making rattling noise over 24mph

will 3501 · #1 07-03-2009, 12:54 AM

I have a Grubee star fire 48cc with 200 miles on it There's alot of vibration noises between 22mph
and 30 mph but at 28mph between 32mph it smoothed out A distinct rattling at 24mph between 28mph Maybe im pushing the engine to hard but it seems like it wants to go faster and i dont think ive maxed the rpm s I like to ride about 20 to 22mph im always looking out for the boyz though passed by a few{cops} here in phoenix and they just waved at me. the one distinct rattling noise is definetly coming from engine area cause i let off the gas and it stops should i be concerned with this i havent lubed or greased the gearing except put a dab of grease on the clutch end when installed . ty Chill Will AZ

Bikeguy Joe · #2 07-03-2009, 05:47 AM

Sounds like typical piston slap.
Sometimes....the motor mounts will loosen and it sounds like detonation. Check those.

Cabinfever1977 · #3 07-03-2009, 12:24 PM

check your nuts they might be loose. rubber between your mounts and frame might help with vibration.

marioaz · #4 07-04-2009, 02:02 PM

One thing I've learned is that any rattle on the bike will sound like it's coming from the motor. Just saying.........

Junster · #5 07-05-2009, 02:11 AM

Mine does the exact same thing. It's the big clutch gear. Take off the right side clutch cover and put some (not alot) grease on the gear teeth. I use moly/graphite grease. I have readjusted the clutch several times and nothing stopped it. The greasing helps but I have about 1000 miles on my bike now and it's still there. If anyone has a real solution to this I'd really like to hear it. Is there any end play adjustment in the clutch shaft?