OzVMX Forum

Clubroom => Tech Talk => Topic started by: bigk on August 18, 2009, 10:32:59 am

Title: Spark plug failure
Post by: bigk on August 18, 2009, 10:32:59 am
Well it seems my long push across the Barabool hills is due to the electrode falling off the spark plug. My question is what causes the side electrode to fall off on a new spark plug?
Cheers,
K
Title: Re: Spark plug failure
Post by: TeeBone on August 18, 2009, 11:11:20 am
It seems that you mozzed yourself - didn't we speak about hard the push was from "over there" back to the pits? ;D
Title: Re: Spark plug failure
Post by: Ji Gantor on August 18, 2009, 11:53:42 am
The electrode arm is welded on at the factory, so may be you got a poorly welded one (bizzar).
What was the ambient temperature at the time?
You did not drop the spark plug before you installed it?
Is the length of the threaded area too long for the engine, may be the piston hit it.

Ji
Title: Re: Spark plug failure
Post by: Viper666 on August 18, 2009, 01:58:21 pm

I dont know if you have been to a race where RT Motorcycles has had a stall setup but a few years back he showed a 1/2 bucket full of said spark plugs. I wont say the brand or particular plug in case I remember wrong (That's goodly English) but I still use that brand and never had it happen to me. The company involved denied any responsibility, of course, as there were quite a few destroyed engines cause of it.

Viper666
Title: Re: Spark plug failure
Post by: bigk on August 18, 2009, 08:39:19 pm
Been around spark plugs for a while Ji, and know not to drop them. There's no way the piston could hit it even if it came of the rod, (Husky CR360, flat top). It cost me a piston kit, but otherwise OK. Got me beat as to why though, must have been a crook one. I wonder if the rep will acknowledge my claim  ::).
Cheers,
K
Title: Re: Spark plug failure
Post by: Lozza on August 18, 2009, 10:29:01 pm
Will be either fuel or ignition.
Title: Re: Spark plug failure
Post by: Ji Gantor on August 19, 2009, 07:40:58 am
Sorry BigK,
I did not mean to upset you just offered some suggestions.

Ji
Title: Re: Spark plug failure
Post by: bigk on August 19, 2009, 09:12:03 am
Not upset at all, no need to apologise.
Cheers,
K
Title: Re: Spark plug failure
Post by: TeeBone on August 19, 2009, 01:04:29 pm
Many moons ago, I had the same thing happen - except you could see the poor weld remains on the plug - no penetration at all. "Luckily", it blew out an exhaust valve!
Title: Re: Spark plug failure
Post by: bazza on August 19, 2009, 07:10:48 pm
probably the 1 faulty welded one out of a million.Once sold my Radial finn 400 to a guy,next meeting he was on about does not start,did the petrol etc questions-turned out he had put in a new plug,no spark,ok he said heres my spare new plug and still nothing,went and got old plug out of my mag Husky and first kick it started .What are odds of 2 dud new plugs?