Can a maxtorque bushing type clutch be made to freewheel/converted to one way

Discussion in '4-Stroke Engines' started by butterbean, Sep 5, 2015.

  1. butterbean

    butterbean Well-Known Member

    79cc predator, maxtorque ss clutch with bronze bushing

    I know several people have made different types of modifications to centrifugal clutches, but idk if anything is possible for the SS clutch. I tried googling, but maybe I'm not using the right terms, every time I tried it gave me a bunch of results on torque converters. If what I want can't be done, please don't flame me. Also please do not comment on how bushing clutches are junk, its simply not going to be helpful. I'm looking for simple, helpful yes/no/how answers, not trying to go running down rabbit holes. So here is my question.

    Can a bushing type clutch be modified or converted in any way, such as converted to a one way or be modified in such a way to pedal start? I remember reading on the other forum of a member modifying a centrifugal clutch (not sure which clutch or engine) to be able to pedal start, but don't remember reading how. If anyone knows how or can provide a link to the thread I'm referring to if they know, that would be great. I also remember that a member of the other forum, cobrafreak, created a bearing conversion mod, but don't know if its applicable to this type of clutch. If anyone knows and could tell me, that would be great. Just looking for any helpful info. Thanks.

  2. jbcruisin

    jbcruisin Member

    all the EZ clutches have a one way bearing so you can pedal start them.
  3. butterbean

    butterbean Well-Known Member

    Yeah but afaik those are special made just for the ezm for the qmatic. My maxtorque clutch is chain drive, so I'm not sure the one way bearing will fit or even where to get it.
  4. jbcruisin

    jbcruisin Member

    I was wrong. It's the max torque clutches Quenton makes for the Whizzers that have the one way bearing not the EZ's.
  5. butterbean

    butterbean Well-Known Member

    Ah, I see
  6. KCvale

    KCvale Motorized Bicycle Vendor


    A centrifugal clutch is a one way device.

    The power output spins a set of shoes that spread out and grab the inside of a bell with RPM's to transfer power.
    You can spin the bell all you want but it won't grab the clutch shoes and go the other way.
  7. butterbean

    butterbean Well-Known Member

    ?????? Never heard of needle bearings or sprag bearings? They allow the drum to propel the bike forward when the shoes grab, but freewheel when the rpms drop below the engagement speed, thus no engine braking. The cent clutches in the two stroke engines have sprag bearings and some comet clutches have needle bearings. The only reason I didn't buy a clutch with a needle bearing in it is because they come with 12t sprockets, not 11t which would throw off my gear ratio. Your comment seems to assume that what I want is a clutch that will engage spinning in reverse. To be frank, that's just dumb. When pedal starting, the clutch is still spinning the same direction. Idk where you got the idea that I was trying to spin the clutch the other way. What I am basically looking for is a way to make my clutch freewheel when disengaged, so as to eliminate the engine braking. I might not have explained that in my first post, but jbcruisin understood exactly what I meant. Pedal start would be nice, but I mainly want to eliminate engine braking.
  8. KCvale

    KCvale Motorized Bicycle Vendor

    No, what you want is the fixed size clutch bell to somehow engage your engines clutch pads pedaling with the engine off so you can pedal start it. That is the dumb part.

    Only the clutch shoes can transfer power in a cent clutch.
    To do what you want, you need an entirely different automatic clutch system I have never heard of, or just go with a manual lever clutch and friction plate like 2-strokes do.

    It is the same principle as a car with an automatic tranny, you can't bump start them like you can a manual either which is exactly why a 2-stroke with a cent clutch needs a pull start.
  9. butterbean

    butterbean Well-Known Member

    Clutches with one way bearings can be pedal started. There was also a guy on the other forum as I mentioned in my op who took a non pedal start clutch and modified it to engage when pedaling. I just don't know which clutch it was or how he did it. But as I expressed above and you conveniently ignored when quoting me, what I really want is a clutch that will freewheel to eliminate engine braking and yes, those do exist. How big is the rock you've been living under?
  10. butterbean

    butterbean Well-Known Member

    Not what I am looking for at all. If you don't understand the question, don't answer. Better to remain silent and be thought a fool, than to open ones mouth and remove all doubt.
  11. butterbean

    butterbean Well-Known Member

    Whether pull starting or bump starting, both the shoes and the drum would still spin the same direction.
  12. KCvale

    KCvale Motorized Bicycle Vendor

    The freewheel clutch's you speak of are for a manual friction plate clutch like 2-strokes have.

    Yes you can put a freewheel there and it will coast drag free and still bump start, that is because your back wheel is going to a manual clutch plate controlled by your clutch lever.

    4-strokes come with centrifugal clutches, which is what this topic in the 4-stroke forum is about correct?

    This is a 4G 4-stroke centrifugal clutch system.


    It only does 1 thing, it provides a power transfer between a fixed stationary bell based on input RPM of the source.

