Help . . . .fouling plug . .. . .MC-21

**wino** · 31-10-2011, 12:38 PM

I bought a NSR 250 a few months back and it's been great fun to ride and very reliable but now . . . . . .. . ... .

It fouls the front plug in a few K's the tank plug looks good.

There is no pre-mix stuff on this bike all of it was taken off. So I make up the mix on the work bench.

plug gap is 00.07

mixture screws out 2 1/2 turns

and making a 30:1 mix using Motul.

I need some help please as not only is this stopping me from riding up in the hills but it's put a dent in hunt for a job.

Cheers

**wino** · 31-10-2011, 03:00 PM

30 looks no help ?!

c'mon Guys

**Gangus** · 31-10-2011, 03:18 PM

Try fresh plugs.
If it fouls like you say swap l to r and see if that plug comes good on the other lead.
Are you sure your getting good spark on that cylinder?
Mabey an earth...

**Loud** · 31-10-2011, 03:35 PM

Low spark, low compression, rich jets. What have you tried?

Good choice on a commuter by the way.

**wino** · 31-10-2011, 03:41 PM

Originally Posted by Gangus

Try fresh plugs.
If it fouls like you say swap l to r and see if that plug comes good on the other lead.
Are you sure your getting good spark on that cylinder?
Mabey an earth...

done the swap and it's fouling on the front cylinder no idea wheather it's called no. 1 or no. 2

I'm working blind I have no info or manuals at all on the bike

**wino** · 31-10-2011, 03:43 PM

Originally Posted by Loud

Low spark, low compression, rich jets. What have you tried?

Good choice on a commuter by the way.

it has to be a fuel issue cause when I swap plugs it runs great, I guess what I really need is specs and numbers to set this bugger up.

**19andrew59** · 31-10-2011, 03:48 PM

Tried here?

NSR-WORLD • Index

**richarde** · 31-10-2011, 03:49 PM

Do you know what it is fouling with - oil or carbon?

Not sure which cylinder is the front cylinder on an NSR, but if the seal between the gearbox and crankcases is leaking it can suck oil through which could cause fouling. It would have to be a pretty bad leak to foul that quickly though, I would have thought.

If it is fouling with carbon - maybe a stuck choke or some other carby issue on that side?

**Loud** · 31-10-2011, 04:07 PM

I’m confused. It runs fine when you swap the plugs? Then leave them swapped and enjoy your ride.

Unless it then fouls again, in which case check compression/spark/jets. If it has been running fine for months and hasn’t responded to new plugs then I’d say it’s time for a top end rebuild. But compare compression and spark on both cylinders as a quick check first.

By the way, considering it’s likely one of only a relative few MC21s in WA, I’d not hold your breath on specific advice here. Check the NSR World forum and website. Beaten...

**wino** · 31-10-2011, 04:34 PM

Originally Posted by richarde

Do you know what it is fouling with - oil or carbon?

Not sure which cylinder is the front cylinder on an NSR, but if the seal between the gearbox and crankcases is leaking it can suck oil through which could cause fouling. It would have to be a pretty bad leak to foul that quickly though, I would have thought.

If it is fouling with carbon - maybe a stuck choke or some other carby issue on that side?

it's fouling with oil there is no leaks or issues with seals or stuck bits on the carbys, what I was really hoping for was what settings to run this bike on . .. . when the plugs wet you can hear the motor is trying to run through it.

One of the major problems is I have no idea how to tune/diagnose a 2 stroke I got ALL of my years on a 4 stroke until now.

**wino** · 31-10-2011, 04:45 PM

Originally Posted by Loud

I’m confused. It runs fine when you swap the plugs? Then leave them swapped and enjoy your ride.

Unless it then fouls again, in which case check compression/spark/jets. If it has been running fine for months and hasn’t responded to new plugs then I’d say it’s time for a top end rebuild. But compare compression and spark on both cylinders as a quick check first.

By the way, considering it’s likely one of only a relative few MC21s in WA, I’d not hold your breath on specific advice here. Check the NSR
World forum and website. Beaten...

swapping plugs all the time is nothing but short term and a cop out ( plus its fouls too quick )

compression, spark is fine it's a fuel/mix issue I can feel it, what bothers/worries me the most is if I lean out the fuel or the mixture is I'll seize it then I'm phucked cause I cant ride any of the other bikes cause of the brand new license.

I know about NSR world but I want to stay local nothing like getting to know people I might be able to meet one day.

I see you running a RS125 "big block " you might be able to help a bit more

thanks for the reply's btw, it all counts.

**wino** · 31-10-2011, 04:47 PM

and sorry if it takes me a bit of time to answer replys I got a Halloween thing going on at the same time tonight.

**Para045** · 31-10-2011, 05:05 PM

Originally Posted by Loud

By the way, considering it’s likely one of only a relative few MC21s in WA,

According to their details they're in Adelaide not WA so probably even less chance of getting help

**wino** · 31-10-2011, 05:17 PM

Originally Posted by Para045

According to their details they're in Adelaide not WA so probably even less chance of getting help

how true I tried to get a few parts here and there for the fairings hahhahahahahhahahahahhahaaaahahahhhahah

" I gotta a nsr 125 "

eastern states for parts, no choice

**Stevezxr** · 31-10-2011, 05:50 PM

Buy some different oil
Try some of the shell synthetic 2 stroke oil to see if still get fouled
My old rgv had a similar problem when i ran A747 but ran perfect on the shell

**wino** · 31-10-2011, 07:14 PM

Originally Posted by Stevezxr

Buy some different oil
Try some of the shell synthetic 2 stroke oil to see if still get fouled
My old rgv had a similar problem when i ran A747 but ran perfect on the shell

I did that this very day I went from Motul to Shell and no diff bugger runs good for a short time then fouls the front plug you can feel it strive to run on both plugs but no go.

the only info I'm working with is 0.07 on the plugs and 2 1/2 out on the mixture.

Like I have said b4 clean plug the thing gets up and screams, but I need to stop it fouling so fast . . . .. . .

**Stevezxr** · 31-10-2011, 07:26 PM

So the comp is good
the only thing it could be is spark
If it was getting to much fuel it would pop and back fire once fuel built up in the exhaust
So if its not back firing it might not have enough spark

You might need one of these
NSR-WORLD.COM

Not this exact one but one for your bike

**wino** · 31-10-2011, 07:32 PM

Originally Posted by Stevezxr

So the comp is good
the only thing it could be is spark
If it was getting to much fuel it would pop and back fire once fuel built up in the exhaust
So if its not back firing it might not have enough spark

You might need one of these
NSR-WORLD.COM

Not this exact one but one for your bike

Fair call Steve but it's not spark,cant be I need to find out carby and mix settings

NSR-WORLD.COM

a link to a brake hose seperater ?

wat ?

**wino** · 31-10-2011, 07:35 PM

just saw the coil pack on the right, my bad steve ^

**Stevezxr** · 31-10-2011, 07:40 PM

Wrong page Doesn't matter

I would have thought if it was a air fuel mixture problem it would still back fire the only way it couldn't is if it was running lean and that wouldn't cause the plug to foul

Get one of your mates to stick his finger in the plug lead and give it a really good kick if his hair stands up its all good if not get him to try the other side

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