My experience changing final gearing for better mileage (14-43 -> 16-41)
I bought my R3 not because I wanted a racing/sport bike specifically but rather because I wanted a motorcycle and I heard the R3 was a good bike to learn on. It's also popular enough that I hoped spare/aftermarket parts would be cheap and abundant, and I found a pretty good deal for a new-old 2016. No ABS unfortunately, though I know opinions on ABS are mixed.
So you can have some perspective on who's writing this, I don't have super high performance expectations. For example, even if I didn't know about the break-in period I doubt I'd ever have gotten the engine above 7000 RPM. I pretty much just take it easy.
Why I wanted to do this:
My immediate concern was that first gear felt useless; I felt like I needed to shift into second before I was even through an intersection. This instinct led to some hair-raising experiences where I shifted with the bike leaned a bit while turning left from a stop. Not a good idea apparently.
Another thing I hoped to improve was my gas mileage. Unfortunately I don't have a record of my gas mileage before the sprocket change. My hope was to reach ~80 MPG at 80 KM/H (50 MPH), which would also help to extend my range without a backup gas can. My gearing changes should hopefully (?) also be easier on the engine and drivetrain, extending lifespan somewhat.
Using Gearing Commander I found that if I remove a tooth in the rear for every tooth I add in the front, I don't need to unnecessarily replace my factory-new chain. A 16 tooth front sprocket was the biggest I could find so I went with a 41 tooth rear sprocket. The rear axle is still in roughly the same place as it was originally, maybe off by 1mm or so.
B]The parts I purchased:[/B]
- JT Sprockets 520 Front Sprocket 16 teeth
- JT Sprockets 520 Rear Sprocket 41 teeth
- Speedo Healer V4.0 Control Unit
- Speedo Healer V4.0 Harness (SH-H05)
As it turns out, the 17 tooth front sprocket I'd originally hoped to buy would've been a mistake anyway. A 16 tooth front sprocket is a hair too big and it causes the chain to rub against the plastic cover for the front sprocket. I've put ~800 KM (500 miles) on it since changing the sprocket and I don't hear a rubbing noise anymore; I expect it's "worn in" by now. When I said it's a hair too big, it really is just a hair. It barely touches it, at least with the sprocket I got.
I'm really sorry I'm hazy on this, but I remember using a dremel at one point. This was over a month ago and I've done a lot of other work on the bike and around the house since then, so I don't remember what specifically I did with it. Sorry. It probably would've been cutting out a spot where the chain would rub, likely at the top or bottom of the cover where the chain enters/exits. I know it was a tiny adjustment, a millimeter or two... so have a dremel on hand, you'll figure out quickly what needs to be done.
The rear sprocket was fine, no issues at all besides rookie mistakes and it being a PITA to get the rear brake caliper to cooperate while putting the wheel back on. Watch for those spacers. Have something on hand that you can put beneath the rear wheel to help you hold it in place while you put the axle back through, some books or something.
I replaced the sprockets with very minimal mechanical knowledge only aided by YouTube videos (STG has everything you need), so I highly recommend this as a beginner-intermediate mod. It took me a few hours since I was unsure of myself; I could do the same job again in less than an hour. For the rear axle IIRC you'll need a 19mm and 22mm socket, while the front sprocket's giant nut will require a 29mm socket and an extra-long handled rachet for better leverage because it's on there tight from the factory. You'll need rear spools and a spool jack thing, not expensive. Use a torque wrench to re-tighten all bolts/nuts to factory spec. IIRC you need locktite on the front sprocket's bolt. Be careful with routing the cables that go near the front sprocket, they need to go back where they started when you put the cover back on.
Speedo Healer is a device that adjusts the tachometer & odometer to account for the different gearing. Without it (or something similar) your speedometer and odometer will give inaccurate readings. It's a little tricky to install without instructions but I think STG has an install guide video on YouTube. I found I needed a 10% offset from the factory calibration to get it GPS-perfect but you should check this for yourself. Speedo Healer is difficult to find in Canada. Bayside Performance sells them, though I found them to have pretty miserable customer service and false stock listings on their website (which still hadn't been corrected when I checked back months later).
I used to be able to get into 6th gear while just cruising around town at ~55 KM/H (34 MPH) without lugging the engine, while it's now more comfortable at around 70 KM/H (43 MPH). That, in my mind, is the sort of speed a 6th gear should be for.
First gear now feels much more useful and there's no longer something in the back of my mind telling me I should be shifting into second even before I'm out of an intersection, which is a huge safety thing (for me as a beginner at least). If I need to accelerate quickly I can hit ~30 KM/H (19 MPH) at around 5000 RPM in 1st gear, which isn't obnoxiously loud.
I really don't want to be one of those people that wakes up the neighborhood, so the generally lower RPM (about a 16.6% reduction) is nice for that.
I can't say for sure - it might only be due to gaining experience - but I find the bike is now more forgiving when starting from a stop. It's more tame and feels easier to leave a stop sign with a measured pace rather than either stalling or accelerating overly fast. Again, this could easily be down to gaining experience. I CAN still accelerate fast if I want to, but it's not something I do by accident. I like how it feels better, in any case.
If I'm going 80 KM/H (50 MPH) in sixth gear (for reference now ~4200 RPM on flat), I can slowly accelerate while going up a quite steep hill. As I understand it, 4200 RPM is well below the bike's power band, so if I was moving at highway speed (~110 KM/H / 68 MPH, 5800 RPM), I'd probably still be good even considering greater air resistance.
With my previous gearing, if I needed to quickly pass someone on a highway I'd ideally be in 5th to have the best acceleration past 120 KM/H (75 MPH), while now 4th is where I'd want to be.
I spend probably 60% of my time on county roads doing 85 KPH (53 MPH) or so. At best I'm now getting 3.8-3.9 L/100 KM (72-75 MPG imperial, 60-62 MPG US). Yamaha estimates 63 MPG imperial (56 MPG US). That was before the first service, which I've heard may improve mileage. I just did my first oil & filter change yesterday and haven't had it out again since then.
I can't speak for how sporty it feels now since I don't really have a point of comparison. It's my first bike and I only rode it a couple hundred KM with the original sprockets. Without riding like a complete dick I can still easily leave an intersection before anyone else has reached the half-way point, sometimes before they've even passed the crosswalk. I'm not a racer, so if the only thing on the road faster than me is another motorcycle, that's more than good enough in my book. I doubt I'll be doing any wheelies with this gearing, I've never tried it and don't intend to.
When it's time to get a new chain/sprocket set I'm planning to go even further and try a 110 link chain (stock is 112 and would be too long I think) with 16/38 sprockets (a further 7.3% RPM reduction) to see how that feels. With 16/38, I'd be running around 3300 RPM in 4th gear around the city at 50 KM/H (31 MPH), 3900 RPM in 6th on county roads at 80 KM/H (50 MPH), and 5400 RPM in 6th on the highway at 110 KM/H (68 MPH).
Any truth to what I've heard about MPG improving after the break-in period? Due to a surgical procedure (thankfully unrelated to motorcycling) I can't ride for another week or so, so I'm curious what I might find.