bakaneko
Well-Known Member
Hello. I thought I share what I did to "fix" or compensate for chain stretch in my GasBike transmission box. The chain in the GB transmission is very small and I think the BikeBerry one is small too but probably not as small. After normal use, the chain will stretch and might jump the drive sprockets in the transmission rendering the transmission useless. I think I am probably the only HS-142F rider with the lowest price chain transmission box so not sure how relevant this is to other HS-142F riders, but to compensate for the chain stretch I bolted in a chain guide to the bottom portion of the drive chain that also moderately increases tension.
The chain guide consists of a steel bolt, nuts, spacer, and washers. A 2 inch bolt with no threads (until the end) is the drive shaft with the two spacers being the chain guide and a spacer being the bearing. These are offset using nuts so that the guide portion is aligned with the drive sprockets. There is about 1/8" play for the chain in the chain guide. I drilled a hole into the transmission to place the chain guide with low chain tension. The nuts, spacers, washers diameter is slightly larger than the bolt. And, all material is stainless steel.
This has been working well for almost 200 miles and there is some additional noise due to the spinning washers I think. The spacer as a bearing is okay, but it would have been better with a stainless steel ball bearing. Problem is the cost for those bearings are around $10 and the transmission is $50 new. This setup cost me $5. I put a bunch of high temp grease inside the transmission. Not the prettiest fix, but I don't have great tools and yeah its a $50 transmission.
Here is a simple diagram and pictures of it. Yup, my bike is a dirty mofo.
The chain guide consists of a steel bolt, nuts, spacer, and washers. A 2 inch bolt with no threads (until the end) is the drive shaft with the two spacers being the chain guide and a spacer being the bearing. These are offset using nuts so that the guide portion is aligned with the drive sprockets. There is about 1/8" play for the chain in the chain guide. I drilled a hole into the transmission to place the chain guide with low chain tension. The nuts, spacers, washers diameter is slightly larger than the bolt. And, all material is stainless steel.
This has been working well for almost 200 miles and there is some additional noise due to the spinning washers I think. The spacer as a bearing is okay, but it would have been better with a stainless steel ball bearing. Problem is the cost for those bearings are around $10 and the transmission is $50 new. This setup cost me $5. I put a bunch of high temp grease inside the transmission. Not the prettiest fix, but I don't have great tools and yeah its a $50 transmission.
Here is a simple diagram and pictures of it. Yup, my bike is a dirty mofo.
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