spark plug mystery

[racerxnico]

Working on a project bike and I've come across something odd. Went to pull the spark plugs and they are threaded into some sort of tube, which is then screwed into the head. The tube is about 1.5 to 2" long and has a relatively small opening at the end that screws into the head.

Has anyone seen anything like this before? Is it a crude form of tuning?

confession, this bike isn't a GS, but I'm hoping someone can lend some insight.

thanks,

[ddz]

plug mistery

Someone must have stripped the plug hole & put a heli coil in there .There pretty comon on these older bikes.......you'll see!

[racerxnico]

But, it isn't a helicoil. It is a tube that can be unscrewed independently and holds the spark plug electrode out of the head by about an inch and a half.

[bill acamo]

sounds like antifoul plug adapter

[Anonymous]

plug

Yup sounds like an anti-foul plug adapter

[racerxnico]

anti-foul plug adapter? Can you explain?

[focus frenzy]

anti-foul plug adapter? Can you explain?

anti-foul adapters were/are popular for engines using oil excessivly.
when a engine oil fouls the plugs you put the adapters on and the small hole makes it harder for the oil to get to the electrode and also allows the plug to burn hotter.

if your bike is not using excesive amounts of oil, they may have been installed as some sort of red neck cure for a running problem.

[Anonymous]

They might be there to index the plugs, to allow the electrode to point in a certain way to provide the best combustion, and allow all the plugs to be aligned in the cylinders in the same way.

[SqDancerLynn1]

They might be there to index the plugs, to allow the electrode to point in a certain way to provide the best combustion, and allow all the plugs to be aligned in the cylinders in the same way.

THEY are garbage used on an oil burning engine. It has nothing to do with indexing the spark plugs. Although It is possible to index the plugs by using different thickness spark plug sealing washers