Gnash Posted July 29, 2008 Share Posted July 29, 2008 Does anyone have experience swapping out sprocket sizes? I want to put bigger sprokets on my 83 XS400. I have stock 16 tooth and 35 tooth sprockets now. I'm rapping 5000 rpm at 55mph. I don't neccessarily wan't to go faster. I just want to run lower rpms at 55mph on the highway. I'm thinking of just getting a 45 tooth rear sprocket from an XS550. Will this sprocket fit on my XS400 wheel, or will I need an xs550 wheel too? My stock chain has 100 links. I'm thinking I will need 104 links, since the xs550 has the 16/45 combo and 104 links. I have found the proper chain and sprocket on ebay for a good price. The listing ends in 1 day. I have also found an 83 xs550 rear wheel with a real good tire, if I need the wheel! I'm putting new tires on my bike next week, so this is the perfect time for the sprocket swap. Thanks. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 29, 2008 Moderator Share Posted July 29, 2008 Does anyone have experience swapping out sprocket sizes? I want to put bigger sprokets on my 83 XS400. I have stock 16 tooth and 35 tooth sprockets now. I'm rapping 5000 rpm at 55mph. I don't neccessarily wan't to go faster. I just want to run lower rpms at 55mph on the highway. I'm thinking of just getting a 45 tooth rear sprocket from an XS550. Will this sprocket fit on my XS400 wheel, or will I need an xs550 wheel too? My stock chain has 100 links. I'm thinking I will need 104 links, since the xs550 has the 16/45 combo and 104 links. I have found the proper chain and sprocket on ebay for a good price. The listing ends in 1 day. I have also found an 83 xs550 rear wheel with a real good tire, if I need the wheel! I'm putting new tires on my bike next week, so this is the perfect time for the sprocket swap. Thanks. 45 tooth sprocket will make the engine turn faster for the the same speed. on my sohc I went 1 tooth bigger on front = 3 less teeth on rear. Link to comment Share on other sites More sharing options...
Gnash Posted July 29, 2008 Author Share Posted July 29, 2008 45 tooth sprocket will make the engine turn faster for the the same speed. on my sohc I went 1 tooth bigger on front = 3 less teeth on rear. Whoa! You mean the 45 tooth sprocket is smaller than a 35 tooth?! I just assumed the more teeth=bigger diameter sprocket. Did you need extra links for that 1 tooth in the front, Drewpy? I'm really confused now. Link to comment Share on other sites More sharing options...
road_rascal Posted July 29, 2008 Share Posted July 29, 2008 Check out this site for gearing explanations: http://www.renthal.com/File/gearing_ratios.asp Link to comment Share on other sites More sharing options...
Cy Welch Posted July 29, 2008 Share Posted July 29, 2008 Whoa! You mean the 45 tooth sprocket is smaller than a 35 tooth?! I just assumed the more teeth=bigger diameter sprocket. Did you need extra links for that 1 tooth in the front, Drewpy? I'm really confused now. Bigger on the back means lower gearing and higher RPM's at speed, bigger on the front means higher gearing and lower RPM's at speed. The inverse is true as well, smaller on the back means more speed, and smaller on the front means less speed. Frankly unless the DOHC has a lot more HP than the SOHC, I think it will bog with much higher gearing. Of course YMMV as I'm a big guy so I need the stock gearing to keep going well. Link to comment Share on other sites More sharing options...
joecool85 Posted July 30, 2008 Share Posted July 30, 2008 I'm looking at regearing my bike as I need new sprockets anyway. What sprockets swap on? I'd like to gear it down for a bit more acceleration. Link to comment Share on other sites More sharing options...
Gnash Posted July 30, 2008 Author Share Posted July 30, 2008 I think it will have plenty of power for me. I'm 180lbs. If not, I can go back. I would like to get the bike to rev 4 grand at 55. It just seems like it would be a pretty easy mod. So I have a 16 tooth sprocket now. Should I try a 17 or 18? Will I need a chain with more links? I have 100 links now. Link to comment Share on other sites More sharing options...
