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shimpo rk-8 problems

updated sun 22 apr 01

 

andrea schuman on fri 20 apr 01


i have a shimpo rk-8 . my problem is that when i step on the pedal the wheel begins to thump the faster it goes the harder the thump. i had the rubber ring replace and after three months im having the same problem. the cone is metal and looks a little beaten but in not really sure what it should look like . i have only seen the rubber cones, should it look like that ? I would like to get a rubber cone put on but can i do it my self or does it have to go in a shop. i got the wheel cheap from my old high school and am glad i at least have one. i would like to try any thing befor i give up on it .


my other problem is that if i stop the pedal it springs back on and i have tried to ajust it but then its to losee and i cant get it to stay on high . its hard to explain. sorry .

any info would be great. its hard to find help for the rk-8 .

thanks

mud girl









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vince pitelka on sat 21 apr 01


> i have a shimpo rk-8 . my problem is that when i step on the pedal the
wheel begins to thump the faster it goes the harder the thump. i had the
rubber ring replace and after three months im having the same problem. the
cone is metal and looks a little beaten but in not really sure what it
should look like . i have only seen the rubber cones, should it look like
that ? I would like to get a rubber cone put on but can i do it my self or
does it have to go in a shop. i got the wheel cheap from my old high school
and am glad i at least have one. i would like to try any thing befor i give
up on it .

Dear Mud Girl -
I am not familiar with the pedal tension system on the RK-8, so you may have
to call
Shimpo on that problem. But regarding the THUMP THUMP THUMP THUMP THUMP,
that is ausually because of having left the drive engaged with the motor
turned off. When the drive cone is engaged with the rubber ring there is a
great deal of pressure between the two in order to maintain positive power
transmission. You must make absolutely sure to always leave the wheel
disengaged when you shut it off. If you leave the wheel engaged or
accidentally engage it for any period of time while it is shut off it can
leave a permanent "divet" in the rubber ring, so that it thumps on each
revolution. In some cases if you leave it running in gear for a few days
(won't hurt it a bit), it will work the divet out, and the problem will be
gone. If not, your only choice is to replace the rubber ring again and be
more careful about not leaving it engaged. On the faux-Shimpo I built, I
installed a microswitch and a loud buzzer, so that if I turn the power
switch off when the pedal is engaged, or accidentally engage the pedal while
the power switch is turned off, the buzzer gets my attention quick. In 20
years I have only replaced the rubber ring once, and have never had the
THUMP THUMP THUMP THUMP that characterizes so many old Shimpos.
Good luck -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/