Centrifugal Anyone ever used the Centrifugal Clutch Kit?

Discussion in 'Transmission / Drivetrain' started by unraw, Dec 31, 2008.

  1. unraw

    unraw Member

  2. arceeguy

    arceeguy Active Member

    I got one from Boygofast, and his kit had a one way roller clutch in the clutch bell so you could still pedal start the engine. I did not have to install the pullstart, but I did and haven't had any problems. You'll need to install wider cranks on your bike to clear the added equipment.
  3. unraw

    unraw Member

    Ok. I want to get it for my small bike which doesnt have peddles on it.

    Do all of them have a one way bearing?

    Attached Files:

  4. arceeguy

    arceeguy Active Member

    Apparently, some do and some don't.
    Problem is that most of the people selling them probably don't even know!
  5. QuadManiac

    QuadManiac Member

    The ones that DO know will have something like "starts by pedaling" in their ads.

    Have the centrifugal clutch, love it (from BoyGoFast). 250 miles so far with no probs... time will tell.

    As to the pull starter... had some problems, replaced the rope once. But I never need to use it anyway, except to start it when it's up on my bike stand.

    Normally, a turn or two on the pedals and she always starts right up cold. Just a bare push on the pedals when she's warmed up. Starting and stopping without using the manual clutch is real nice, and i assume the manual clutch will last just about forever now.

    Just as a warning - at about 25 miles, my cent clutch started slipping. I pulled the cover and saw that there was too much grease on the bearings which had migrated out to the clutch shoes. Cleaned that up and have had no problems since.

    Good Luck and Good Riding.
    Last edited: Jan 4, 2009
  6. iron_monkey

    iron_monkey Guest

    Ok, I have installed the kit.

    Installing was a pain, had to bore out the bushing abit so that clutch fits and the gears match. Otherwise the clutch cover cant even go on, and the gears may only touch/overlap alittle resulting in a bad metal crunching sound and not much power transferred to the wheels.

    With my 31T sprocket this thing is like a CVT, the engine appears to sit on 3000rpm a considerable proportion of the time (which means its slipping alot). Slight throttle will cause considerable vibration when the engine rpm is below ~3000 as the pads vibrate the clutch bell. Vibration goes after engagement rpm. Throttling only to moderate/high throttle (instead of slight) bypasses/eliminates this vibration as engine goes straight to ~3000. Sending Quadmaniac a PM to see if this is normal.

    Acceleration is worse than manual clutch and starting up a moderate/steep hill from a dead stop is not possible unless you want a dead clutch. Power transfer is very gradual and small, the clutch doesnt "grab" as I expect, which is disappointing as this means it spends alot of time slipping up to speed.

    Which is bad news, I dont think the pads will last long unless i replace the sprocket with a 44T.

    As for the benefits, its very user friendly, much more comfortable operation, and no more engine chugging below idle speeds. But in my case pedalling from a dead stop is still needed in many situations.
    Last edited by a moderator: Jan 9, 2009
  7. QuadManiac

    QuadManiac Member

    Unfortunately, I can't tell you about the 'add on kit'. I purchased my engine from BGF with both the centrifugal clutch and pull start installed ($169 + ship, if i recall).

    Other than the issue mentioned, i've had no trouble at all. No vibration, no strange noises. As a matter of fact, the standard noise issue (coming from gears between the crankshaft and standard clutch) are not an issue with my engine. The Cent clutch seems to block a significant amount of this noise (similar to why some ppl put sound dampening material on their clutch cover). In my case, the clutch cover, which is significantly beefier, doesn't vibrate like the stock one does.

    Another possible difference: I am using a Sick Bike Parts shift kit also, and always start out in 1st or 2nd on my 7 speed cassette. Clutch engagement is quick from a standstill, no slipping and no pedaling required. There is no slipping at all going thru the gears and in 7th on a mild hill with full throttle, there is no evidence of anything but full clutch engagement. I can climb the steepest hills in my area (pretty darn steep) at 8 to 10 mph in first with no pedalling and no clutch slipping.

    The SBP shift kit adds a freewheel to the crank assembly, so when i come off throttle the cent clutch disengages from the driveline quickly which causes both chains to stop turning. To shift gears while coasting, I simply blip the throttle to get the chains turning, and turn my grip shifter. Very simple, and works like a champ everytime.

    All i can say is, with my configuration, the centrifugal clutch works great! I can't tell you how long it will last because I only have about 300 miles on it so far... but even if it were to wear out soon, i'd buy new shoes and keep using it - it's so dang convenient.

    SO, bottom line.... With a Sick Bike Parts shift kit, the centrifugal clutch works like a dream (at least in my case) and the whole package is exactly what i was looking for in a motorized bike.

    Good Luck and Good Riding!
    Last edited: Jan 9, 2009
  8. unraw

    unraw Member

    sounds like with my 20" tire and a 44t sprocket, the CF clutch would work great! Now if I could afford it....
  9. iron_monkey

    iron_monkey Guest

    Yes a gearbox like the shift kit would change things considerably, as the torque required is lowered.

    At this point in time I wouldn't recommend the centrifugal clutch to heavy riders not using the shift kit or riders using small sprockets. There's only a certain amount of torque this clutch can transfer from a dead stop. Even pedalling to ~5km/h it slips too long for my liking.

    At speed however the clutch appears to work normally and can do hills at speed. Starting up the side of said hills from a dead stop, is where it cannot grab and constantly slips.

