Topic: $#@%ing p.o. - sprocket help?

[domer]

72 CB500, had a bad oil leak so i tore into her, no biggie. in the process i noticed that the chain was rubbing the case. woo-hoo, p.o. used an o-ring chain, lucky for me i caught it before it got bad. no leaks and only about 1/32" deep. so I'm looking for a new chain, and i was asked what size sprockets i have. good question. so i run home to check, to my suprise its running a 18t front and 37t rear. now I'm not a math whiz, nor do i know #$%* about gearing. i am obviously going to have to change this, but why would someone use a gear ratio like this?
on another note, Ive read that an 18t will not fit on the front. Ive put about 1200 miles on that chain sprocket set up and shy of a little wear on the case from the chain, i cannot find any spot where it has touched? i don't have a license (lazy) so i don't take it on the freeway often at all, but i did notice it kind of whines out at 65... but what do i know! thoughts?

[scunny]

sorry, can't remember the stock ratio for the 500 but heres a ratio chart to help your maths
http://www.jtsprockets.com/fileadmin/files/jtgearratio.pdf

[dave500]

17x34 is the stock 500,the 550 had 17x37 i think,i tried a 37 on my 500 and its way low for me on the road,the 550 had a different primary reduction i think.

[eideteker]

http://www.gearingcommander.com/

According to that site, there isn't a big difference between 17/34 and 18/37 - only 3MPH on the top end and little difference elsewhere.  Maybe the PO got a really good deal on that sprocket combo or couldn't find stock size replacements?  If you're going to do a lot of freeway riding at any point, you should go back to stock sprockets or even a couple teeth smaller than stock on the rear to bring the revs down at cruising speed.  Check out Sprocket Specialists - got mine from them.