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Discussion Starter #1
Hi All,
I am interested in adjusting the final drive in my 73' CB350 to help lower RPMs when cruising at 45/50. I've seen a few sites offering reduced drive sprockets, or increased output sprockets. I'm wondering which is the better option for reducing RPMs at cruising speed? Also, I have done a lot of work with bicycles and I know that you are replacing any of the three components due to wear, that you should be replacing the other two (input sprocket, output cog and chain). Is this also the case here? I know chain slipping is a mild irritant on a bike, but could be disastrous on the motorized variety. Also, the bike has about 20k miles on it, stored inside and in very good shape, but it does have wear on the moving elements appropriate to it's mileage.

Any inputs or advice are greatly appreciated. Also, if this is just a bad idea from the start, let me know why.

Thanks in advance!
 

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Consider what your average cruising speed will be in the geography where you ride.
I changed the ratio on mine by (1) tooth to a (17) tooth in the front. This lowers the Avg. RPM
My town has a 25 MPH speed limit and in town I rarely get out of 2nd gear, but that's when I'm just running short errands.
I mostly take the bike out for rides out of town where the Avg. Speed Limit is over 45 - 60 MPH and it gives me a nice comfortable ride.

Just understand that you need to keep the RPM's up over 3500 Min for the charging system to operate correctly, and you'll be better off over 4500 RPM Avg. as these bikes just begin to make their power at about 6000.
 

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Yes, I went up one tooth on the front sprocket too. Seems to be a good compromise if you ride on the highway very much. I don't replace the sprockets every time I replace the chain. It's pretty easy to examine the sprockets visually, and if the teeth aren't getting pointed (or worse. hooked), I just replace the chain. That said, on bikes with chains that last a lot longer (like o-ring chains), the sprockets probably do wear out about the same time as the chain. Don't try to use an o-ring chain on a 350, though - there's not enough room for the extra chain width.
 

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Discussion Starter #4
Hey Yendor,
Thanks for points to consider there. I hadn't thought about the minimum RPMs, but I don't think I'll have an issue there as most of my riding is done on 45-60 MPH roads, but I will have to watch for that if I go forward with this.

XLX,
Thanks for the Sprocket/chain considerations.

Also, as far as sourcing do any of you have a preferred place? I found them on Common Motors, but I'm wondering if there's anywhere else I should be considering.

Thanks Again!
 
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