    When enough rpm centrifugal force spinning pivoting pads with springs pulling them in is enough spread them out enough to grab the inside of the bell, they connect and then spin together.
    Lower the rpm's and they disengage again and the bell freewheels.

    Now, in order to bump start that 4-stroke system you need to pedal up the sprocket from the back wheel, which connects to what?

    The clutch bell that is between your back wheel sprocket and the engine.

    It doesn't matter which way you turn that bell, how fast, or it having a freewheel somewhere, that bell simply will not grab the engines stationary retracted clutch pads and turn the engine over.

    I hope that helps you understand my short and accurate NO answer bud as I am not picking fights, just answering questions with facts.

    Now if you just want say a 7G to freewheel before it has to go all the way through the drive train to the clutch and freewheel with no drag, you use a freewheel output sprocket on the transfer case.

    Regardless, on a cent clutch, it only has one power input side and the output side is a 'both directions' freewheel.
    Last edited: Sep 18, 2015
  13. butterbean

    butterbean Well-Known Member

    You clearly still do not understand what I am saying. You keep repeating the same crap. Going back and forth and repeating the same crap is not going to make us understand each other. Please stop.
  14. butterbean

    butterbean Well-Known Member

    What I am trying to say on the subject of freewheeling is this. I know from my own experience as well as researching on the web, bushing type clutches do not freewheel instantly. That's why you get engine braking with them. Even when you let off the throttle, there is still friction between the bushing and the part of the drum that moves the chain. This is a well known and documented occurrence. Needle bearings instantly release, because they are true one-way bearings. And there have been modifications performed on some bushing type clutches, I just can't find any info by googling. I am going to post a thread on a minibike forum about it. I am hopeful that there may be a needle bearing or ball bearing conversion that I can do, i just have not found the right information yet.
    Last edited: Sep 19, 2015
  15. butterbean

    butterbean Well-Known Member

  16. KCvale

    KCvale Motorized Bicycle Vendor

    I think I finally see what you are looking to do!

    The clutch bell is on the engine shaft on a bushing along with the clutch itself keyed in like the Honda 4G or 7G, and not like the 4G 142F-1G with short shaft and clutch attached, which is completely independent.

    You want the bell itself to be able to spin the engine to bump start without having to engage the clutch at all by using a 1-way bearing to mount the bell to the shaft.

    Interesting idea and cool 'forward thinking'.
    Mechanically that can certainly work too.

    I suppose that could come in handy if you broke your pull rope or something.

    I have moved most of my MB build business to 4-stroke because I don't want to do a workout every time I start it, and they come with pull starters.

    I did try making a bearing option for the bushing in a 7G a year ago.
    Results here:

    Not at all worth the effort.

    The main purpose of this is to give your belt system two pulleys on multiple good bearings.

    The clutch bell is trying not to add friction to the system at idle when it is always being pulled tight at an angle by the belt tension.

    Come up with a new clutch bell with bearings design that will fit and see what happens.
    It would certainly make all long shaft 4-stroke engines an equal choice transfer case wise.
  17. butterbean

    butterbean Well-Known Member

    Actually bump starting would be a bonus if it happens at all. What I want is to eliminate the friction between the bushing and the clutch and hopefully eliminate the engine braking by doing so.
  18. KCvale

    KCvale Motorized Bicycle Vendor

    You must have a 7G as their only freewheel is the clutch bell.
    4G's either have a freewheel in the secondary pulley or a freewheel sprocket output so wheel motion never even makes it to the belt let alone the clutch bell.

    As mentioned I gave it a try and it was a waste of time and money so I haven't bought one since and rate them 'junk'.

    All I can suggest is you measure the output shaft and see if you can find a freewheel sprocket to fit it.
  19. HeadSmess

    HeadSmess Well-Known Member

    while at the local hobby shop i picked up a hirobo (?) heli starter bearing in the specials bin. about a 12mm ID from memory, possibly larger.

    all i know is that as they get larger...they get more expensive!

    normal lil nitro starters are 6mm and useless, OS tends for an 8mm...still pretty useless.

    you start looking at SKF bearing site and you can get pretty big ones. with hexes as options. cost a fortune...

    but you get to the point where its better to go to a place that does...

    torque convertors ;)

    because the centre member of a torque convertor is mounted on a big fat one way bearing. sprag clutch. freebies?

    you wont get bump start.

    easier to mount the freewheel in the rear sprocket so you dont have to spin the chain either.

    just the clutch bell and chain is a brake in itself... it becomes a step up gearbox in reverse.
  20. butterbean

    butterbean Well-Known Member

    Since when have you ever heard of a maxtorque clutch on a kit transmission? This is for a 79cc predator with jackshaft plate. The clutch is on the crankshaft. Engine braking occurs in bushing clutches because after you let off the throttle, there is still friction between the bushing and the drum. You're supposed to be some kind of expert or something.