A Different Mod....

Also had to use a belt sander on a sprocket to fit my nuvinci, was too thick a sprocket, if the metal doesn't get so hot you can't grab it for a moment then you aren't getting anywhere hot enough to destroy the temperament, it's like filing but slightly faster.
Okay, you've convinced me. :)
 
Yes I understand that you're only grinding the side, but heat spreads. I have just read this objection and not actually sure if I've read an actual account the experience, so I am just looking for real confirmation that it works well in practice. Have you put many miles on the thinned sprocket?
Well we turned it over in the hot summer and now it's almost Christmas, his large sprocket is not even on the radar and the tension looked good last I saw a week ago when we were prepping to turn a THIRD sprocket over and I even happen to suggest it today because he was mentioning changing his gearing a little for more top end.

I'm confident I could install it in my bike if I wanted and I'd have no problems, in fact I might need to since after 8 months mines beginning to look a bit more worn, could use a swap in a few months depending on how hard I use it. Lasting longer than the original did anyways so...
 
All my sprockets are turned down . And work fine .we heat hardened every thing at my work and the hard ness seems to penetrate at least 1 cm to even an inch into the steel .sometimes making it a real pain to cut a key way or drill set screw holes .all the ones in pic are turned down
 

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All my sprockets are turned down . And work fine .we heat hardened every thing at my work and the hard ness seems to penetrate at least 1 cm to even an inch into the steel .sometimes making it a real pain to cut a key way or drill set screw holes .all the ones in pic are turned down
Yeah that's perfect, I find that if you have a larger supply of fat bites you can turn them all down to what you eventually need chain wise.

They last as long as any other, or as above if you can re treat the metal then you have a great option. Remember we are not looking for lighter bicycles exactly. We are trying to make something reliable, and the extra weight is certainly worth it in this area.
 
Hi guys. I've been building my motorized build from the ground up...so to speak. I slapped a 79cc Predator on a 21-speed. I removed the crank, using the bottom bracket to build a jackshaft ( 5/8" shaft 9"L 5/8" presicion bearings [OD 1- 3/8"] meshed int the original ballbearings). NO PEDALING ALLOWED. All was going well until the last two steps - mounting the drive sprockets and drivetrain! Temporarily I wanted to power a gear mounted on the leftside rear wheel. Ultimately, I want to drive the bike gears. My problem is broken down into both short term and long term. The short term problem: The leftside 9 hole - 32 teeth, dished sprocket takes #415H chain but I can't find a 5/8" bore keyed sprocket to mount on the jackshaft.
The long term problem: I can't find any sprocket to mount on the right side that fits the multi-speed bike chain. I need help!

This 9-tooth sprocket will fit and be 4:1 gear ratio:
http://www.staton-inc.com/store/index.php?p=product&id=320

Combined with a 48t rear sprocket, that'd be 5.33:1 ratio.

If you want to drive the bike's gears, use these parts:

http://sickbikeparts.com/chainring-adapter/

http://sickbikeparts.com/chainring-freewheel-24-tooth/

This will chain to the rear cassette.
You won't need a freewheel, 'cause you don't intend to pedal.

For the left side, try this:
http://sickbikeparts.com/chainring-freewheel-52-tooth/

and this:
http://sickbikeparts.com/freewheel-spider-5-arm-110-mm/

also this:
http://sickbikeparts.com/chainring-adapter/

Sadly, for either left or right-side chain drive,
the gear ratios will still be numerically low.

Methinks you'll need a torque converter along with
the gears and sprockets to make this work.

On this forum, there have been many ways how
other members have done their install.

Good luck.
 
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I think the OP wanted to remove the pedals entirely. He must have a pull start.
What's with all the zombie thread resurrection lately anyway? :p
Incidentally I did have a go at making a kit 10t fit a #410 chain the other day and it went well I think. I will have no hesitation grinding it down even narrower to fit multi speed chain. :)
 
Also you can turn down a gear on a keyed shaft to fit thinner chains, done it twice. Put the gear on a drive shaft of the right size and make it spin under motor power. Then run an angle grinder along the teeth and body of the gear untill the chain fits well. Take it very slow at first and lightly feel out the danger zone with the angles of contact you can make, some work nicely and others try to rip the grinder from your hand. That being said wear your damn goggles!
I did it a similar but different way. I have a bench grinder and a small dremel-ish rotary tool, and I knocked the 10t engine sprocket onto a bamboo cane so I could rotate it easily and steadily, and not burn my fingers when using the bench grinder or chop them off when using the cutting disc on the rotary tool. :)
 
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