Oil-fouled plugs

**Rupe** · 6th August 2007, 19:14

[QUOTE=F5 Dave;1160801]He is actually running more oil than the predecessor, 40:1 rather than 50:1 (sez in another post).QUOTE]

No it was the other way round. he was running 40:1 but after I fouled a plug I changed to 45:1. After another fouled plug I went to 50:1 as 50:1 is what the manual states. But is this making it more likley to foul?????

The manual states it should have a br8eg, but it had a br8es in it (which I fouled). When I first got the bike I took it to muriwai a few times to get used to it, so I would of been opening the throttle a fair bit.

Basically when I've fouled the plugs is going round the dead wood bit up woodhill, which I'm slow round and the bike is prob idling quite a bit. Then I come up the road with the bike ticking over so I don't run any kids over, and have a break (prob without turning the fuel off, can't be sure). When I get back on the bike when I've opened it up it dies, fouled plug, new one in, runs fine.

Not too sure if the bike leaks fuel with the tap on and on the stand, but I think it could do I'll have to check. I know it leaks fuel with the tap on while being transported in the trailer as I could see fuel on the trailer deck when I stopped on the way home a couple of weeks ago.

Anyway thanks very much for the help so far.

**laRIKin** · 6th August 2007, 20:43

Read this and it may help.
And read the part after the stop sign just down from jetting and you will under stand what you have done, better than I can type.

http://justkdx.dirtrider.net/printcarbtuning.html

**Danger** · 6th August 2007, 21:11

Running less oil makes your bike run richer. Less oil, the fuel droplets are thinner and pass through the jets easier. I know it sounds funny, but its a fact. Its fuel, not oil that is causing your plugs to foul. A 200 should be run on 32-1 oil ratio. 250's at 40-1. Oil provides the lubrication for your crank and seals your piston rings on compression. A faster reving engine like a 125 requires more oil than a slower rever like a 300 or a 500.

**Rupe** · 8th August 2007, 20:32

Ok, after having a read through a few bits of info I see it is best to change the fuel ratio to 40:1.

I also remembered that the bike was idling a bit low so I just gave the idle speed screw a twist to fix it. Maybe I should have adjusted the air mix screw too as it may be running to rich at idle to 1/8 throttle. Could something this simple also be the reason?

Thanks heaps so far for all the help

**F5 Dave** · 9th August 2007, 09:21

well its a start, Did we ascertain if the airfilter was clean & oiled with air filter oil?

**Aero165** · 9th August 2007, 11:13

What oil are you mixing with the fuel? I was using Yamalube on my YZ and I was fouling 2 plugs to every 1 ride sometimes(I don't ride like a nana either) I then switched to castrol tt-s and I haven't fouled a plug since.

My mechanic reckons it has something to do with the oil separating from the fuel in colder temperatures.

Thats my 2cents. Hope it helps

**cheese** · 9th August 2007, 13:20

Yeah I'm in teh TTS fan club, I got sick of paying over the top prices for motul.

**vr4king** · 9th August 2007, 14:04

Originally Posted by cheese

Yeah I'm in teh TTS fan club, I got sick of paying over the top prices for motul.

Plus it smells good........Which reminds me i need some where you guys buy it from,I normaly go supercheap autos

**cheese** · 9th August 2007, 14:57

Yeah wait for a big supercheap auto special and get it then. Or ask Booom, you have to get it it bulk though and you only save a wee bit.

**Rupe** · 9th August 2007, 17:41

Originally Posted by F5 Dave

well its a start, Did we ascertain if the airfilter was clean & oiled with air filter oil?

I clean and re-oil the air filter with air filter oil after every ride.

The oil I've been using was what the guy gave me with the bike, it's fully synth, motorex oil????? Anyone heard of it/rate it.

**Rupe** · 11th August 2007, 18:26

Ok went up Woodhill today to have a run, and try to sort out the plug fouling problem.

I went back to running 40:1 instead of 50:1 to see if that would help. And I adjusted the air mix screw on the carb, (as I sdjusted the idle speed and not the air mix).

This didn't help, it was fine on the trails, but it's seems to be when I gently cruise up the main road to my car this is when I'm fouling plugs. And they are wet when I pull them out. I was also thinking it might be that I'm putting to much oil on my air filter, but then again the bike is fine when you open it up.

So basically I'm no further ahead, any ideas would be great.

Another thing that I was unsure of was if I'm adjusting the air mix correctly. I'm assuming that 1 1/2 turns would be turning the screw 540%???

Also I opened and clean the carb in the week, and I was thinking today that by turning the black plastic idle screw to make it idle quicker, did I move the whole jetting needle? Should I make it slower again.

**dammad1** · 11th August 2007, 22:49

The Jetting must be out, take it to some one who knows what they are doing, pay the money and sort it out once and for all so you can actually enjoy riding it like your suppose to.

**Rupe** · 11th August 2007, 23:11

Originally Posted by dammad1

The Jetting must be out, take it to some one who knows what they are doing, pay the money and sort it out once and for all so you can actually enjoy riding it like your suppose to.

No thanks, I'd rather learn to sort out the minor problems myself. prob come in useful in the future and I'm enjoying fixing the little problems, and the riding thanks.

**Buddy L** · 12th August 2007, 10:13

I was putting a bit to much oil on my filter at one stage, but his only ended up making the bike run more smokey then normal. Is the main jet standard size? if you just puttering around the car park with a over size main jet? maybe?
http://www.snowvalley.20m.com/bikes/jets.htm
Have a look at this might help!