Fouled plugs

[thorns]

Would this be considered a fouled plug? 270097

Just taking my bike apart and giving it a look over.

[paturoa]

Needs better photos, but from what can be seen, probably.

Also what sort of plug and what is the bike? Also what sort of riding were you doing immediately before you took the plug out?

[thorns]

Plug is a ngk br8eg

Bike is a rm250 2009.
Last time riding was my first time on it, so was lugging it round and getting used to the bike which I suspect could be a cause of it.

What would be the best way from here seeing as I am not going to be ringing it's neck for a bit of time til I get back up to speed? Would changing the jetting bit help? Leaning low speed jets etc?

[bogan]

The back of the ground strap kinda covers all the important bits in the photo...

[bogan]

Plug is a ngk br8eg

Bike is a rm250 2009.
Last time riding was my first time on it, so was lugging it round and getting used to the bike which I suspect could be a cause of it.

What would be the best way from here seeing as I am not going to be ringing it's neck for a bit of time til I get back up to speed? Would changing the jetting bit help? Leaning low speed jets etc?

Find a mate who can ride it properly every other couple of laps for ya! I wouldn't change the jetting, though you might be able to change the amount of oil in the pre-mix, but don't take my word on that cos I'm not 100% sure. Imo your best option is to ride tracks/trails where you can spend a fair bit of time in powerband, it's what the 2Ts are made for.

[sootie]

Would this be considered a fouled plug?

Just taking my bike apart and giving it a look over.

Possibly! It looks far from perfect.
Put any multimeter across it and select the highest resistance range (if it is not a digital meter which does this automatically).

If the multimeter shows any resistance reading other than infinity, then there is a degree of fouling.
Unfortunately the reverse is not true. (ie infinite resistance does not confirm that there is no fouling.)
(The multimeter measures at low voltage, but the plug needs good insulation resistance up to thousands of volts.)

It would probably be possible to burn off any fouling, but this may or may not be easy to do. If the fouling is slight, and the bike still runs pretty well, a good long run will probably solve any problem. I hope this helps.

:lol:

[curly]

Need a photo like this
270098

[sootie]

Need a photo like this

Nice clear helpful photos - proabably the best I have seen. :niceone:

[thorns]

Need a photo like this
270098

Cant get my camera to focus that well.

But from that picture, it looks perfectly like the wet fouling one, could that just be a case of flooding the motor?
I had started it this morning and it started up all fine, let it idle for a couple of minutes, and then it died and couldnt get it started again.

[curly]

TBH I don't know but how much oil did you add to the petrol? Because too much oil can possibly foul the plugs.

[paturoa]

An 8 is probably already hot enough. I agree with bogan and don't fark with the jetting just yet.

Lugging around at low revs will do that.

For standard carbs re-jetting is mostly about large throttle openings where the size of the main jet comes into play. Lugging around at low revs is mostly tuned using the pilot screw. Do some reading on how to adjust this before you do anything. If you do then note the position of the screw before you start turning. Write it down in a note pad because you will forget.

Go get yourself a couple of new plugs (and a bum bag to take with you on rides too).

I'd start with cleaning the air filter, draining the petrol (use it in the cage), take the float bowl off and clean that too.

Buy some nice new 95 petrol and a good fully synth 2smoke oil. Refuel with nice new stuff and USE THE THROTTLE MORE.

Then see what happens.

If your cheap like me, then get some plain malt vinegar and immerse the business end of the plug for 24 hours and then give it a clean. This will revive most plugs and give you a backup plug for your bum bag.

[thorns]

Thanks guys, was running 95 gas, with 30:1 as per manual specs.
However just after talking to previous owner he was running 32:1, so will run that with a new plug and see how I go before playin with things I dont know a lot about :confused:

And also, will strap on my big boy boots and twist that throttle more any chance I can :laugh:

[Jinxycat]

Welcome to the fun world of jetting a MX 2t to run in an enduro environment :D

[gwynfryn]

You need to read up on jetting.

The oil ratio will not affect the fouling too much it is unburnt fuel that creates the carbon and spooge. Too much fuel=more fouling. Use a good(synthetic) oil and stick to the same ratio. 40:1 would be good if you are not racing motocross but 32:1 is also fine .Just stick to a ratio.

It sounds like your pilot circuit is too rich.This is a combination of air screw and pilot jet. A correctly jetted bike will idle all day and not foul plugs not to mention pull well and provide excellent throttle response right through the rev range.

To get the most out of your 2st bike you need to understand how the carb fuel circuits work.See if you can't find out what other pilot and main jets as well as needle clip position others are running for your bike(at similar alavation) and use this as a baseline.

Good luck

[bsasuper]

Here's something to read, most off road bikes have the carbs/fuel injection running on the rich side, to give better throttle response, hence dirty fueled up plugs.

[Boo]

Here's something to read, most off road bikes have the carbs/fuel injection running on the rich side, to give better throttle response, hence dirty fueled up plugs.

Yes all manufactures specify jetting that is to rich because they don't want you to blow it up and blame them. Temperture, humidity and elevation change jetting, either to rich or lean.
Run 33.1, do a plug chop and go from there, looks to me you could run one jet down on the pilot, is it bubbly when you go from 0-1/4 throatle, running rich is not a bad thing but when its fouling plugs it could go a tad leaner. Whats the compression like.

[Boo]

Here's something to read, most off road bikes have the carbs/fuel injection running on the rich side, to give better throttle response, hence dirty fueled up plugs.

Yes all manufactures specify jetting that is to rich because they don't want you to blow it up and blame them. Temperture, humidity and elevation change jetting, either to rich or lean.
Run 33.1 and 98 from BP, do a plug chop and go from there, looks to me you could run one jet down on the pilot, is it bubbly when you go from 0-1/4 throatle, running rich is not a bad thing but when its fouling plugs it could go a tad leaner. Whats the compression like.

[eelracing]

Plug is a ngk br8eg

Bike is a rm250 2009.
Last time riding was my first time on it, so was lugging it round and getting used to the bike which I suspect could be a cause of it.

What would be the best way from here seeing as I am not going to be ringing it's neck for a bit of time til I get back up to speed? Would changing the jetting bit help? Leaning low speed jets etc?


Mate for now chuck in a new plug and turn the carbs air screw out (anticlockwise) half a turn from standard.
Standard air screw setting for the RM is one turn out.
Turning it out will increase the airflow therefor leaning out the idle to 1/4 throttle air/fuel mixture and hopefully no more fouling.

It's good two stroke practise to always carry a spare plug on any ride.See how you get on.

[gammaguy]

Plug is a ngk br8eg

Bike is a rm250 2009.
Last time riding was my first time on it, so was lugging it round and getting used to the bike which I suspect could be a cause of it.

What would be the best way from here seeing as I am not going to be ringing it's neck for a bit of time til I get back up to speed? Would changing the jetting bit help? Leaning low speed jets etc?

It was built by the factory as a race bike not for someone to pop down to the shops on

Either ride it the way it is designed to be ridden or buy a peewee.

Read the manual if you want to jet out for bumbling around on, but don't forget to change things back when you start to ride it hard

[Blagger]

This pic was originally produced by Champion IIRC - I've seen it stapled to plenty of garage walls

May be of some assistance