View Single Post
Old 05-20-2014, 09:23 AM
mapbike's Avatar
mapbike mapbike is offline
Motorized Bicycle Elite Member
Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: Speed & insane vibrations

Originally Posted by dylanr26 View Post
Yesterday on the way home from work I hit 32 (using gps so it was correct) on a completely stock china girl or whatever (44t sprocket) the vibrations were insane. Was it because it was revving at high rpms or because its a cheap huffy cranbrook beach cruiser?

I recently ordered a low profile air filter and a banana looking expansion chamber. Im thinking about a 36t sprocket (how fast will I go then?) But it feels like my bike will fall apart going faster then 32. Any bikes out there that handle speed well? I might just switch the engine onto another bike. Thanks
32 MPH with a 44T is pretty good, the vibes will be there no matter what bike you put that engine on, I have one bike that has an older engine I bought from an ebay vendor a few years back, it runs great and has good power but vibrates like crazy at above 32-34 MPH, I have a 36T sprocket on the bike and it works good for me on it.

If I had a 44T on that bike I'd be having the same results you are, a better flowing exhaust makes a noticeable difference on these little engines and if you go with a 36T on it you'll probably get 32-34 MPH fairly smooth and then the vibes will probably kick in above that speed if it does like mine.

I have another older bike build that has a 41T and it vibes pretty bad above 28 MPH that one will get an engine swap soon...

I have two other bikes that both have the Gen IV engines from thatsdax, these engines run the smoothest I have had, both bikes will hit 43-45 MPH and they dont have the severe vibe issue that the older ebay bought engines have.

most if not all of your vibration problem is because of an untrue and badly balanced crankshaft which is common for most of the china girl engines, Neil aka (motorbicycleracing) & Thats Dax sells a better balanced engine that doesn't have the serious vibration issue that many or most of the other engines have, I bought three lowers from thats dax and have two of them built up and running, working on the third soon, these engines will give you great speed and good power without the horrible vibes if you ever decide you want an engine that runs smoother, my bikes cruise at 40+ MPH with 36T tooth sprocket.

I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
Reply With Quote