Chain help

[Rickus Dickus]

I am building a new rear end assembly for my wife's Roadstar and going to chain drive. If anyone has experience with chains, what would an 18t drive with a 36t driven sprocket do for us? And if you could give me an idea of the chain length it would assure me I calculated it right. Going with the above sprockets and a 530 by 130 "O" ring chain. I will machine any adapters to fit the chain sprockets for the bike. This last motorcycle trip we had to buy ANOTHER drive belt at $300. I figured out why the belts keep breaking, but still want a chain drive for if one fails, I'll have a spare with some master links ready to go. No disassembly required to install the new chain.

[Gorilla]

I am building a new rear end assembly for my wife's Roadstar and going to chain drive. If anyone has experience with chains, what would an 18t drive with a 36t driven sprocket do for us? And if you could give me an idea of the chain length it would assure me I calculated it right. Going with the above sprockets and a 530 by 130 "O" ring chain. I will machine any adapters to fit the chain sprockets for the bike. This last motorcycle trip we had to buy ANOTHER drive belt at $300. I figured out why the belts keep breaking, but still want a chain drive for if one fails, I'll have a spare with some master links ready to go. No disassembly required to install the new chain.

Hugh I missed what the cause of the belt breaking was. Can you please re-advise. TU

[Rickus Dickus]

Sorry for not getting a reply sooner. Boils down to geometry. The rear axle does NOT remain a fixed distance from the drive pulley. Drawing a line from the center of the drive pulley to the center of the axle shows the swingarm pivot point is above that line so as the swingarm pivots up on bumps, the distance from the drive pulley to the rear axle actually increases. Adjusting the belt to the recommended slack didn't allow it to "stretch" to the longer distance. I added more slack trying to prevent the belt from being snapped at that point, but when we ride on some of these horrible roads in Louisiana there are times when our bikes actually get pushed into the air unloading the suspension, increasing the belt slack, in turn allowing it to ride up on the sides of the pulleys for a moment, then as the bike settles down it repeats the entire cycle again. A couple of friends and I put the bike on tall jack stands, worked the suspension up and down, cranked the engine to spin the tires, watched everything in action, lived to discuss it, and came up with this theory. Why it kept happening even when riding it with the typical two wheel set up and worse when I converted to a trike, we don't understand. Now I have converted it to chain drive (I know about the required maintenance) and have a chain tensioner on the bottom section. Anyway, did you follow the logic?

[Pegasus1300]

You do remember that when chains break at speed they frequently spin around and take out a case or two or other nearby parts.A Sturdy chain guard, if not already in your plans might be a good idea.

[Rickus Dickus]

Didn't think of that. I just might whip one up and bolt it on. Thanks for bringing it to mind. A little work now can save me a LOT of work later