Clutch Operation

[NitroNewb]

I need to understand how my clutch and 2 speed tranny work.
I've had it apart. I imagine as speed picks up the pads flare out against the springs tension and apply pressure to the clutch bell. But what makes it jump into 2nd gear and back to 1st again. I mean physically, what happens.?
I need to get a picture in my mind.
Thanks
GHM

 

[nitrogator]

1st gear rides on a one way bearing as the rpms go up a centerfugal (sp*)clutch engages 2 nd gear and first gear disengages and spins on the one way bearing this is what i was told when i asked this question.i would see if anyone else has a better info

 

[NitroNewb]

Not enough detail.
How does the centrifugal clutch engage the gears?
I know the pads put pressure on the clutch bell.And it increases with speed. But how does that make it shift?
GHM

 

[nitrogator]

i believe the centrifugal clutch expands with rpm moving second gear in to place and disengaging first gear it is all done by rpms....maybe someone can be more descriptive this is what i was told by my lhs when i asked the question

 

[Cupooterluvr]

On my Exceed, there's a hook that comes out and grabs onto the second gear, giving that distinctive instant RPM drop.

There's a hook with a metal bit on the second gear that spins freely until the little drum clutch with the hook swings out and grabs it.

 

[Rolex]

There's a round wheel type device with a spring loaded arm in its' center. When it comes up to speed, the arm extends against the spring tension and locks against a cog, turning the 2nd gear. When slowing down, the arm returns.
Unlike the CB, this arm is not trailing like clutch shoes, but comes out in front and locks in instantly. No slippage.

 

[NitroNewb]

Where is this "round wheel type device with a spring loaded arm in its' center?".
This is what I have. The clutch bell has 2 gears (large and small) and the center gear housing has 2 matching gears.
When both get mounted to the plate,don't both gears line up and mesh? I'm missing where the shift is.

 

[Cupooterluvr]

See that little metal drum to the left of the smaller gear on the tranny? That's the two-speed module. If you look closely, you'll see a little arm in a groove (in fact at the very bottom of the drum on that picture you can just barely see it). Once it gets up to a certain RPM, it pops out and grabs onto the little plastic arm on the smaller gear.

You can adjust the RPM setting at which it comes out by turning the little screw on the side (not the one in the middle, that's the set screw). Turn it to the right for later, left for sooner.

 

[NitroNewb]

I see what your talking about.I see the metal arm and the piece on the smaller gear it would grab. But with both gears on the clutch bell being one piece and in constant contact with both separate gears in the center gear housing, aren't they both spinning all the time anyway.? How does that arm grabbing the smaller gear make a difference if there both spinning already?

 

[Cupooterluvr]

There's a one way bearing on the first gear. Both gears spin at a constant speed, with the second gear spinning faster than first, but until the second gear kicks in, the shaft the gears ride on moves the same speed as the first gear. After second hits, it goes as fast as the second gear, and the one-way on the first gear disengages and the shaft rides freely under the first gear.

That's why you hear the sudden shifting of high rpm to low rpm from the engine when it shifts. The engine has to rev up to the same speed as before only this time the force is going through second gear, which spins faster than first.

 

[Rolex]

Here ya go. I had the 2 speed left over after the 3 speed conversion, but this is what's happening inside to make it shift...

There's a thin arc like shoe held in this closed position by a spring. On the opposite side is the adjustment screw.

I've rocked it out with my thumbnail here. It would be turning counter clockwise.

The 2 'nubs' are what that shoe would hit and lock against to engage 2nd gear.
The groove is where the allan key goes in to adjust the shift point.

 

[NitroNewb]

Understood. Thanks for the detail Cupooterluvr and the great photos Rolex.
Not to beat a dead horse...but....Are there different kinds? Does yours catch on the inside and mine on the outside of the 2nd gear?

It looks like my "nub" is on the outside of the gear.And only one where you have 2.
GHM

 

[Cupooterluvr]

Yep. There are different kinds. On my Maxx it has two just like Rolex's. I guess that's for durability, so that it isn't always hitting the same spot. My Exceed buggy has only one just like yours.

There's also a kind that has a clutch like the one on the engine rather than a hook. That one just works with centrifugal force. Not sure how they adjust but as you can imagine it is much easier to explain.

 

[Rolex]

Any type of clutch would be adjusted by spring tension, just like the shoes in the CB, or the cog in the above pic.
The tighter the spring, the higher the RPMs need to be to bring it out.

 

[NitroNewb]

Makes sense. Thanks for the visual.
GHM

 

[2000delux]

Mine has the c. force type - basically has a 2 half circle shoes attached to each other with springs and screws so they can be pulled apart juust slightly, this sits in a housing so that when a certain rpm is reached they pull apart / expand and contact the housing which in turn starts spinning. Once again has screws to adjust force required to pull them apart.

 

[2000delux]

pic of the internals - it expands outwards towards the screws which have springs on them to adjust amount of force required.