Rings to fit Invader Piston

[gixxer6]

Have you checked the other jet sizes?  If the needle is mismatched I would suspect the other jets may be mismatched also... 

When you mention the 4 and 8 needles, I assume you mean 6dh4 and 6dh8?  79' 440 Invaders came with 6dh4's and 81's came with 6dh7's.  I doubt that the mismatched needle would be enough to cause engine failure. 

Running without an air box on these power-jet carbs is a big no-no.  They need the extra vacuum created by the air box to function correctly. 

[sprocket]

A air box. & a windshield

[Macs80hp440]

UPDATE:  I took the motor apart to inspect the breakdown (as listed in this discussion).  It has nothing to do with original piston and aftermarket rings.  It had nothing to do with air leaks or poor break in process.  It is as simple as a circlip coming out.  In fact, the aftermarket piston with matching aftermarket rings is the bad piston.  The Original Kawi Piston with aftermarket rings is fine. 

Notice the grooves under the rings and the chipped piston is because the circlip must have hit it.  The one side circlip made grooves on its own side, then must have moved across under the piston and made grooves on the side that still had a circlip.  The rings seemed intact and the piston seems fine except for a chip missing from where the circlip came up from underneath and broke it out. 

There are two types of clips- one that has a small bend across the opening, and the type that just sits in the groove with no bend across the opening.  The one that came out is the one without the bend...  Notice the other circlip with a bend is still in place.

Evidently I did everything fine except using an inferior circlip.  @!#$ smallest and cheapest part in the motor.  I was 3/4 into a break in process.  I thought it was one brief adjustment that ran slightly lean (grayish tan), but it looks like it had nothing to do with break in or adjustments to mixture.  The circlip came out and wrecked the jug and piston.

I plan on doing it all over again.  I'm pretty sure the crankcase has bits and pieces to clean out.  aarrrggghhhh

[gixxer6]

Ouch!  Sorry for your bad luck!  If you need any parts let me know, I think I've got some good used cylinders and pistons.  I might even have a NOS piston. 

[kawhead]

oem kaw clips have no tab...i've seen a couple tabs break off from vibration?....i've used a few spi piston kits for myself and others,with good results and reasonably priced.