don grubee asked me to post this on the 4g
[GruBee inc Field Service Bulletin: # 3
4G.bmp
Subject: 4G T Belt Transmission-
Model: 2010 model year HuaSheng 142F 49cc 4 cycle engine kits with one-way bearing.
Problem: The first 550 pcs. of model 2010 4G Kits with 80T driven pulleys shipped in 2010
may have early one-way bearing failures. This has been brought to our attention both in
Australia and in the USA. Corrective action denoted below:
. Our ride testing in China is a bit hampered in that it is against the law here to ride a motorized bicycle on
the city streets. Something the free-world has trouble understanding.
. Our 2 day ride test at an abandoned airport of the initial one-way bearing having 7 sprags and 9 balls
and plastic seals showed no failures, however some customers soon told us that within 2 weeks or less a
bearing failure can happen. This is unacceptable and we went to work to correct the problem.
. It took 90 days to get failure data of the root cause due to having no failed samples and to poor technical
communication from the field particularly from Australia.
. As soon as we confirmed the failure mode we asked all WD's to hold off selling any of their 2010 4G
stock until a correction could be found. Unfortunately; I don't think many of them stopped selling.
Solution: As of the 2011 model year all of our 4G 4 cycle T Belt Transmission kits with the
one-way bearing option will have a new and improved 28 Sprag HD one-way bearing in the
80T driven pulley. This new bearing design has twice the lock torque ability of the first design.
. If you have the early 2010 model year 4G one-way bearing kit please contact your selling WD for a free
HD brg. replacement. You can quickly see the difference as the early design has 2 plastic seals and the
new 2011 HD bearing has 2 metal seals.
. All 4G WD;s have been sent 5 of new style HD one-way bearings last month for their approval and sign
off test. As of Jan. 10, 2011 we are awaiting those responses. When WD approved we will ship free
replacements to each of them. 200 go to Australia and 350 go to the USA.
. WD's should have new stock within 90 days. To install you will need to properly press the new bearing
in the pulley cavity on the outside race and on the inside race when going on the shaft. Do not
hammer the bearing in place; use an arbor press with a guide.
. In addition to the new improved one-way bearing introduction this year we also have a robust 12T
Heavy-Duty freewheel drive sprocket which can replace the old 11T freewheel design found on
2009 model year 4G kits having 100T driven pulleys. This new item likewise should be available at
WD's within 90 to 120 days providing they all send orders for them.
. We regret any inconvenience this may have caused anyone.
. We do stand behind our product but sometimes corrective action takes a while in China.
Good luck and happy trails: China GAS / Gru-Bee inc.
[GruBee inc Field Service Bulletin: # 3
4G.bmp
Subject: 4G T Belt Transmission-
Model: 2010 model year HuaSheng 142F 49cc 4 cycle engine kits with one-way bearing.
Problem: The first 550 pcs. of model 2010 4G Kits with 80T driven pulleys shipped in 2010
may have early one-way bearing failures. This has been brought to our attention both in
Australia and in the USA. Corrective action denoted below:
. Our ride testing in China is a bit hampered in that it is against the law here to ride a motorized bicycle on
the city streets. Something the free-world has trouble understanding.
. Our 2 day ride test at an abandoned airport of the initial one-way bearing having 7 sprags and 9 balls
and plastic seals showed no failures, however some customers soon told us that within 2 weeks or less a
bearing failure can happen. This is unacceptable and we went to work to correct the problem.
. It took 90 days to get failure data of the root cause due to having no failed samples and to poor technical
communication from the field particularly from Australia.
. As soon as we confirmed the failure mode we asked all WD's to hold off selling any of their 2010 4G
stock until a correction could be found. Unfortunately; I don't think many of them stopped selling.
Solution: As of the 2011 model year all of our 4G 4 cycle T Belt Transmission kits with the
one-way bearing option will have a new and improved 28 Sprag HD one-way bearing in the
80T driven pulley. This new bearing design has twice the lock torque ability of the first design.
. If you have the early 2010 model year 4G one-way bearing kit please contact your selling WD for a free
HD brg. replacement. You can quickly see the difference as the early design has 2 plastic seals and the
new 2011 HD bearing has 2 metal seals.
. All 4G WD;s have been sent 5 of new style HD one-way bearings last month for their approval and sign
off test. As of Jan. 10, 2011 we are awaiting those responses. When WD approved we will ship free
replacements to each of them. 200 go to Australia and 350 go to the USA.
. WD's should have new stock within 90 days. To install you will need to properly press the new bearing
in the pulley cavity on the outside race and on the inside race when going on the shaft. Do not
hammer the bearing in place; use an arbor press with a guide.
. In addition to the new improved one-way bearing introduction this year we also have a robust 12T
Heavy-Duty freewheel drive sprocket which can replace the old 11T freewheel design found on
2009 model year 4G kits having 100T driven pulleys. This new item likewise should be available at
WD's within 90 to 120 days providing they all send orders for them.
. We regret any inconvenience this may have caused anyone.
. We do stand behind our product but sometimes corrective action takes a while in China.
Good luck and happy trails: China GAS / Gru-Bee inc.
