Sometimes you can't find exactly what you need for your MB and you just have to make it yourself. With a few basic tools and a little time thinking things through, you can make a component that meets your needs as well as a vendor supplied item. In my case, I needed to be able to easily swap sprockets on my jackshaft to change gear ratios. I had a standard 17 tooth sprocket with 5/8" bore that resulted in gearing that was too low for cruising. So, I purchased a keyed 5/8" steel collar with set screw and 1 1/8" reset ($4), a 3 1/4" diameter steel washer with 1 1/8" bore ($.89), five 5mm x .80mm hex head bolts (on hand), and a 24 tooth bolt on sprocket from Sick Bike Parts($5.95). Replacement sprockets are available from SBP up to 48 tooth. The first step was to dress the washer bore to a true 1 1/8" since the galvanized coating reduced it slightly. The second step was to carefully mark the 5 mounting holes on the washer. I used a chart in the Craftsman manual shown in the photo to determine that a 11/64 drill is appropriate for a 5mm x .80mm tap. Once the holes were drilled and tapped I removed the galvanized coating from the back of the washer and spot welded the washer to the collar. Locktite could be used to secure the mounting screws, but I will use locking nuts instead. This $11.00 adapter works great and gives me the flexibility I need to easily gear up or gear down.
Custom Made Sprocket Adapter
- Thread starter Scootmeister
- Start date
The sharing of ideas and successes on this forum is what I love about this place. Thanks for your post Scootmeister.
Great job! Not everyone has your skills though including me.
Affordable Go Karts sells this 5/8" adapter to add sprockets or a disc brake.
Only $8.25
I have to get a few for my 4 stroke builds.
Unfortunately the sprockets that they sell are for #35 chain except for
one sprocket that is used on the extended cranks for the bicycle chain.
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Thanks Nunyabidness, I have learned a lot from the forum as well. MBR, I have never used a #35 chain, but that's a good price for the adapter. I needed one that uses a wide range of 415 sprockets, so I just made one. Maybe your adapter could be drilled out to fit different sized sprockets as well. 
I never used 35 either and need to use 415 or 41 sprockets too!
It is going to need another plate adapter?
Great work, Scoot.
I really like it when necessity cultivates engineering like you've done here. Thanks for sharing your skills with the members.
Tom
I really like it when necessity cultivates engineering like you've done here. Thanks for sharing your skills with the members.
Tom
My pleasure, 2Door. Here are photos of the adapter installed on the jackshaft. I took the bike out for a spin and the higher gearing made it much more rideable. My speedo still isn't hooked up but I'm guessing my top end is about 30 now. The little Chinagirl hums like a sewing machine and I can actually feel the high speed jet kick in!!! I'm lucky I got a keeper.
