robin eho35 mounted at HT location

Discussion in 'Frame Mounted Engines' started by mbatl, Oct 9, 2011.

  1. mbatl

    mbatl Member

    Would there be any problems with mounting the reliable robin engine at the same location as the HT/china engine/80cc by welding the same size sprocket as the HT engine to the centrifugal clutch of the robin to utilize the sbp shift kit and gears?

    The robin engine turns the wrong direction to use as a right side drive, so I would have to use it as a left side drive with the use of a jackshaft.

  2. wheelbender6

    wheelbender6 Well-Known Member

    Sounds like a lot of work, but possible. I have seen a Honda GX35 mounted in the frame.
  3. 5-7HEAVEN

    5-7HEAVEN Active Member

    You could center-mount the engine, then run the jackshafts and sprockets. The big problem is gearing the engine low enough to utilize the cassette gears effectively. You might need 25:! gear ratio BEFORE it multiplies with the rear sprockets.

    My Tanaka 47R engine is center-mounted and runs thru a shift kit and rear cassette gears. What makes it most effective is its 5:1 pocket bike transmission. The gear ratio is 31.8:1 BEFORE reaching the rear sprockets. By the time it reaches 8th gear, final drive reduces to 12:1.

    The HT engine has a 4.15:1 internal gear. Without a step-down transmission, you will prolly need to use 8mm or #25 sprockets on the jackshaft and chainring sprockets. These sprockets are smaller in diameter, and can be used to create effective gear ratios at the cassette.
  4. mbatl

    mbatl Member

    Indeed. I forgot about the internal HT gear. After realizing I would need to mount the robin engine, buy a transmission for the correct ratios and a proper jackshaft, I think I may just sell both the shift kit HT and my robin friction drive so I can move on to a scooter. Another real issue is after all the work I do to the bike, I'll still be bound to 30mph and the far right side of the road at the end of the day. Taking the lane and riding at 35mph+ would draw alot of attention eventually here in Atlanta's various suburbs!
    Last edited: Oct 9, 2011
  5. 5-7HEAVEN

    5-7HEAVEN Active Member

    If I had to limit speeds to 30mph on my MB, I'd ride my Honda 150cc scooter too (The MB is more fun).

    I could get by @ 30mph on most streets, but on the ones w/35mph speed limits, the cars would try to nudge me off towards the curb.:ack2: