Post by piperrode on Aug 27, 2007 18:08:23 GMT -5
I have a 2006 Tank 250DE with the CFMoto engine which just passed the 3000km mark. Sunday I set out to change oil and other fluids and change the drive belt to Kevlar (Thank you Stan for your timely shipping !! )
As I settled down for the oil change, I noticed that the front, upper muffler support bolt was missing. Further investigation revealed that it had broken off (%^&&#%@(!) even with the face of the flange on the motor. What was most distressing, was that the two front muffler bolts are also the bolts that connect the rear axle frame member to the motor, hence to the rest of the bike and I had been riding for some indeterminate time with half my axle frame not attached.
Replacing the bolt was a trip to the local hardware (flanged metric size 8x1.25 approx. 2 3/8" long) followed by an hour of patient screw extraction.
It was when I started reassembly that I realized what had caused the bolt to break was likely common to many other CFMoto 250 bikes and constituted, what I believe to be a potentially dangerous situation for riders.
The holes in the front end of the axle frame member are drilled way too large for the size of the bolt used to attach them to the motor. This allows the axle frame to pound on those bolts with a shearing force every time the rear wheel hits a bump. Keeping the bolts tight enough so that friction between the components prevents movement is unlikely. There are no lock washers or locking serrations on the bolts. I suggest anyone with the CFMoto 250 inspect these bolts regularly.
As a quasi-fix to the danger of recurrence, I fashioned two bushings from a piece of copper tubing (1/4"id / 3/8"od) that now snug up the frame holes to the bolts. Not as good as a proper steel bushing, but they should work for now.
I don't know if my broken bolt was from bad Chinese steel in the bolt or the pounding of the moving frame. I also don't know if the oversized holes in the frame (one of which had already started to wear into an oval) were a manufacturing technique to make alignment easier and speed assembly or if the holes were simply sloppy design.
The most important thing I don't know is how many other scooter brands and models this problem may affect. So I suggest that if you own a scoot with the CFMoto 250 (244 for the nit pickers) engine that you check the two front muffler bolts for tightness and wear as soon as you can. It would also be good to post the results of your inspection as a possible guide for others.
Dave
As I settled down for the oil change, I noticed that the front, upper muffler support bolt was missing. Further investigation revealed that it had broken off (%^&&#%@(!) even with the face of the flange on the motor. What was most distressing, was that the two front muffler bolts are also the bolts that connect the rear axle frame member to the motor, hence to the rest of the bike and I had been riding for some indeterminate time with half my axle frame not attached.
Replacing the bolt was a trip to the local hardware (flanged metric size 8x1.25 approx. 2 3/8" long) followed by an hour of patient screw extraction.
It was when I started reassembly that I realized what had caused the bolt to break was likely common to many other CFMoto 250 bikes and constituted, what I believe to be a potentially dangerous situation for riders.
The holes in the front end of the axle frame member are drilled way too large for the size of the bolt used to attach them to the motor. This allows the axle frame to pound on those bolts with a shearing force every time the rear wheel hits a bump. Keeping the bolts tight enough so that friction between the components prevents movement is unlikely. There are no lock washers or locking serrations on the bolts. I suggest anyone with the CFMoto 250 inspect these bolts regularly.
As a quasi-fix to the danger of recurrence, I fashioned two bushings from a piece of copper tubing (1/4"id / 3/8"od) that now snug up the frame holes to the bolts. Not as good as a proper steel bushing, but they should work for now.
I don't know if my broken bolt was from bad Chinese steel in the bolt or the pounding of the moving frame. I also don't know if the oversized holes in the frame (one of which had already started to wear into an oval) were a manufacturing technique to make alignment easier and speed assembly or if the holes were simply sloppy design.
The most important thing I don't know is how many other scooter brands and models this problem may affect. So I suggest that if you own a scoot with the CFMoto 250 (244 for the nit pickers) engine that you check the two front muffler bolts for tightness and wear as soon as you can. It would also be good to post the results of your inspection as a possible guide for others.
Dave