I bought a Dragstar 1100 Trike which I've put a lot of time and money into but I get a massive tank slapper at low speed. Pulling away is fine if I'm getting up speed and slowing down is fine until I get below 15mph then I have to grip tight which stops the slapping. When cornering at any speed I get a kind of scraping, grinding sound. I'm mechanically minded engine and electrical wise but this has me beat. The seals on the forks are good, I've had the tyres off the rear end and checked, balanced up and re valved, they're new tyres. The front tyres not that old and in good shape. There's no play in the steering at all and everything is tight.
Any ideas on what could be the cause please, as I said it's beaten me?
Thanks........