66/80cc Engine crankshaft is really tight.

Discussion in '2-Stroke Engines' started by Aligring, Apr 28, 2016.

  1. Aligring

    Aligring New Member

    I got a new 66/80cc bicycle engine kit the other day (eBay). I inspected the crack shaft after taking off the barrel housing and the crankshaft is SO tight. It very difficult to move the piston up and down. Is their a way to loosen things up? I gave the engine a test drive and the entire engine was crazy hot. The clutch housing, magneto housing, I mean the hole engine was so hot you couldn't touch anything on it. I'm not very familiar with the insides of these little engines. Any thoughts on the matter would be most appreciated thanks.

  2. justakid108

    justakid108 New Member

    I have the same problem... take off the head and put some motor oil in/ around the piston. It might be that it's too tight...
  3. crassius

    crassius Well-Known Member

    yeah, first step is to take out piston and see if crank is tight, if crank turns well, then check cylinder & piston for good fit and smooth surfaces (polish with 1200 grit sand paper if needed)

    also, a couple times out of several hundred motors, I've seen rings too big - file ends just a bit if needed