This is the fifth in a series entitled WHAT MAKES IT WORK? In this episode, I show the inside of a CENTRIFUGAL CLUTCH and how it works. Watch all the videos in this series.
Awesome! This brings back so many memories! I put probably 10,000 miles on a go cart with one of these clutches. Well before I could drive a car I was plying the county roads with this vehicle.It would indeed make a "chime" or "jingle" noise at idle. That was the way they were!I got tired of paying all that money for an entire clutch when that brass bushing would fail. So; I had a local machine shop make me about 5 spares. That was more economical than buying clutches!
+mrpete222 Yes it was! I think I remember seeing three remaining spares last year, in a very dusty cardboard box, with a sagging lid.... somewhere at my mom and dad's place. Like all boys, I eventually changed from go carts to cars and never looked back!
Thanks for showing us the principle of the centrifugal clutch. I have never seen one taken apart before, so as usual, I learned something new from your videos'.
Great video. When at high speed, my vibrating plate compactors power has just started dropping right off back to idle after only 5-10 mins of use. After some google searching on why this could be happening, I have come to the conclusion that it is down to what I now know to be the centrifugal clutch, & that the pads are no longer able to grip the outer drum, through either lack of tension from the springs, or simply wear to the pads. Your very informative video breakdown on the mechanics of these clutches is where it really clicked that this is very likely the cause of my issue. I have yet to remove the clutch, but from what I have learned from this, is that I very likely need a new clutch, or a very good condition 2nd hand replacement, as I don't see that these can be adjusted to compensate the lose of tension in any way. Thanks greatly from the UK
From the first time I heard of these, as a kid 40+ years ago, I always thought they were the neatest design ever. Not perfect for everything, of course, but remarkably simple and effective. And it never occurred to me that they're almost identical to a drum-brake design. So cool to realize that.
Thank you Mr Pete for bringing back fond memories from my childhood. I would have loved to see this video back then to know how our clutch worked. Fun times.
Very interesting and informative. I suggested a centrifugal clutch to someone on the HSM forum who was having trouble running a compressor from a marginally powered generator. I think it would work pretty well. The other way to implement a clutch is with a tensioner on the V-belt, so you could start the motor unloaded, perhaps even with a flywheel, and then engage the drive to overcome start-up torque.
Once had a moped with that type of clutch on it.It was OK until it rained,then it would slip so had to pedal it to keep going. Liked your setup for the demo and was surprised to see how well engineered they were.Thanks again for another interesting video.
I'm really not sure how I started watching this channel, but I am so so glad I did. thank you Mr Pete, I've always had interest in mechanical things, and your method of explanation is great. keep it up
Hey Mr. Pete I've been around since dirt and this is the first time I have seen one of these clutches apart. Great video, and enjoyed it very much. Thanks again...Ken
Hey Mr.Pete I had an uncle that worked for Fairbanks's and Morse who were a big manufacturer of these clutches and other things back before and after the war and when he found out my brother and his friends all had mini-bikes and go karts he came for a visit and brought a wooden box with about Fifty different used clutches in it... being that we had a machine shop why it was kind of a right if passage to rebuild a clutch for your go-cart/ mini-bikes. in our neighborhood.... turning a drum or making a new bronze bearing ... my clutch on my minibike had needle bearings and a zerk to grease it only ever had to change shoes or springs had a "D" bore in the drive drum to change sprockets to any gear ratio you'd want.... Ahh the good old day's......
When I was 10, dad was going to make me a go-cart. He got a 5hp Briggs engine, 4 wheels and 4 shock absorbers. That's as far as he got - I'm still waiting for him to complete it. He passed away in 1999 !
This brings back memories. When I was a kid most mini bikes had a broken clutch and throttle. A boys fix to the clutch was to drill a hole in the outer housing and put a screw in the hole to bund up with the clutch and make it a full time clutch. For the throttle, we would put a string on the carb and pull on the string to go faster. I actually never saw a mini bike without a jury rigged string pull trotted when I was a kid. Chris
I noticed when fully engaged the pivoting wedge on the driving shaft would wedge the friction shoe out onto the driven drum so under high speed and a bit of torque it would hold tighter. More torque, more wedging out for tighter fit. I seem to remember they would release at a lower speed than they engaged. I had the chain drive 3.5 and 5 hp B&S engines on mini bikes and go karts. And for awhile we had a centrifugal clutch and belt driven torque converter on one of those beach trikes from the '70s. I think the 6 wheel amphibious atv's had the same torque converter and clutch.
