Centrifugal Centrifugal Clutch Inoperative

[gatedude1]

Worked out all starting issues.Replaced bent needle valve,installed o ring on intake and replaced the spark plug and changed the gap. Now it starts on the first pull. Forgot to add also went from 16 to 1 to 24 to 1. Runs great and everything was great until yesterday the clutch started slipping and it's getting worse. Could the centrifugal clutch be slipping on the crankshaft? Tried tightening but that didn't help. Is there a way of installing a woodruf key on the gear of the clutch. Any help would be appreciated without the search and fix method for I have looked for a fix and haven't found one so far on the forum.

 

[Fabian]

The clutch gear is normally attached to the output shaft with a woodruf key.

It is quite possible that you need to increase the preload tension on the manual clutch plates by winding in the flower nut by two index positions.
Remember to use a small amount of Loctite 222 when reinstalling the flower nut set screw.

After you have adjusted the clutch, the slippage should stop, or be minimal as a new clutch beds in.
If it keeps slipping, or the slippage gets worse, then it's possible the press fit of the gear attached to the centrifugal clutch has failed (assuming that the bolt holding the centrifugal clutch to the crankshaft is firmly affixed); allowing the press fit gear to spin inside the centrifugal clutch housing. Although an unlikely scenario, it has happened to me (once), and in such a case, you will 100% know that something is wrong; with a feel and sound of grinding and grating coming from the clutch housing.

When one of my clutches failed in this manner, it looked perfectly ok when disassembled. I actually needed to apply a bit of force to the gear (with multigrips) to get it to wiggle about; enabling a visual indication that the press fit had failed.
That exercise was a huge, huge, huge headache because i reinstalled the failed (though externally intact) clutch, 3 times, trying to work out what the problem was.

 

[gatedude1]

Will give it a try and hopefully that will be the fix.Thanks for your quick response.

 

[Fabian]

To better understand how the mechanism works, and how to do an essential modification to ensure the centrifugal clutch operates with long term reliability, do a Google search for both:


"Centrifugal Clutch - 48cc, 60cc, 66cc, 80cc - pull-start/pedal-start, 2 stroke"


"Lubrication port > Modified Centrifugal Clutch - 48cc, 60cc, 66cc, 70cc, 80cc - pull-start/pedal-start, 2 stroke"

 

[gatedude1]

Hi Fabian
As it turned out the clutch was quite a bit out of adjustment.I had to turn the buterfly nut almost 2 turns before it would quite slipping. Now it will idle with the clutch engaged . Sorry have been away.