Weird spark plug problem

R

Rene Holsebro

Been Around the Block
My cj360 kills my spark plugs I bought 3sets of spark plugs and within a few days it won't fire, I have a spark from the spark plug to the motor if I hold it a few millimetres away. but no spark inside the plug. then i can buy a new and it works for a while. I have standard coils. What could be the problem
 
reading_spark_plugs.jpg
 
Well they do have some Dark deposits, and im still fiddelling with the carbs, but dont you Think it would be Strange if a too Rich fuelmixture could destroy the plugs
 
How dirty are the plugs? If you clean them off with a wire brush, do they work again?

Are you sure it's the plugs and not the plug caps or wires?
 
They are Black, but i have seen worse. I have to buy new ones , to get it to work . But then it fires right up again. Now I also bought new plug cabs and until now they lived twice as long, but yesterday it only ran on one cylinder for a few hundred meters and then came on both, so I think the problem is coming back
 
Try hotter plugs maybe. Have you looked down into the very base of the insulator? If plugs are too cold they wont self clean and deposits will build up fast.
 
Rene Holstebro said:
Well they do have some Dark deposits, and im still fiddelling with the carbs, but dont you Think it would be Strange if a too Rich fuelmixture could destroy the plugs
Click to expand...
If the carbs are fouling the plugs, it will certainly cause the issues you are having. I wouldn't rule that out at all.
 
What plugs are you fitting? They could be the wrong plug length or heat range.

A few hundred meters is hard to kill even the wrong plug. Check battery voltage, points and condensors. It almost sounds like a coil breaking down.

But you said that the spark would jump from the plug to the head with a big enough gap. That suggests the ignition system can create a high enough voltage but the plugs are a dead short. Are you using some sort of fuel additive or lead?
 
Plugs are NGk b8es, I'm not using anything in my fuel, I run 95oktan unleaded, and teazer, I think you misunderstood me, it ran on one cylinder when I started it but within a few hundred meters, it started to run on both. If I look down into them they still look too fouled, but noting really serious, like the examples shown earlier. I took the right coil with the condenser and had a mc-shop check it, and he said it was ok. I just bought a set of 28mm pwk carbs from stage6 that I want to try on my bike to see if I can get to play nice
 
Im thinking 95 octane fuel coupled w less than ideal compression. Not so great. Or am I mistaken?

Try some lower octane, like 87-90 max.

The higher the octane the harder it is to ignite. Requiring higher compression.

Along w all the usual...did you sync the carbs, adj A/F mix properly...blah blah blah so on.
 
B8 should be hot enough to keep themselves clean. Yes I read that the wrong way round. If it was dead and then picked up as it ran down teh road it is probably clogged filter or exhaust or leaky float valve or pilot jets that have been "cleaned" with an oversized wire. Try to get some new OEM pilot jets and see if that cleans it up. and check float levels or even better fuel level.
 
Thanks i Will try to change to 92 oktan which is the lowest i Can get in Denmark and look at the carbs again, and then try my new carbs
 
Now I installed a set of 28mm pwk' and removed the kn's and are using the stock air box. but it still ruins the plugs, it also runs very hesitant almost exactly as it did with the stock carbs. Could it be the coils that doesn't deliver exactly, or will you guys still say that it is the fuel delivery that causes my problems, if I hold the spark plug 5mm away from the motor it delivers a nice spark, but a very bad spark inside the spark plug if I hold it up to the motor
 
That is probably just the fact that it takes a higher voltage to jump a larger gap. Who jetted the PWK carbs? It could be a similar issue with it being too rich. Try B7 plugs just to see if it lasts any longer as the hotter plug burns it cleaner. That should not be the solution but it might show us what is going on.

You said the plugs are black and that seems to be too rich, but are the plugs wet or dry or oily or just dusty black soot? Let's stick with carbs first. Try smaller (NEW) pilot jets or at least change the air screw to lean it out. And set the float levels again with carbs at an angle.

What air filters do you have on the bike and what exhaust? Some pod filters block the air feed holes. If it has stock filters and air box, are they clean or all clogged and wet?
 
The pwk have 130main and 38pilotjetjet the plugs are maybe a little oily. If I take some of the plugs that was "dead" earlier and was stored for several months, they work a little again.
So maybe they don't clean properly.
The carbs are brand new
I have the stock filters on now, but not a new filter, but it seems pretty ok.
The exhaust is open,photo attached
 

Attachments

  • image.jpeg
    image.jpeg
    1.1 MB · Views: 203
a picture would help

are you running the chinese pwk copies?

like these

http://www.ebay.com/itm/like/161891571809?lpid=82&chn=ps&ul_noapp=true
 
No it's a better, more expensive version, from stage6. But still a copy.
I had a cheap and this in my hand when I got it, and there was a huge difference in quality.
I will post a picture of the plug later.
 
Ok. This Company in Denmark had two different qualities and this one didn't have the casting flaws that the cheaper one had, and I paid twice the price, but maybe I got screwed. but it is the only option I could find if I wanted new carbs here, you guys are used to a larger selection in products and companies, "over there".
 
teazer said:
You said the plugs are black and that seems to be too rich, but are the plugs wet or dry or oily or just dusty black soot? Let's stick with carbs first. Try smaller (NEW) pilot jets or at least change the air screw to lean it out. And set the float levels again with carbs at an angle
Click to expand...
Rene Holstebro said:
The pwk have 130main and 38pilotjetjet the plugs are maybe a little oily. If I take some of the plugs that was "dead" earlier and was stored for several months, they work a little again.
So maybe they don't clean properly.
The carbs are brand new
I have the stock filters on now, but not a new filter, but it seems pretty ok.
The exhaust is open,photo attached
Click to expand...

I absolutely agree with teazer. It sounds like you're running pretty rich. It's not very difficult to correct this, so that's good. Just try and locate a jet kit online (something with the most sizes, that way you have options). If you don't manage to jet properly, you will be continuously fouling spark plugs - and that sucks.

If you're not familiar with re-jetting your carbs and adjusting the float height, trust me when I say it's crazy simple. It'll just take some trial-and-error to nail it.


"You miss every shot you don't make." - Wayne Gretzky (Michael Scott)
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom