One more Shanghai shop to recommend is Shanghai Qiyi Motorcycle Accessories Ltd
上海骑翼摩托车用品有限公司
It's at 513 Wenshui Lu (may be Wenshui East Road) up in Hongkou District.
虹口区汶水路513号

Simon Wang aka Wang Anyun (王俺云) is the proprietor with his wife, speaks only a little English.
+86 21 5538 6591 x608
+86 130 6268 8803

They are good people -- very knowledgeable -- and serious riders.
good luck