The first time started my Huasheng 142f 49cc 4 stroke motorized bike, it ran perfectly just like I wanted to, the idle was super smooth and very quiet. But when I actually used it vibrated A LOT. I did some research online about it but I found nothing helpful that could answer my problem. Now tho it idles terribly it goes up and down, it's quite loud, and vibrates the sh!t out of the bike. When I go slow it gets smoother but any faster than slow it has EXTREME amounts of vibration. Seriously tho like if you ride it for 10 seconds your whole body will feel in pain. I don't understand why it vibrates soooo much, I checked to see if it was the clutch, chain, chain tensioner... But that was not the problem. I tried adjusting the valves to be .004 intake and .006 exhaust and that changed nothing. I checked the carb and it's fine. I tried adjusting the carb and that just makes it worse or only very slightly better. I am quite disappointed with this 4 stroke engine as the reason why I bought it was because it was supposed to be "smooth", "quiet", "efficient", "low vibration" but it is none of those things. My 2 stroke feels like a Rolls Royce compared to this thing.
Does anyone know what the issue could be?
Thanks in advance.
What kit or clutch are you using? The 49cc is not a real torque machine and will shutter on acceleration until it is up to speed.
Check to make sure the clutch facings are not glazed and have oil on them. Putting a mushroom bearing on the output
shaft on a 49cc can sling oil onto the surfaces of the clutch facings. We need to know what transmission is on the 49cc.
I had similar problems on the kit from GasBike which was the "Ghost Racer" kit years back and last year I got tired of the
shudder in when I took off on the bike. This bike has over 5k miles on it and it has the same kit on it without any parts
replacement. Make sure the pineapple pressed brass bushing is free of oil after soaking the bearing over night. The heat
from running the engine and the clutches get hot and will let the oil sling out on the clutch.
What I did to fix the problem was to dry the clutch facings out using lacquer thinner or brake cleaner then spray the clutch
facings with a spray on graphite. This will let it slip a little but will still let the clutches get friction to drive the bell on the
transmission. Graphite is used on the CVT clutch on the "Death Row" CVT transmission so it does work and my 49cc
has never exhibited that shutter or vibration from the transmission over the last 1 1/2 years. Important You have to
maintain this transmission every few months especially making sure the pineapple bearing is lubricated.
The transmission is ok but is not the best on this little engine. A 36-tooth rear sprocket is a little too high a ratio driving
26" wheels so it takes a lot of torque to get a bike moving which generates a lot of heat on the clutch assembly. There
are more reliable transmissions available but they will cost you and are more than the cost of the entire motorized bike kit.
