OzVMX Forum

Marque Remarks => Yamaha => Topic started by: ELC hunter on July 19, 2010, 02:10:11 pm

Title: IT 250J kills spark plugs
Post by: ELC hunter on July 19, 2010, 02:10:11 pm

A friend has it 250 j that kills plugs within half an hour of riding doesnt matter what brand kills them stone dead.bike has head light  but not sure if its hooked up,fuel is 25:1 mineral oil .Any hints it has only basic wiring dont know if any regulators ars still in system.ELC hunter.

Title: Re: IT 250J kills spark plugs
Post by: cyclegod on July 19, 2010, 03:44:39 pm

try a resistor plug cap, 5ohms I think?

Title: Re: IT 250J kills spark plugs
Post by: ELC hunter on July 20, 2010, 01:36:23 pm

thanks i will get him to try it ,the head light works orignal switch gear no tail light used normal kill switch.Will see what happens.

Title: Re: IT 250J kills spark plugs
Post by: Lozza on July 20, 2010, 01:53:11 pm

 standard plug caps are 5 kOhms non restor plugs have 0 ohms. Make sure you don't have a resistor plug and resistor cap. Otherwise check jetting

Title: Re: IT 250J kills spark plugs
Post by: dave on July 20, 2010, 07:31:18 pm

What do the plugs look like after they die?

Title: Re: IT 250J kills spark plugs
Post by: head on July 21, 2010, 04:16:39 pm

What brand petrol are you using? ???

Title: Re: IT 250J kills spark plugs
Post by: retrowrex on July 21, 2010, 08:35:27 pm

Ah the mystery of the murdered spark plugs. Once upon a time in a dark and distant past, a bike rider would place a new spark plug into a bike and ride for months, if not years.  Sometimes the plug would oil up when the rings were sorry and foul.  As technology advances and fuel improve, spark plugs seem to last less and less.  Ready to foul at the slightest excuse.  Some say dodgey electrics.  Some say dodgey fuel.  I have about 6 2 strokes running between the family. Some old and some new.  All of them have fouled plugs and are keen to at any given time. Has a near new YZ125 foul and plug and when I went to get a new one on my WR2502t, it fouled one.

The modern fuel sucks as much as the new spark plugs. You remember when you used to leave some fuel in a container it would all evaporate in a couple of hours.  Leave the same amount of ULP now and your are left with an oily residue.

Only use the freshest fuel.Use the left over in the mower. Empty what you don't use  Keep a good supply of spark plugs.  I use sythetic oil at 40ish to 1.  Mobil premium fuel i find the best, Caltex then BP.  No others.  Not Optimax from shell.  Have bee told it is frm the devil.

Title: Re: IT 250J kills spark plugs
Post by: head on July 21, 2010, 11:59:02 pm

That's what I was getting at. I have heard heaps of people having problems with shell Optimax. Great in fuel injected cars. Not so great in 2 stroke motorcycles.

Title: Re: IT 250J kills spark plugs
Post by: retrowrex on July 22, 2010, 06:51:48 am

I still seem to foul on any fuel, in all of my bikes.  No paterns.  Ordered some denso plugs yesterday.  If nothing else it the different plugs in the pile of dead ones lying around with be a change.

Title: Re: IT 250J kills spark plugs
Post by: Mike52 on July 22, 2010, 08:34:39 am

Back in the day I was supposed to use Bosch plugs but being poor [ spent all munny on bike ] I purchased some champions and Jap stuff.
The champions were good ,when they died you left them to cool down and volia they came back to life.
The Jap ones just died.
Sold the wife and bought Bosch. :)
Not just running lean is it?

Title: Re: IT 250J kills spark plugs
Post by: ELC hunter on July 25, 2010, 08:32:37 pm

No not running lean new crank seals /base head gaskets.As for bad fuel I don't know these old yams would run on kero ,I suppose it is proably more volitle than todays fuels.

Title: Re: IT 250J kills spark plugs
Post by: evo550 on July 25, 2010, 10:01:28 pm

Can you give us a description of the plug when it fails.