Disaster in the making By FACE PLANT FOR LIFE (Read 483 times)

[FACE PLANT FOR LIFE]

So my dad finally got a scooter. A 150cc! Looks great, only has 400 miles on it. But that's about all that's good so far. Went to go check for spark today, and sure enough, it has spark. So we're putting the spark plug back in.....................and in........and in..........and hey look, it never stops turning. Explains why the spark plug was fingertight when we took it out So...the spark plug threads are SHOT. What do we do?

[kz1000st]

Everyone will tell you to take off the head and put in a helicoil. I like to live dangerously. I would put grease on the threads of the big tap, tap the head and install the helicoil without taking the engine apart. The grease should catch most of the chips and as a safety measure spin the motor to blow out any loose chips through the spark plug hole or exhaust valve. Then put in the plug.

[FrankenMech]

I have done what KZ says several times with no problems. I usually use compressed air with a thin tube nozzle to blow out chips if I can. A little WD-40 will help loosen chips that are stuck in grease. Rinse and clean several times while moving the piston.

Be very careful to align the drill and tap.

[twowheeler]

A flexible magnet will help remove stuff too.

[FACE PLANT FOR LIFE]

Can't I just replace the head, also? Might be the best method, as my dad is not into that whole tapping thing. In fact, it had pretty low compression, and I wanted to do a valve adjustment, but he wouldn't let me because he wants to tear the head off!!

[kz1000st]

Then you have your answer already. Scrappydog sells both stock and performance heads at a really good price as do many others.

[Bashan]

For the price I would replace the head, you'll spend almost that much installing the coil. When you read in the manuals that you have to do the base gasket too, I would try it without doing that. Be careful to not rock the cylinder back and forth a lot and you should be OK. Make sure you get the timing right. It's hard to mess that up though, if you're a chain link off it will be very apparent. However, it certainly happens from time to time.

[tvnacman]

Dec 7, 2013 14:29:56 GMT -6 twowheeler said:

A flexible magnet will help remove stuff too.

Aluminum is not attracted to magnets .

PM sent .

John

[Guitarman]

Dec 7, 2013 18:30:31 GMT -6 tvnacman said:

Aluminum is not attracted to magnets .

Apparently, neither are hot brunettes.... LOL

[tvnacman]

I prefer redheads .

John

[Alleyoop]

Dec 7, 2013 17:47:45 GMT -6 Bashan said:

For the price I would replace the head, you'll spend almost that much installing the coil. When you read in the manuals that you have to do the base gasket too, I would try it without doing that. Be careful to not rock the cylinder back and forth a lot and you should be OK. Make sure you get the timing right. It's hard to mess that up though, if you're a chain link off it will be very apparent. However, it certainly happens from time to time.

If your going to take the chain off the Cam and take that out or whatever DO THIS BEFORE you undo anything:

1. Bring it up to TOP DEAD CENTER
a. Look at the Flywheel and mark the flywheel where the pointer on the case is pointing to.
b. then mark the chain and sprocket

That way there is no way you will be off on the timing.
alleyoop

[jct842]

One other alternative would be the tap thing but going to the next larger size plug. A few of the auto supply stores lend tools and if you did not have to buy the tap that would be the cheapest way. I would go that route and if it did not work all your out is the price of a plug and then go buy the new head. john

[tvnacman]

have you dumped the oil to see if there are any metal bits and pieces in it ?

John