Mr Pete-Remember the Cushmans that had the 2 speed transmission? They had a centrifugal clutch that had a clutch pedal that released the clutch so you could shift gears. Your mention of Cushmans brings back many memories both good and painful!! Marv. W
+marv w I used to have a Cushman with a 3 speed tranny and 2 speed gearbox that also had 2 wheel drive. A flexible cable drove the front wheel geared hub. Rokon now makes them. The ubiquitous Honda 90, trail and street, used a centrifugal/ manual clutch that disengaged when the shifter was operated. Many smaller motorcycles also use them. www.rokon.com/
+Moholo 88 P.S. I agree with the memories. I remember my 38 Dodge sedan had a torque converter and a clutch pedal. Some Volkswagens and the aircraft tugs I used in the service had a t/c and an electric clutch. I imagine there are many other examples and configurations.
Great video. I learned, as a kid, that the lawn mower shop would sell different strength springs so the clutch would engage sooner (lighter). This sure made the launch quicker in a go-kart. The different springs were $2.00. Wonder what ever happened to that neat old go-kart?
Ahh, you could have had some fun with that. Having lubricated the main bearing in it and reassembled without the spring and remounted in the lathe - you could have demonstrated the clutch action at much lower lathe RPM !
So I watch this, and then an episode of Jay Leno's Garage comes out with gas powered bicycles and what do they talk about? Centrifugal clutches. Pretty cool!
On my minibike, I would lock the clutch by jamming a nickel between the drum and the shoe. Then I could push start it and after it got started, the vibration would make the nickel fall out.
The basic operation is simple and easy to understand. The clever bits no one will generally notice - and that's how the brake material is driven with the pin through the slot towards the centre. The interface shape can be quite critical to effect fancy functions - typically, when load is added, extra pressure is applied pressing the linings against the drum - to give a more positive action between slip and grip. One RU-vidr, HubNut, has an 'Invercar'. Yes it has a centrifugal clutch then power's transmitted through a pair of automatic 'Reeves drives' to effect a constantly variable transmission. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-j2jkyCaard0.html What effectively these pulleys turn out to be are two analogue computers fighting over a drive belt ! The one on the engine side is a centrifugally controlled pulley - the faster the engine spins, the more belt it wants to take (to keep engine speed down). The wheel side pulley contains a tensioning spring to keep the belt tight and some torque measuring ramps - the clever bit. If the torque is high, it prevents the ratio changing. So as the engine loses the torque, that allows the ratio to change - perhaps if you reduce the throttle opening on the engine or its power peters off at high rpm. I think they fit a restrictor to the inlet manifold as a means of capping top rpm. Gearbox ratio is all 'calculated' mechanically to suit the driving conditions. I think it's ingenious !
I got a cheepie ebay clutch for my grandson's go kart, about 30$. Not good for the HFT 6hp motor, it was destroyed in less than a month. So I ordered the "extreme" clutch for 50$, claim it is good up to 12hp. Should get it next week. I have a vd of it. He likes to goose the gas. Gotta learn to floor it, LOL. I'd like to make a heat sink for it, that old one got hot, I had to shorten that spring and lower the idle rpm to make that cheepie work. Don
+Mickey Xtian It's just a tube into an artery for fksake. It's all the rage nowadays, like getting your tonsils out in the 50's. By the way, it's spelled "grateful"
Sorry, I must have mistaken the purpose of a "balloon catheter" in relation to heart surgery. Got to admit it would be funny if it were about the other thing. :)
Great information here. I wonder how such a clutch can be "burned". On my chainsaw, as you say, there is such a clutch, but I had to change it because I burned it. I don't know how it can be done. Is this a common problem with this kind of apparatus? As always please accept my sincere and warm regards.
+Robert Patoine Either more power than the clutch was designed for (unlikely, unless you modified the chainsaw), or partial throttle (letting the clutch slip under power). With these clutches it is best to either be idling or going at full throttle. Do you ALWAYS pull the trigger all the way? Or do you try to cut slowly (perhaps for extra control)?
+Peter W. Meek Thanks, I did indeed cut slowly. But now I pull the trigger all the way only when I am ready to cut and very near the tree. And I release it immediately after. Thanks
Now that I think about it, I guess a simple centrifugal clutch would cause too many performance problems for todays world. LOL! It would still work with a reduction, but it may cause slower acceleration and poor performance. Thanks for the articles!
Wouldn't some high temp. grease be much better than oil for that bearing? Are these kind still made? So you can rebuild this kind, wouldn't you want to scuff the contact area of the clutch/brake pad material w/ some course sand paper?
a slightly more modern version: www.mopedspeed.dk/images/products/sa2240_2_b.jpg the way the shoes are hinged they "snap on" and grap harder and harder the more torque is transfered
+Gary C i am aware of that, I am curious if the lugs help. They seemed to move and were notched. So when they slightly twist is they would push the pads
+Gary C i am aware of that, I am curious if the lugs help. They seemed to move and were notched. So when they slightly twist is they would push the pads