    Will take it apart again to see if oil has contaminated the clutch bell. Don't remember any previous period where the clutch performed better though.

    Can you give a rough guess what engagement rpm is yours Quadmaniac?
    Last edited by a moderator: Jan 9, 2009
  10. iron_monkey

    iron_monkey Guest

    Reverted back to 44T sprocket, and now the bike can go from a dead stop easily, even in a incline. Its safe to say one should stick to 40+T sprockets with a centrifugal.

    However the vibration(and associated sound) at low rpm/speed is still there, and its only a matter of time before something breaks from fatigue failure. The one way bearing seems to be sometimes giving way; although once engine is started its totally fine. The bike is still fully operational, I hope things don't go worse from here.

    Right now i dont recommend it due to the fact i had to spend alot of time grinding a part to make the clutch fit, and also the vibration. The other choices are a 4 stroke engine kit and the pre-assembled centrifugal 2 strokes - Quadmaniac's clutch appears to be good. As with these 2 stroke kits its all a gamble. Depending on the extra cost of the pre-assembled 2 stroke you may buy the 4 strokes instead.

    If you are going to buy a 4 stroke engine, you may as well buy a cheap Ebay 4/2 stroke scooter that can be road registered for ~$600. E.g. http://cgi.ebay.com/ebaymotors/Moto...id=p4506.c0.m245&_trkparms=65:2|39:1|240:1318
    Last edited by a moderator: Feb 3, 2009
  11. POPS

    POPS Member

    Do you have a 50cc as I read somewhere that the clutch kit doe's not fit the 50. Where did you buy your kit from? I don't understand why you had to do some grinding to get it to fit and the gears don't mesh right ? I bought mine from from Zoombicycles.com'80cc LTD,centrifugal and pull start kits. I have installed both and they went on like a charm. If you go to his sight and look at the kit under parts, click on it and a PFD install link is there. Mine installed just like that. No problems and no binding or mesh issues but I haven't road tested as of yet because it's still on my bench getting other MOD's but it turns smooth by hand. I will keep you all posted once I put it on the hill's...POPS
  12. Skyliner70cc

    Skyliner70cc Active Member

    I got a BGF kit. Many dented/dinged/damaged parts, no customer service, engine runs well and clutch kit works as advertised. Rope on pull starter broke on 6th pull.
  13. iron_monkey

    iron_monkey Guest

    I have a 60cc (not 50 or 66 or 70). What was the issue with the 50cc? Mine was that the clutch bushing wont go very far down the crankshaft if you dont increase the bushing inner diameter a little.

    Also it means the clutch itself wont go in properly and you cant even put the cover on.

    The vibration im guessing is due to the clutch pads not being totally centered in respect to the clutchbell and one of the pads having lower resistance than the rest; meaning at low rpm only pad is hitting only one area in the clutchbell.

    I didn't disassemble the inner clutch assembly to have a look at the pad levers/spring/etc, seems to be out of my depth. I have no idea where to start, and I think the spring would a real pain to put back on.
    Last edited by a moderator: Feb 4, 2009
  14. POPS

    POPS Member

    It is a tapered shaft and a tapered bushing. I wonder if it is possable that the bushing was on backwards? Did you check out Zooms install instructions? Mine went on like that with out a hitch... About the no fit 50cc issue I thing it was on the customers reviews for the product...POPS
  15. POPS

    POPS Member

    I had another thought about your dilemna. Did you know or perhaps forget to remove the half moon key in the crank??? That would explain everything you are discribing for problems. If the key is still in there pull it apart again,remove and reinstall. Hopefully everything will line up like it should...POPS:idea:
  16. iron_monkey

    iron_monkey Guest

    haha yes i did, I spent alot of time looking at the crank/bushing thinking what i have done wrong before resorting to drastic irreversible measures (grinding). Either its bad quality control (on the clutch or my engine) or its made for the 66cc version my importer sells.

    Bushing definitely wouldn't have gone backwards, that would have been physically impossible.

    edit: Well I know why its vibrating/making clanging noises at low rpm now. Looks like the clutch isnt engaging properly. I finally notice the diameter of the pad assembly/inner clutch changing erratically and this is evidently making the racket/vibration. It should slowly expand into the clutchbell for smooth engagement but it doesn't. Alot less serious then I thought as i thought it was the bearing.

    The fact that I dont know how to disassemble the inner clutch and the saying "if it aint broke don't fix it" I'd probably leave it alone.
    Last edited by a moderator: Feb 7, 2009
  17. POPS

    POPS Member

    Maybe it will smooth out as it breaks in . Keep us posted...POPS
  18. iron_monkey

    iron_monkey Guest

    clutch doesnt smooth out at all. Getting a new clutch since they're gone alot cheaper at my importer and see if things change.
  19. iron_monkey

    iron_monkey Guest

    Okay bought another clutch, since they become much cheaper from the same chinese ebay shop.

    This one was what my first clutch should have been. The bushing now has been pre-bored so it fits into the crankshaft properly, and more importantly the thing doesnt vibrate massively with a loud racket when it starts to engage.

    This one slips significantly more, but im guessing the pads need to be broken in (only used for 5 mins as of now).
  20. iron_monkey

    iron_monkey Guest

    There is no limit to the dodgeyness of these clutches. The gear had completely severed itself from the clutchbell after 10min of riding.

    Comparing this to the first clutch, the worker who built this one had appeared to put too little "adhesive"/soldering (silverish grey material that keeps them together) to this one.

    Now to find a glue/epoxy.