Gnash Posted July 30, 2008 Author Share Posted July 30, 2008 Thanx for the link, Rascal! Reading now. Link to comment Share on other sites More sharing options...
Gnash Posted July 30, 2008 Author Share Posted July 30, 2008 AHA! So, less teeth=higher speed! Got it. I want a 17 or more for front sprocket or less than 35 for back! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 30, 2008 Moderator Share Posted July 30, 2008 AHA! So, less teeth=higher speed! Got it. I want a 17 or more for front sprocket or less than 35 for back! for chain longevity, try for a bigger front sprocket as a smaller rear will mean the chain has to run a steeper angle and wear quicker. i think i use a 102 link, but i buy whatever chain is cheap and cut with an angle grinder to suit using the link! check you have enough room for chain and sprocket first and don't use o ring as that's too fat to fit! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 30, 2008 Moderator Share Posted July 30, 2008 I'm looking at regearing my bike as I need new sprockets anyway. What sprockets swap on? I'd like to gear it down for a bit more acceleration. at first i went 43 rear sprocket (37 stock) and i could keep up with more modern bikes up to 80(even lifts the front end), but it supped fuel and would wear the engine out quicker, your choice. you can use the xs250 sprockets. to recap on european models from my parts book; xs250 front 15T rear 43T england and swiss models xs250 front 15T rear 41T france holland belguim models xs400 front 16T rear 37T 1 tooth on/off front = 3 teeth on/off rear Link to comment Share on other sites More sharing options...
joecool85 Posted July 30, 2008 Share Posted July 30, 2008 at first i went 43 rear sprocket (37 stock) and i could keep up with more modern bikes up to 80(even lifts the front end), but it supped fuel and would wear the engine out quicker, your choice. you can use the xs250 sprockets. to recap on european models from my parts book; xs250 front 15T rear 43T england and swiss models xs250 front 15T rear 41T france holland belguim models xs400 front 16T rear 37T 1 tooth on/off front = 3 teeth on/off rear I would assume that XS360 sprockets would fit as well then? How bad did it gulp fuel with the lower gearing? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 30, 2008 Moderator Share Posted July 30, 2008 I would assume that XS360 sprockets would fit as well then? How bad did it gulp fuel with the lower gearing? cos it was revving higher for the same given speed!!! 360 sprogs should fit Link to comment Share on other sites More sharing options...
joecool85 Posted July 30, 2008 Share Posted July 30, 2008 cos it was revving higher for the same given speed!!! 360 sprogs should fit I know why, I wanted to know how badly. IE - stock you got maybe 65mpg, with the lower gears you got...50mpg? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 31, 2008 Moderator Share Posted July 31, 2008 I know why, I wanted to know how badly. IE - stock you got maybe 65mpg, with the lower gears you got...50mpg? i would say 10 mpg, depends how you ride it Link to comment Share on other sites More sharing options...
joecool85 Posted July 31, 2008 Share Posted July 31, 2008 i would say 10 mpg, depends how you ride it Good to know. Looks like I'm going to buy a set of sprockets, my old ones are thoroughly worn out anyway. I'm going to go 16/39 or 16/40 depending on what I can find. Should give me a bit of extra pep but not kill my highway speeds too bad. The bike won't regularly be going faster than 60mph anyway (speed limit 55mph mostly around here). It might see a trip or two on the interstate at 70-75mph (speed limit 65mph). Link to comment Share on other sites More sharing options...
Moderator drewpy Posted July 31, 2008 Moderator Share Posted July 31, 2008 Good to know. Looks like I'm going to buy a set of sprockets, my old ones are thoroughly worn out anyway. I'm going to go 16/39 or 16/40 depending on what I can find. Should give me a bit of extra pep but not kill my highway speeds too bad. The bike won't regularly be going faster than 60mph anyway (speed limit 55mph mostly around here). It might see a trip or two on the interstate at 70-75mph (speed limit 65mph). i'd go at least 3 sizes = circa 500rpm Link to comment Share on other sites More sharing options...
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