New engine, rattles hard and loud!

C

CodaBrink

New Member
I just bought a new engine for my bike, and it's fine until you hit 22 mph. anything above that, and it begins to rattle like it's going to explode! It's loud, it vibrates so hard that it makes riding uncomfortable. I know this can't be normal. It's coming from the engine, and when I squeeze the clutch, but keep the engine running, I hear the noise and vibration spin down. But once I release that lever, and the engine goes back into gear, it goes crazy again. What's going on? :(
 
There are many things that will cause and engine to run and sound rough. Here's a few questions:
1. Is the engine mounted solid or in rubber? Good contact in the engine mounts to the bike frame and all fasteners tight.
2. Is the rear sprocket concentric with the hub? ie, no wobbles or out of round conditions.
3. What rear sprocket size are you running? The larger the sprocket, the higher the rpms and the more chance of vibration.
4. Chain alignment and tension good?
Check these and get back to us. Also keep in mind that these are not motorcycles designed and engineered for a smooth ride. They are essentially novelty/hobby things that were never intended for anything but fun. It will never go down the road like a Harley or a Honda. It's a motorized bicycle.
Tom
 
I'd place my bets on the rear sproket or something to do with chain alignment/tension, since removing the drive system (pulling the clutch) solves the issue.
 
Pulling the clutch solves the problem.....check your pressure plate and ect. behind the right cover....I'll bet it has a horrible amount of run out.
 
It's not the chain, I had my brother listen for the sound when I had the clutch pulled, and it's coming straight from where the big gear meets the little gear, or around that area. It's coming from inside of the engine.
I described the problem incorrectly earlier. When I am going down hill, and I have the clutch squeezed, and I let the engine die, the loud rattling goes away. So it's not the chain..
 
I opened up the right side of the motor, the sound appears to be coming from the center of the motor. Like literally below the piston...
 
Heres some solutions: cut some pieces from a small rubber hose

Ringing noise from top of engine head = add rubber hose pieces between fins on head
silverware in a blender noise = add rubber hose pieces between fins on sides of engine
swirling screaching noises = add extra gasket or 2 to right side of clutch cover,also a ruber mat glued inside or outside of clutch cover helps cut noise too.
Buzzing noise like hundreds of bees = add hose to carb and make a air box

other vibration problems,check engine mounts and buy smaller rear sprocket.
 
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Is it like a high pitched bell-ish almost like a "CHING" kind of noise? Makes a difference if you hold the bike up and it's in gear or not?


I had that. Hard to tell where it comes from. I removed the clutch's front part (no puller needed) & put it back together with a heaver spring, and it seemed to have fixed it. Not sure where they sell the heaver springs at though. I got mine from a parts motor.
 
moronic_kaos: there's no difference between whether the engine has me on it, or if I'm just holding up the back wheel, or whether it's in gear or not. It always makes the sound unfortunately, and it always vibrates any time I rev the engine..
Yeah, I think I will be sending it back.. Something is wrong with the core part of the engine.
 
Good luck. I ordered from a store once with a 6 month part failure warranty. Turned out it wasn't covered after you already had your engine mounted. Hopefully you got it from a better place than I did.
 
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