Poor acceleration and massive vibes



Hey guys I've been trying to get my StingrayXL with KingsMB "80"cc engine back on the road. Everything is tracking smooth and it started up after a year with no problems within 10 feet. It idles fine and has enough power to make its own way up some pretty steep hills without pedaling. The problem I'm having that I haven't been able to figure out is the engine has a hard time accelerating after about 15mph and vibrates like theres no tomorrow. The engine even gets louder in the mid rpm's with how much it vibrates. It does this under load and with no load at all. When I'm going down a hill it still has a difficult time accelerating but smooths out a little bit once it gets up to speed. Not by much though. I checked my plug and its a nice chocolate brown so I know I'm not running rich or lean. I'm running the recommended 30:1 fuel mix. I have a boost bottle installed but it doesn't seem to make a difference in poor performance if I block it off or not. Any ideas? The spark plug is new. Checked to see if the exhaust was clogged which it isn't. Cleaned the air filter and carb. It's definitely getting enough fuel. If I choke it and give it gas it dies so no intake leak. This engine has probably about 1000 miles on it so its definitely broken in. Any ideas fellas? I really want to get this thing running well so my paps can go on some MB rides with me. Thanks in advance.
i would say the something has moved to induce a vibration. a place to start is the clutch, then drive gear. 1000mis its time to put your hand on everything that moves. good luck mitch
i think you need to start with the clutch and adding some grease into the clutch gear and bearing .
Same thing.

SirJake, I have the same identical thing happening to me. My engine only vibrates when I reach about 15 MPH and stops when I accelerate to 17 mph. It goes smoothly from there. I found a link on some nice motor mounts using springs that may help you. http://motoredbikes.com/showthread.php?t=12512
I can't use the spring motor mounts because of how my engine is strapped to my bike. I'm going to put a piece of rubber (from a car tire specifically) to see if that works. Someone suggested that rubber from a car tire may be too hard?? Who knows...if it works I will post.

I too purchsed the boost bottle (haven't gotten it yet) hoping that it will smooth out the ride. I did put in a new plug (NGH B8HS) and it's running better at top speed.