Frustration! No one makes a sprocket that can be engaged and disengaged?

[Kartorbust]

Wish that 2 speed was designed with some sort of synchromesh, to make shifting gears much easier, rather than crashing into the next, or being near a dead stop.

Next best would be a 2 speed jackshaft as was stated before. You'd need this type of clutch on the engine http://www.bmikarts.com/Max-Torque-Dual-Sprocket-Clutch-for-Two-Speed-MiniBikes_p_732.html

They were common on minibikes, not so much on go karts...still it's doable, just may take up extra space for the jackshaft.

 

[itsid]

I wonder... if instead of synchromeshing and such it'd be possible to use "std" clutch plates...

If you can apply enough force with the selector a clutchplate can slip slightly before engaging right?
and once engaged.. it shouldn't be less "positively engaged" as the actual clutch itself, not?

Sooo, up to the drawing boards, clutch & pressure plate sandwich anyone?

'sid

 

[Kartorbust]

Is there anyone that is that knowledgeable on that? All I mainly do is take multiple designs and mash them into my own madness.

The other part would be to make it more compact, especially for say a sprint Kart, where you are very limited on room. Unless you could spread it out over a narrow area. I know his design was to be mounted at near 90 degrees and parallel to the engine, for the lack of backspacing between the engine and seat.

Lot of ways to skin a cat, I'm not a mechanical engineer, or at least mechanically inclined enough to figure out an "STD" clutch.

 

[NOBLNG]

A simplifiied version of what you are after would be a 2 speed manually shiftable jackshaft...

the jackshaft would have three sprockets on it. One sprocket would be keyed to the shaft and connected to the engine's clutch via chain.

The other two sprockets on the jackshaft would not be keyed to the shaft, instead they would be supported by ball bearings so they can freely spin. These two sprockets would be connected via chain to two sprockets on the rear axle. Different size sprocket combinations would offer different gear ratios.

Also on the jackshaft and positioned between the two freewheeling sprockets would be a collar that is keyed to the jackshaft. This collar would be able to slide axially back and forth. On each end of the collar would be 'dogs' that would engage identical dogs machined on the inside face of each sprocket.

A motorcycle shift lever or even a bicycle shifter could be used to shift the collar and engage one of the two sprockets at a time. Or neither sprocket if you wanted to be in neutral.

No way to avoid making those custom sprockets and shift collar.

Of course the type of clutch used on the engine would be important.

My BobCat Snowblower has this type of 2 speed transmission in it. The same mechanism is used for forward-reverse.

 

[bob58o]

I found it....
You find the weirdest stuff on Craigslist Vatican City.
JK, best of luck. I'm waiting on an update on a thread called "I want a two speed clutch" or similar.

I almost forgot about that one.

 

[bob58o]

This is what I was talking about..
http://www.diygokarts.com/vb/showthread.php?t=32273&page=3

"This engine will not have a recoil starter or a cooling fan, I am converting this engine over to free air cooling in order to keep the overall engine size small, I will replace the needle bearing that is in the clutch with a one way needle bearing clutch so that the mini bike can be bump started and I will have a compression release lever on the handle bar so that the engine will turn over easily while the bike is being bump started, also another benefit of using the one way needle bearing in the clutch is that the engine will brake the mini bike positively when the throttle is let off, but when the mini bike is stopped the one way needle clutch bearing will be over ran by the rotating inner bearing race that is coupled up to the crankshaft so the mini bike will stand still at a idle and then when the engine rpm increases the clutch shoes will engage in the clutch drum and then in turn rotate the drive chain."

"One can see here in these photos the clutch torn down along with the one way needle bearing (sitting on the clutch drum) which I have installed in place of the stock needle bearing in the clutch drum, I installed the one way bearing in the clutch drum using 638 Loctite Retaining Compound to aid the press fit of the one way clutch, the arrow on the clutch indicates the direction of lock up. With the centrifugal clutch assembled with the one way needle clutch installed in place of the stock needle bearing the clutch now as indicated with the arrows works differently, when the sprocket along with the clutch drum is rotated counterclockwise the needle bearing clutch locks down on the inner bearing race of the clutch which in turn rotates the inner drive hub of the centrifugal clutch which is connected to the engines PTO shaft therefore the engine turns over. If the clutch drum becomes stationary and the engine is running the inner drive hub and shoes will rotate freely as indicated by the arrows and when the clutch shoes engage into the clutch drum the entire clutch rotates together as one assembly."

---------- Post added at 12:10 PM ---------- Previous post was at 12:06 PM ----------

A jackshaft with a series of clutches (modified with One-way bearings), each set to engage at different RPMS (based of springs and weights). Each clutch would have another corresponding sprocket.
Was thinking a TC is much simpler and cheaper, if you still can't shift manually,

 

[chancer]

I found it....
You find the weirdest stuff on Craigslist Vatican City.
JK, best of luck. .

Just DO NOT go to the personals section

 

[Joe-405]

you need a transmission from a walk behind mower that has different speeds.............

 

[Kartorbust]

you need a transmission from a walk behind mower that has different speeds.............

Like the Peerless 700, but they are getting harder to find and cannot be shift on the fly, unless you want to blow out the gears. Sure they are used by those who race lawn tractors, but they are still not rated for shifting on the fly. That would be like taking a SM465 or similar transmission and not using the clutch to shift into first/low gear and grinding your way in. Those gears are not helical cut, nor synchored.

 

[Joe-405]

No. I mean a walk behind mower that you adjust on the fly like a new Honda or a older troy built walk behind. I work at a lawn mower shop. They adjust on the fly just fine.

 

[chancer]

I think he wants more of a run like Carl Lewis behind Mower!

 

[Kartorbust]

Never seen one like that. The only self propelled mowers I've had was an old commercial Snapper with a belt drive and then a Craftsman with a gear/belt drive. Neither one could be adjusted though.

---------- Post added at 11:14 PM ---------- Previous post was at 11:10 PM ----------

I think he wants more of a run like Carl Lewis behind Mower!

Might as well have Usain Bolt at that point lol