Sprocket Change

[Sky King]

I got another shake down ride in today, 40 some miles of mountains and twisties. The bike ran good and I think the carbs are sorted, the clutch still leaves a few things to be desired so I'll be working more on that, but what stood out on this ride was the stock gearing, it was too high for my liking. To get to the highway from my house I have to use a rough steep dirt road, first gear is higher than I like for that terrain and also for the town portion I did when I went to get gas. The previous owner replaced the chain and it's a bit on the short side so I would like to change the front sprocket as an extra tooth or two in the back won't work with the short chain. So from the stock 17 tooth front sprocket I would like to drop it one tooth or two. I know I will loose some top end but the question is how much and which would be best a 16 or 15 tooth sprocket. What sort of 1st gear speed and top gear cruising speed can I expect with those changes?

 

[5twins]

I've never seen a 15 or 16T front sprocket offered for these. It would be harder on the chain because it would turn around a tighter circle. I have seen 36 and 38T rears though, and that may be your only option. I think a 36T came stock on some of the Canadian Specials. A 16" rear wheel would effectively gear it down a little as well. Here's a gearing chart that may help you decide ......

Most of us gear these up a little bit. You're the first guy I've seen who wants to gear it down, lol.

 

[5twins]

And the stock 17-34 gearing gives a nice 2-1 ratio, so going one tooth on the front pretty much equals 2 teeth on the rear.

 

[Signal]

A 16 will fit but dont think a 15 will fit with a 530 chain too tight a turn.
16 T fronts from Yambits UK. https://yambits.co.uk/front_sprockets_parts_for_yamaha_xs650.html

 

[arcticXS]

And the stock 17-34 gearing gives a nice 2-1 ratio, so going one tooth on the front pretty much equals 2 teeth on the rear.

Hmm, I thought ratios like that were normally avoided where possible (i.e pretty much everywhere except cam drives), to avoid same gear teeth/ chain links meshing all the time, potentially creating unique wear patterns, which then could cause issues if somehow assembled differently at some point.

 

[5twins]

Well, that may be true, but that's the gearing that the U.S. models came with for their entire production run, and it didn't seem to cause any issues that I've ever heard of.

 

[Wagner73]

When I first got mine from the PO and rode it, it seemed like it didn't have the first gear punch I would've expected, and lo and behold when I pulled the left cover, there was an 18T sprocket. It was a tight fit to the clutch rod. Replaced it with 17T.

Point being, if you haven't examined the front sprocket, you might find something?

And per 5twins, I as well have never seen <17 for this application

 

[arcticXS]

And per 5twins, I as well have never seen <17 for this application

That makes perfect sense, as going to a more "normal" size rear sprocket (35 to say 42 teeth) would be the better way to lower gearing. If that is desirable for a particular use.

 

[Its been a long time]

Well, that may be true, but that's the gearing that the U.S. models came with for their entire production run, and it didn't seem to cause any issues that I've ever heard of.

It's not going to cause issues because on a motorcycle the chain and sprockets are simply consumable items.

 

[tibsy]

I seem to recall reading yrs ago that US models of most Makes/models ( not just Yamaha ) had lower gearing(sprocket wise) than European bikes.
Something to do with US preference for acceleration and "about town riding", rather than European preference for Motorway/MPG riding.
I might of course be talking complete b******s, it`s just something i seem to recall!

 

[jetmechmarty]

I seem to recall reading yrs ago that US models of most Makes/models ( not just Yamaha ) had lower gearing(sprocket wise) than European bikes.
Something to do with US preference for acceleration and "about town riding", rather than European preference for Motorway/MPG riding.
I might of course be talking complete b******s, it`s just something i seem to recall!

No. You’re correct. XS650 in the U.S. market got a 34 tooth rear sprocket. In the EU it’s 33 teeth. All front sprockets were 17 teeth AFAIK.