Rear sprocket bolts Qingqi QM200GY-BA

[forchetto]

Thank you for your comments. Have you done a tour of the forum yet?. There are quite a few bits and pieces concerning our bikes here.

Also, I've just found out the reference number for an equivalent sprocket from JT Sprockets, reference nº JTR 809.44 . Put that reference in the buyers guide search box that appears and it goes straight to the right sprocket:

http://www.jtsprockets.com/61+M54a708de802.0.html

The Suzuki bolt only just fitted in the hub. Before you do the final fitting, run the screws into the holes to ensure they will fit without bottoming and no metal has to be removed to accomodate the plain shank section.

The dimensions of the drillings on the Qingqi's hub are as follows:

Overall depth of hole 32 mm
Depth not threaded 7 mm
Depth threaded 15-17 mm

If you find the bolts bottom out due to the unthreaded shank touching the start of the thread you may have to remove one or two of the first threads in the hub with an 8.2 or 8.3 mm drill. There's plenty of thread left.

Just for the record, did you manage to retrieve the broken bolt?. I'm curious to know where about its length it sheared. This might confirm our findings. Also have a look at the remaining bolts to see if there's any sign of strain somewhere along their lengths. What tends to happen is that the sprocket moves slightly and, due to tolerances, not all screws take up the shear strain equally. One of them will do that first and that will be the one to shear first followed by the next one that touches the side and so on.