We've had two of the XP2.0st bikes for about 18 months and love them. Great machines in nearly every respect, but as noted on this forum before there seems to be a "buzzing" rattle that comes from behind the rider at a certain speed when the motor is under load. I've traced it to a sympathetic vibration in the metal rear fender and suggested that perhaps putting o-rings on the mounting screws would help isolate the fender from the frame.
Because getting access to one of the fender mounting screws would require removing the rear wheel, I first began my investigation by removing the forward mounting screw, easily accessed at the inside of the fender at the very front. Nope, buzzing still very obvious at about 12mph (calibrated speed, not stock; the unadjusted XP speedo is considerably off).
Then I removed the two screws securing the rear of the fender to the wire bail. That did it--no more buzzing. So the motor vibrations were being transmitted to the rear fender via that wire bail.
The solution was to re-mount the wire bail to the fender after first inserting some sort of cushion. I found that a small piece of closed-cell foam did the trick. No more buzzing throughout the entire range. There is still, of course, the motor noise from the gear reduction inside the hub.
My piece of foam was torn from a hollow foam tube you can buy at the hardware store that is used to wrap around exposed water pipes to keep them from freezing in the winter. Each dark grey tube is about four feet long and very inexpensive. In addition you will need two new screws, since the original stainless screws are only about 1/4" long. The new ones are perhaps 3/8" long and the thread is probably metric; I didn't check as I found them in my workshop plastic bin of accumulated screws. The photos show before and after. The white fender is the original mounting and the black fender shows the foam insert.
Great machines and now silent! Life is good.
Because getting access to one of the fender mounting screws would require removing the rear wheel, I first began my investigation by removing the forward mounting screw, easily accessed at the inside of the fender at the very front. Nope, buzzing still very obvious at about 12mph (calibrated speed, not stock; the unadjusted XP speedo is considerably off).
Then I removed the two screws securing the rear of the fender to the wire bail. That did it--no more buzzing. So the motor vibrations were being transmitted to the rear fender via that wire bail.
The solution was to re-mount the wire bail to the fender after first inserting some sort of cushion. I found that a small piece of closed-cell foam did the trick. No more buzzing throughout the entire range. There is still, of course, the motor noise from the gear reduction inside the hub.
My piece of foam was torn from a hollow foam tube you can buy at the hardware store that is used to wrap around exposed water pipes to keep them from freezing in the winter. Each dark grey tube is about four feet long and very inexpensive. In addition you will need two new screws, since the original stainless screws are only about 1/4" long. The new ones are perhaps 3/8" long and the thread is probably metric; I didn't check as I found them in my workshop plastic bin of accumulated screws. The photos show before and after. The white fender is the original mounting and the black fender shows the foam insert.
Great machines and now silent! Life is good.
