Centrifugal clutch doesn't disengage

T

TripTheDog

New Member
Hello everybody, I'm new here and this is my first post. I've been playing around with these bikes since i was fourteen. For my latest build I bought a PK80 2 stroke engine and decided to add the centrifugal clutch/ pull start combo to it. The pull start was a piece of cake and no problems there. The centrifugal clutch is another story. I believe i have it installed according to the directions but i cant get the thing to disengage at idle. I've tryed playing with the engine idle on the carb to no success. I was wondering if anyone else ran into this problem and figured out a solution. I can take pictures if needed, just let me know what you need to see. Thank you
 
Pictures would certainly help.
I gotta ask though, is it a problem of the rear wheel spinning while it is lifted up off of the ground or is it that the engine will stall when the rear wheel is prevented from turning?
 
and the centrifugal clutch spins freely in reverse but engages immediately in normal operating rotation with the engine not running
 
While I have not had this problem myself, others here have.
The knowledge I have is what I recall from their experiences.
Considering that you already stated that you tried to lower the idle speed (and I assume that you tried lowering it until the engine died and the clutch still stayed engaged)...
The first idea that comes to mind is the spring that acts like a one way starting clutch may be on backwards.
Second idea, There may be an issue with the clutch drum getting stuck (read pinched) to the clutch hub when the center bolt is tightened.
 
that would make sense. is the starter spring inside of the centrifugal clutch? and if so how do i take apart the centrifugal clutch
 
if it isn't starter spring, then its too high idle speed causing engagement. Give engine about 2-3 hours of use and idle should come down and clutch surfaces will wear away a little improving your situation.
 
There should be a hair pin spring clipped to the backside of the clutch. Just remove it, flip it over, and reinstall it.
I am going to go out to the garage and look at mine. It has been years since I removed it and I am a bit fuzzy on the details right now, gotta be sure I am not talking BS right now!

Here are some threads on the clutch. Some relate to what you need, some relate to what you may need in the near future.
http://motorbicycling.com/showthread.php?t=9877#post95601
http://motorbicycling.com/showthread.php?t=17162
 
Ok here's what i did. I took apart the centrifugal clutch and found out that i was missing the hairpin spring that you pointed out in your video. I also noticed those five grooves where the roller bearing sits. those grooves appear to be there to lock up the centrifugal clutch in one direction( much like a ratchet). I assume they do that to allow for bump starting the bikes. well i have a pull start so what i did was take the rollers out of the bearing so that it can no longer lock up until it reaches the certain rpm.
http://s1266.photobucket.com/albums/jj522/TripTheDog/?action=view&current=ccarrows-1.jpg
 
Hmmmm...
From what I understand the one way bearing affect is accomplished by both the roller bearing and the hair pin spring working together as an assembly.
Now your clutch seems to be a different breed than mine? It still has a one way affect without the spring? Are the bearing lands in your clutch's bearing carrier angled like in a sprague clutch or are they standard, straight out from the center line of the shaft center?

Well, as long as the clutch drum will still have proper support without that bearing assembly in there I guess that you will be good to go. Or can you flip the bearing around to give the drum better support and still have a one way bearing affect only now in the correct direction of rotation?
 
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