Update on the 4G T Belt drive transmission

Discussion in 'General Questions' started by ash, Sep 25, 2013.

  1. ash

    ash New Member

    Hello everyone. I'm setting out on my first build and I've been doing quite a bit of research on "What to buy". I'm interested in a four stroke 49cc HS kit. I'm trying to avoid the "hoot" trannies and a q-matic isn't in the budget just yet. So, the question is has the one way bearing problem been addressed in the latest 4G t-belt drive transmissions? Has anyone used a latter version of the gearbox? I'm looking at Bicycle-Engines website and they have them in stock. It seems everyone agrees that the G4 is better than the G5. Also, If there's already and answer to this question, I would be very very grateful to be steered to the right thread. Thanks!
    Last edited: Sep 25, 2013

  2. BigBlue

    BigBlue Active Member

    Don't waste your money on a 5G kit or a Stage III kit. The 4G is a decent 4 stroke kit. Bicycleengines.com is the importer for the Grubee kits. Many members install the 4G kits for customers.

    By the way, go to the introductions and introduce yourself to the forum community, out of common courtesy.

    Good Luck,

    AKA: BigBlue
  3. ash

    ash New Member

    Thanks for the info, I just posted an introduction.
  4. dougsr.874

    dougsr.874 Active Member

    I've said this before but guess it bears saying again. I have been using the SAME Stage 111 gearbox for over 5 years and it's proven faultless.....the secret is to fill the case with axle grease not oil.....I also have a 4G kit which is good also.....however, the clutch's that they started using bout a year ago are to light and tend to engage & disengage constantly at low rpm's....I will buy some of the old heavier clutches if anyone knows where I can find them...
  5. ash

    ash New Member

  6. Max-M

    Max-M Member

    Just want to put in my two cents regarding the EZ Motorbike Q-Matic drive: Unless you've completely ruled it out because of its price, I'd seriously look at the long-term, positive implications of going with a Q-Matic. With all of the little things that have gone wrong and driven me nuts on my two motorized bicycles over the years, the Q-Matic hasn't given me five seconds of trouble. It's bullet-proof, it looks good, and EZ Motorbikes owner Quenton Guenther and his organization are extremely helpful, truly nice people -- and real champions of our hobby.
    Last edited: Sep 26, 2013
  7. dougsr.874

    dougsr.874 Active Member

    DO NOT BUY from gas bikes or King's (same company I think)......Recommend using biycle-engines. com(birddog dist.)....may be a little more expensive but they will answer their phone & ship quickly.....
  8. ash

    ash New Member

    Thanks, I just confirmed with Bicycle-Engines that they sell the updated Grubee G4 T-belt kits. I'm seriously leaning toward just spending the money and going with EZM. Does anyone know what motor they ship with their Q-Matic kits?
  9. bikejock

    bikejock Member

    My 2014 Bicycle Engines 4G transmission broke within a month of use before I even broke in the engine all the way. My clutch bell snapped off the shaft while I was driving one day. A few weeks before that a pulley bolt unscrewed causing my belt to come off & get torn a little. The cause to the problem with my belt was due to the fact they don't use thread locker (which they really should) in the crucial parts like the bolts that hold the pulley wheels on the shafts. I don't know how some of you are getting so much reliability out of the 4G as some of you claim. I am still kind of a noob when it comes to 4 stroke kits though so I'm still learning.

    I have to be on the cheap as well when doing a build so I often don't have an extra $300 to throw down on a Qmatic drive ether as much as I would want a Qmatic. My only options are 2 stroke kits or budget 4 stroke kits for now because I typicaly keep a total budget on a bulld at about $500 to $600 at most including the bike (usually a used craigslist bike) engine kit & upgrades/mods. Oh & EZM ships a long shaft HS 49cc with their complete kits. Pretty much the same engine Bicycle Engines uses with their kits just with a long shaft instead of the tapered shaft. If you have the money go for the Qmatic. Some vendors have adapters that allow the Qmatic to work with a tapered shaft engine but it would cost you an extra $35 to $40.

    The clutch bell on my 4G broke off likely because of poor workmanship on Grubee's end & something I might have done wrong in the installation process. My motor must have not been perfectly aligned with my drive sprocket causing my transmission to turn unevenly against itself leading to the clutch bell failure. After examining the replacement clutch bell looks to be tack welded on to the shaft in two places which to me screams poor quality. Something like a clutch bell really should be bolted on with a good locknut as opposed to being tack welled on in such a flimzy way. Bicycle Engines is good about getting the stuff I need shipped & the customer service is better than other vendors though.
    Last edited: Jun 18, 2017
  10. CrazyDan

    CrazyDan Active Member

    A huge bonus to buying the ezm qmatic for a straight shaft, is when your lil engine finally dies or you get bored of it, you can swap it out for a 79cc or 99cc predator, bolts right up.
  11. bikejock

    bikejock Member

    I was actually thinking about going with a 79cc predator fir my next project.I would have to go with the $99 CNC transmission most vendors provide with the predator kits.