Manual disengage for a centrifugal clutch

[janvos39]

Ptero can you find dimensions for this overrunning clutch. I could check if a design is possible in the centrifugal housing of the Burgman 400. I have the drive disassembled at this moment for building in my additional gearset , so I can easy make a drawing if I have the dimensions.

jan

[Ptero]

I don't have the specs for the one rated for 250cc. You wouldn't want to use that one anyway. It's too small.

I suggest one from this series. These look very tough, easy to disassemble and simple to machine to fit.
:: Dayton Superior Products ::

Choose Products/Clutches/Overrunning clutch

For the Burgman, the OR 100 Overrunning Clutch is rated at 100 ft/lb torque at 1000 rpm. The Burgman is rated at 44 ft/lb torque at 3400 rpm, so you'll be running with a factor of safety of about 3 which should be ideal to survive some sloppy speed matching without damage. My calculations show 960 rpm for the Burgman's 21-inch diameter rear tire at 60 mph, so it's right on the sweet spot.

The O.D. is 3 3/8-inch. The I.D. comes in 3 sizes that can be machined to the correct shaft size. Let me know what you think, looking at the teardown. I don't have any drawings for the Burgman but I bet there's a way to do this that's bulletproof.

[janvos39]

I took some dimensions and draw the situation of the centrifugal clutch. Somewhere between the purple and the red part the overrunning clutch has to find its place.I have to check how much area is available in the cover. dimensioning data wise looks OK . I go from the 3 3/8 inch OD and see if it can be made to fit.

[Christ]

Use a lighter spring on the clutch/drum assembly... that will let you go slower.

You can change the "stall speed" as it were, of the clutch assembly by messing with the spring and counter weights... lighten the weights, or stiffen the springs, and you have a "higher stall"... lower the spring rate, or make the counter weights heavier, and you have a "lower stall".

Something I used to do with go-karts after tuning them to run on Kerosene (less power, better efficiency).

[The Atomic Ass]

Originally Posted by Ptero

I don't have the specs for the one rated for 250cc. You wouldn't want to use that one anyway. It's too small.

I suggest one from this series. These look very tough, easy to disassemble and simple to machine to fit.
:: Dayton Superior Products ::

Choose Products/Clutches/Overrunning clutch

For the Burgman, the OR 100 Overrunning Clutch is rated at 100 ft/lb torque at 1000 rpm. The Burgman is rated at 44 ft/lb torque at 3400 rpm, so you'll be running with a factor of safety of about 3 which should be ideal to survive some sloppy speed matching without damage. My calculations show 960 rpm for the Burgman's 21-inch diameter rear tire at 60 mph, so it's right on the sweet spot.

The O.D. is 3 3/8-inch. The I.D. comes in 3 sizes that can be machined to the correct shaft size. Let me know what you think, looking at the teardown. I don't have any drawings for the Burgman but I bet there's a way to do this that's bulletproof.

You need to multiply road speed RPM by 6.168 to get RPM's for anything installed at the clutch drum, which seems to me the easiest place to put it. That gives us greater than 6K RPM for 60 mph.

Also, what kind of sloppy speed matching are we talking about? Jamming the throttle from idle? And I think you might be using a different year or model Burgman than either janvos or I as the 130/70-13 tire I have calculates out to 60 mph at just slightly OVER 1K RPM.

And the 44ft/lbs is flattering, but probably the crank output of the newer (2007 and up) model.

[The Atomic Ass]

Originally Posted by Christ

Use a lighter spring on the clutch/drum assembly... that will let you go slower.

You can change the "stall speed" as it were, of the clutch assembly by messing with the spring and counter weights... lighten the weights, or stiffen the springs, and you have a "higher stall"... lower the spring rate, or make the counter weights heavier, and you have a "lower stall".

Something I used to do with go-karts after tuning them to run on Kerosene (less power, better efficiency).

Although interesting, it's not something I'd want to attempt, at least not unless I go in the over-running clutch direction. A lower stall speed would essentially end all possible coasting. 15mph is slow enough as is.

[The Atomic Ass]

Originally Posted by janvos39

I took some dimensions and draw the situation of the centrifugal clutch. Somewhere between the purple and the red part the overrunning clutch has to find its place.I have to check how much area is available in the cover. dimensioning data wise looks OK . I go from the 3 3/8 inch OD and see if it can be made to fit.

Excellent drawing.

I was talking with my father earlier this afternoon about this while I had the clutch drum off. Once we get some dimensions plugged into that schematic we'll be in business.

What's better, Dayton Superior is only 20-30 miles from my house.

[Ptero]

What's better, Dayton Superior is only 20-30 miles from my house.

Wow. That is cool. Take them the clutch and run the idea by them. Let me know what they say.

It looks like you could cut out the center on a lathe, ream the inner bore of the sprag clutch to fit, attach and weld the splined section to the overrunning clutch, then weld the clutch (perfectly, with a jig and dial indicators) to the center.

But placing the sprag clutch at the engine instead of the rear hub changes the model of overrunning clutch you will need and keeps a lot of stuff spinning when you're coasting that shouldn't be. Definitely not the best approach imho.

[dcb]

Originally Posted by Ptero

...and keeps a lot of stuff spinning when you're coasting that shouldn't be...

For that matter one should look into putting the sprag in the rear hub as there are a couple gears to go through after the clutch output shaft I think.

Maybe one of those combination bearing/sprag thingies would be a good fit.

[The Atomic Ass]

Originally Posted by Ptero

Wow. That is cool. Take them the clutch and run the idea by them. Let me know what they say.

It looks like you could cut out the center on a lathe, ream the inner bore of the sprag clutch to fit, attach and weld the splined section to the overrunning clutch, then weld the clutch (perfectly, with a jig and dial indicators) to the center.

But placing the sprag clutch at the engine instead of the rear hub changes the model of overrunning clutch you will need and keeps a lot of stuff spinning when you're coasting that shouldn't be. Definitely not the best approach imho.

Actually, the spline is integrated into a plate, which is then riveted to the clutch drum. Build new plate with over-running clutch, punch off old plate, bolt or rivet new one on. Easy.

This would not be at the engine, though. The clutch is not on the engine in this bike. The only thing spinning is the rear tire, drive shaft, 1 fixed gear shaft and the clutch driven shaft with the clutch drum on the end of it. It really does spin rather freely, with some good gear oil in it.