Mounting a 79cc Greyhound in place of 49cc HS 142?

Discussion in '4-Stroke Engines' started by Pete Lawrence, Mar 22, 2013.

  1. Pete Lawrence

    Pete Lawrence New Member

    So, my HS 142 recently called the quits, i cant work out whats happened this time, it just pulls and doesnt go. Anyway, it got me thinking about a larger engine, and the 79 seems ideal, but, would i be able to mount this engine in place of the HS 142? If i were to just take the old engine off, drill some new holes and bolt the new one in, would all the fuel lines, electrics/throttle still be any use? Or would i need to replace these too? Any other issues that im missing?

    - Thanks all

  2. darwin

    darwin Well-Known Member

    What type of setup do you have? Inframe, rear rack or? Your HS might not be done yet. Is it getting spark, fuel? Maybe we can figure it out. Those HS 142fs are tough little motors.
  3. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    The 79 CC HF motor will normally fit on the HS motor mount, however it must be mounted forward [cylinder tilts to the rear] and to the right [towards the bicycle chain side].

    You can use the throttle control system, you will just have to figure a way to connect to carburetor [we have tested lots of the 79 & 99 CC HF motors with our drive systems including the Greyhound series].

    If you have a Q-Matic drive on your HS 142, you can simply re-drill the mounting plate install a larger primary pulley, and change the sping in the clutch.

    Another item that will require a major modification is the exhaust system, as it is mounted straight up and must be moved or removed and replaced.

    Have fun,
  4. Rudystork

    Rudystork New Member

    Hey Darwin, I've also got the 142 four stroke, I've been using it daily since December 15th.
    I'm starting to have issues starting I use the choke on full initially but only for a sec, as when it starts I have to move choke to half way the back to full repeatedly.
    I also have to give the it the gas just a Tad in oder to get bike to idle. Is there a idle screw on the Carb? Even after a good 5-9 minute warm up, I still have trouble keeping the engine running at a stop, have to use throttle and brake.
    Any insight would be greatly appreciated.
    South Carolina
  5. darwin

    darwin Well-Known Member

    Rudy you should start your own thread, some people take offense to hijacking anothers thread. You can use you cable barrel adjuster to increase idle, or use the idle screw stop adjustment on the carb to increase the idle. Looking at the carb rotate your throttle and see the screw where the butterfly shaft stops on, that's what needs to be adjusted.
  6. Rudystork

    Rudystork New Member

    T.Y. Darwin. I'm gonna do just that, hey Ptete sorry for just jumping in like that.
    Gonna take old Darwin's advice and post one myself.
  7. Pete Lawrence

    Pete Lawrence New Member

    No problems, i worked out the issue with my current engine (loss of compression because of stuffed piston ring) and i think ill just order in another HS 142. As a student in VCE i dont have time for much screwing around with drives etc like i did when i made the bike... :(