Hub motor Kit

I bought a 36volt, 800 watt hub motor kit off of Amazon. Just got it installed today...on my initial trial run I was very disapointed to find that it seems the wheel or tire or something is out of round...it's kinda like riding a bucking horse...bumping up & down...I set the rear of the bike on jacks and had my son hold the throttle open....from several feet away I sat down to see if I could see the problem....I couldn't..it all looks like its running true but the bucking is still there.....Is the the tire????? anyone had a similar problem please let me know & how to correct it....the kit is installed correctly as this is not the first one I've built.

I'd have to see it to be sure but it could be a hard spot in the tire or a warped rim

Deflate and reinflate the tire a few times. If that doesn't help, take the wheel to a bike shop for trueing.

I had a bit of a bucking problem with my bike as well, and found part of it to be a stiff link in one of the jackshaft chains.