4 G question

Discussion in '4-Stroke Engines' started by dougsr.874, Sep 14, 2015.

  1. dougsr.874

    dougsr.874 Active Member

    Still can't find a 4G kit...Gasbikes has a 7G kit but from researching I learned that it will NOT freewheel, and this is a feature I want...I have a new drivesprocket from a 4G kit....question is :::can I use the free wheel sprocket from a 4G kit on a 7G kit.....Is the 7G kit any good other than that....????????/

  2. bikejock

    bikejock Member

    You can try your luck at phantom bikes. They use 4G kits on their bikes & sell the kits as well. I got mine from bicycle engines but they are now out of stock. You could give the 7G a try as I hear it's very similar to the 4G. Problem is they are all cheap China parts. I learned that the hard way when my 4G clutch bell broke after 100 miles.

    But if I were you, I would try a Staton inc. friction kit if your bike could fit one. Thinking of getting one for my mountain bike. They seem to use good parts & good engines. They use Subaru & Honda engines. Problem is their engines only seem to go up to 40cc but I'm sure at least one of their mounts could fit a 49cc 4 stroke. Ask them about the mount I'm sure they could measure the bolt pattern on their mounts for you.
  3. KCvale

    KCvale Motorized Bicycle Vendor

    What 4G version do you have?

    One 4G and 7G is for a Honda 50 or HS 142FG with no clutch and a long shaft output.
    The transfer case frame has a big hole where the clutch goes and the clutch bell rides on a bushing.

    The other is for the 142/144F-1G and has a short output shaft with the clutch attached.
    It is a complete unit with the clutch bell on a dual bearing shaft so the whole transfer case can go on and come off without touching the belt.

    They are not compatible.
    Well, you can cut down a long shaft engines output and mount a clutch to change an FG to an F-1G but it's not friendly to do and you can't go the other way.

    I don't have a 7G in front of me but it is like a 5/8" or maybe 15mm output shaft for a fixed sprocket.
    The 4G has a much thinner output shaft, like 14 or 13mm so not freewheel compatible sprockets.

    The 7G is junk but you may be able to find a freewheel sprocket to fit it.
    Keep the bushing well lubed and it might last until the output bearings go.

    If you have an HS 142F-1G 'tapered shaft' engine with clutch attached you are in luck however.

    The 2015 4G's I carry have a much larger freewheel bearing in the big pulley so you can use a small solid output sprocket and still freewheel pedal before it has to turn the belt and clutch.
  4. bikejock

    bikejock Member

    Would there be a way to eliminate that clicking sound the sprocket makes in pedal mode on a 4G? Sounds like it might be hard on the bearing & I would want pedaling to be quieter.
  5. KCvale

    KCvale Motorized Bicycle Vendor

    Again, which 4G?
    A clicking sound is the pawls inside like a ratchet wrench.
    Ever hear a quite ratchet wrench?
  6. bikejock

    bikejock Member

    Not sure which 4G kit but it's the one that came with my engine that was manufactured in September 2014.

    Guess a silent freewheel sprocket is out of reach. But to reduce noise & wear when pedaling I might get one of those freewheel drive sprockets for my rear wheel & find a way to prevent the motor chain from moving with my rear wheel. It's one of those sprockets where two pins go in so the motor drives the rear wheel & you remove the pins to pedal freely without any resistance or wear on any transmission parts. Forgot what they were called but they are built in Australia.
  7. KCvale

    KCvale Motorized Bicycle Vendor

    I have seen them but not tried one.

    Freewheels wear when the pawls engage to drive the sprocket.
    This is what typically fails as you just can't fit many of them inside a sprocket.
    When you are pedaling they just flip around happy with no force on them.

    That is why I like a big freewheel inside the big pulley and a solid output sprocket.
    It has bigger pawls and more of them so they tend to last longer, quieter too, it inside the transfer case cover.

    It still has that little chain drag, but it doesn't have to spin the belt.
  8. bikejock

    bikejock Member

    I'm considering one of your 2015 4Gs if I stick with my HS142 engine. Just wish the clutch bells were bolted on instead of welded on. I had my 4 clutch bell broke because of how it's welded onto the shaft. KC, do you do repair work on 4G kits? I need the 6002RS bearings installed on the clutch bell shaft. I have a new clutch bell & the two bearings but I don't have good tools to install them. I even tried thermal expansion & that didn't even work. Local places don't seem to want to touch the thing because of the clutch bell.
  9. KCvale

    KCvale Motorized Bicycle Vendor

    That was actually addressed with the re-design of the 2015 4G, the bell is one with the shaft now.


    I take new 4G's and make them long shaft 10G's so yes, I can rebuild/repair them and have a small supply of the 2 different bearing sizes.

    All you really need is a bearing press and some jigs to press the right thing into the right spot in the right order without screwing with anything else.


    Are you local?
    Give me a shout and come by with your parts, I'll fix you up for a beer ;-}

    Not local?
    Contact me in E about that as these 4G's are pretty easy to refurbish and still be like new if not better.
  10. bikejock

    bikejock Member

    I'm in California so I'll have to send you the parts. I'll be in touch.
  11. KCvale

    KCvale Motorized Bicycle Vendor

    I'll be here bike jock.