.Also what oil ratio are you running?

No radiator fluid lost - its still full. There was a burning smell when I was riding it though, I was thinking maybe it was just because it was new.

I ride at sea level, temperature is about 15 degrees Celsius at the moment

Not sure about jetting settings yet, it will be set at whatever it was set at from factory I guess, but I will open it up tomorrow and report back.

The strange thing is that the orginal plug looked almost too rich, what changed?

Also the silencer is leaking out a lot of unburnt oil - seems a weird thing to happen since the plug appears so lean?

Running 50:1

Im a total novice when it comes to this stuff so you're probably going to get asked a bunch of rooky questions as try to figure this jetting stuff out.

May not have badly over heated then.
Open the carb & get the sizes,they can vary a bit from bike to bike.
With a bit of jiggering you can rotate the carb & remove the needle & jets.
Difference would have been riding up to half throttle where it sounds too rich & then riding in sand with a lot of full throttle where it is very lean jetted.
Just check also that the rubber boots either side of the carb haven't come loose & started sucking in more air?

Do you think I would've done any damage with it running lean?

Also do you mean remove the jets and needles with out removing the carb from the bike? Ive never opened up a carb before so not really sure what im doing.

The rubber boots appear to be on properly. But I noticed a bolt had fully come out (see photo attached, the bolt above the chain) I didnt lose it because it couldnt get past the chain. Couldve that casued use any air leaks or cause any other problems?

If your running in deep sand, I would go for a larger main jet. (better safe then sorry)
I think a good starting point would be 42 pilot NEDW needle clip #3 180 main.
When jetting for deep sand I go one step larger on the main until it starts to sputter at wot then go down one size.
Also be sure you are using the correct plug heat range (br8es)

Running lean in deep sand for long periods can do damage but it's still running.Tough engines.
Hamiltons jetting recommendation is a good place to start.You will be surprised how much better it will be.Opening the carb is easy,just be patient,keep every thing clean & don't brute force it!( no hammer required).Plenty of instruction info on this forum ,but briefly-
Start with a clean,dry bike.
Loosen the rubber boots each side of the carb.
Disconnect the fuel hose.Keep rags handy,there will be fuel leakage.
Rotate the carb top towards you enough to unscrew the top.Jiggle the throttle cable to get enough slack.Carefully pull the carb top off,it will have attached a long spring,a slider & the needle sits in the slider.(tricky bit)Push the spring up to the cap,the cable end sits in a slot in the slider.Push the cable down & sideways to unhook.Slider will now be separate from the spring/cable.Put a socket in the top of the slider (5mm I think?),undo this & tip the slider up for the needle to fall out.Note what numbers/letters are on the needle & which slot the little circlip is in.Tip-take photos as you go.
Put a bit of clean rag in the top of the carb & rotate it away from you.You may need to remove the 17mm bolt at the bottom.Rotate it enough to undo the 4 screws that hold the bottom of the carb (bowl) on & remove.
Remove the main jet gently (brass hexagonal thing with a hole in the middle-6mm socket).
Remove pilot jet (brass screw with a hole through it, set deep in a hole,need a slot/spade screwdriver)make sure it is a good fit as you don't want to damage this & not all screwdriver have a thick enough end with a narrow shaft to fit.
Note numbers on each & post it up.
Have a beer,smell the fuel fumes in your garage -you just earned a new man badge.

All great advice! I'm with them.

Plus, its a new plug. You could grab a magnifying glass and check down in the base of the insulator and check the fuel ring. There does appear to be some colour forming on the plug, as opposed to white ash. You can also check for any aluminium flecks which will be present if it was pinging hard.

All in all, it's had a lean run. But I very much doubt any damage has been sustained.

There may be some difference between carbs, but on mine, I can just undo the main jet cap on the bottom of the bowl and then get at the pilot jet and main jet without removing the bowl.

Yes don't have to remove the bowl or the fuel hose. Just rotate the carb and remove the 17mm plug on the bottom of the carb and both jets are easily accessible


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