410 help

[scooter]

Need some help guys, have had the 410r since May and seems like problem after problem. I followed the oople build thread and that made it seem better. The problems are a funny vibration at low rpm that I can't seem to locate. I've changed all the bearings twice and tried rebuilding the diff's a few times with different shimming following the TD tech tips, as well as two diff motors. The second problem is that running 7 min is a challenge without overheating. I run a tekin Rs Pro with a Novak 6.5 geared 19 or 20 pinion and stock spur. Got some advice from tekin but still no real luck. Any help would be appreciated before I give up and get rid of it, Thanks Tom