Engine is making a weird popcorn maker clatter sound.

[scootoe]

I started the 85 Spree up today and noticed the same thing as before last fall. I start to drive down the road and no problems. Decent , smooth accerleration etc. Once I meet full throttle , which is about 25 -29 MPH for my Spree. It periodically makes a Popcorn machine like clatter and I experience loss of power from the engine. After a little clattering its back to smooth running again. Than after a little while some more clattering and and power loss. Its driving me nuts! I just want the thing to run smooth again. The sound is not kick back from the muffler, it sounds like its comming directly from the piston case. Almost like if you were sitting on the scooter and looking down, the clattering is comming from the engine. I have cleaned the gas tank. I have cleaned the carburator and even installed an extra in line fuel filter between the tank and carb. I have read through the manuals and can't find what the issue is with my scooter? I had it running smooth and great all last summer up until the fall time when this intermittent clattering and power loss thing started after running full acceleration for a while. Has this happened to any one else? Were you able to fix it ? What can I due to fix it?

[vette76]

sounds like bearings. probably the one in between the piston and connecting rod. this should be replaced immediatly before u kill the piston, rings, and cylender if its not too late.(which i am going through right now).

[noiseguy]

I think you're refering to "4 stroking," which is where the scooter misses at every other fire. Usually does this at high RPMs. I believe that's caused by an overly rich mixture at wide open throttle... Read the plug chops section of Tech Docs.