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Thanks Motorboy. I look at the oil in the sight glass, and when it starts getting dark, it's time to change it and I expect that long before 8000 miles. It's getting brown already! And to confirm, if I change only the front sprocket to a 15T the max torque will be reached around 7500 rpm which will let me cruise at 65mph without stressing the engine?
I do my oil changes at about 6000 km's (3800 miles) with Rotella T6 5W40 (It's JASO MA certified and synthetic whereas the stock GN4 oil is 10W30 and I believe is dino/conventional oil).

Sprocket change doesn't do anything to the torque or HP, nor where your bike reaches it's max torque/HP. What it does is change how many revolutions you need to do in order to drive the wheel the same distance. If you understand bicycle gearing then it's immediately translatable.

But basically, just because you change the size of your sprocket doesn't mean that your legs can output any more or less power. What it does do is let your legs spin the cranks at a lower RPM when going the same speed.

Basically, with the 15t sprocket highways will be less "buzzy" because you're in a lower RPM for the same given speed. I personally think that it also makes the gearing better and more usable especially starting off at a stop light and when at high speeds on the highway (I do a buck twenty at 7000 RPM with the 15t whereas before would need to be sitting at 7700RPM to do the same speed).

I did the calculations once before and IIRC the numbers I got were 100 kph at 6500rpm (~60 mph) on stock gearing, and with the 15t sprocket you're able to do 110 kph (~67 mph) at the same 6500 rpm. You do gain top speed, but you don't actually "lose torque" because torque doesn't necessarily equal acceleration. On two sides of the extremes; Imagine an ocean freight ship that has tons of torque available but doesn't actually get up to speed, then on the other side imagine the nimblest of sportbikes that doesn't have as much torque available but can accelerate fast.

Also note that you can't take this to the extremes because you still need to consider power available to you from the engine. ie. don't try putting a "Dinner plate" sized front sprocket (ignoring space limitations like an 18 tooth (+4)) and a "shot glass" sized rear sprocket (eg. 32 tooth rear (-4)) and think that with this combo you can achieve 200 kph if you had a long straightaway because the engine will not be able to produce enough power to overcome the parasitic drag (which is exponential) of moving through air (which is technically considered a fluid.
 

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Thanks Motorboy. I look at the oil in the sight glass, and when it starts getting dark, it's time to change it and I expect that long before 8000 miles. It's getting brown already! And to confirm, if I change only the front sprocket to a 15T the max torque will be reached around 7500 rpm which will let me cruise at 65mph without stressing the engine?
Max torque on this bike is at 6,500 rpm stock gearing 60mph -15 T counter 65mph-but unless you put a speed healer to correct the speedo it will look the same-60 mph showing will be 65mph
 

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Discussion Starter · #23 ·
Thanks Motorboy. I look at the oil in the sight glass, and when it starts getting dark, it's time to change it and I expect that long before 8000 miles. It's getting brown already! And to confirm, if I change only the front sprocket to a 15T the max torque will be reached around 7500 rpm which will let me cruise at 65mph without stressing the engine
I do my oil changes at about 6000 km's (3800 miles) with Rotella T6 5W40 (It's JASO MA certified and synthetic whereas the stock GN4 oil is 10W30 and I believe is dino/conventional oil).

Sprocket change doesn't do anything to the torque or HP, nor where your bike reaches it's max torque/HP. What it does is change how many revolutions you need to do in order to drive the wheel the same distance. If you understand bicycle gearing then it's immediately translatable.

But basically, just because you change the size of your sprocket doesn't mean that your legs can output any more or less power. What it does do is let your legs spin the cranks at a lower RPM when going the same speed.

Basically, with the 15t sprocket highways will be less "buzzy" because you're in a lower RPM for the same given speed. I personally think that it also makes the gearing better and more usable especially starting off at a stop light and when at high speeds on the highway (I do a buck twenty at 7000 RPM with the 15t whereas before would need to be sitting at 7700RPM to do the same speed).

I did the calculations once before and IIRC the numbers I got were 100 kph at 6500rpm (~60 mph) on stock gearing, and with the 15t sprocket you're able to do 110 kph (~67 mph) at the same 6500 rpm. You do gain top speed, but you don't actually "lose torque" because torque doesn't necessarily equal acceleration. On two sides of the extremes; Imagine an ocean freight ship that has tons of torque available but doesn't actually get up to speed, then on the other side imagine the nimblest of sportbikes that doesn't have as much torque available but can accelerate fast.

Also note that you can't take this to the extremes because you still need to consider power available to you from the engine. ie. don't try putting a "Dinner plate" sized front sprocket (ignoring space limitations like an 18 tooth (+4)) and a "shot glass" sized rear sprocket (eg. 32 tooth rear (-4)) and think that with this combo you can achieve 200 kph if you had a long straightaway because the engine will not be able to produce enough power to overcome the parasitic drag (which is exponential) of moving through air (which is technically considered a fluid.
Great info, thank you. If I take the plunge and put a 15T up front, can I leave the back as is or do I need to change it too, and is so, to what?
I do my oil changes at about 6000 km's (3800 miles) with Rotella T6 5W40 (It's JASO MA certified and synthetic whereas the stock GN4 oil is 10W30 and I believe is dino/conventional oil).

Sprocket change doesn't do anything to the torque or HP, nor where your bike reaches it's max torque/HP. What it does is change how many revolutions you need to do in order to drive the wheel the same distance. If you understand bicycle gearing then it's immediately translatable.

But basically, just because you change the size of your sprocket doesn't mean that your legs can output any more or less power. What it does do is let your legs spin the cranks at a lower RPM when going the same speed.

Basically, with the 15t sprocket highways will be less "buzzy" because you're in a lower RPM for the same given speed. I personally think that it also makes the gearing better and more usable especially starting off at a stop light and when at high speeds on the highway (I do a buck twenty at 7000 RPM with the 15t whereas before would need to be sitting at 7700RPM to do the same speed).

I did the calculations once before and IIRC the numbers I got were 100 kph at 6500rpm (~60 mph) on stock gearing, and with the 15t sprocket you're able to do 110 kph (~67 mph) at the same 6500 rpm. You do gain top speed, but you don't actually "lose torque" because torque doesn't necessarily equal acceleration. On two sides of the extremes; Imagine an ocean freight ship that has tons of torque available but doesn't actually get up to speed, then on the other side imagine the nimblest of sportbikes that doesn't have as much torque available but can accelerate fast.

Also note that you can't take this to the extremes because you still need to consider power available to you from the engine. ie. don't try putting a "Dinner plate" sized front sprocket (ignoring space limitations like an 18 tooth (+4)) and a "shot glass" sized rear sprocket (eg. 32 tooth rear (-4)) and think that with this combo you can achieve 200 kph if you had a long straightaway because the engine will not be able to produce enough power to overcome the parasitic drag (which is exponential) of moving through air (which is technically considered a fluid.
Great info, thanks again. So, if I take the plunge and put a 15T up front, can I leave the back as is or do I need to change it to, and if so, to what tooth?
 

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Great info, thanks again. So, if I take the plunge and put a 15T up front, can I leave the back as is or do I need to change it to, and if so, to what tooth?
All you need is the 15 tooth front sprocket. The rear can stay the same (36t) and the chain can stay the same as well. Don't ever think about 520 vs 525 or 530 chains. The 520 pitch is good enough and even if you tuned it to the tits it'll never make enough power to make it matter where you need to worry about going with a 525 pitch.

Basically this countershaft sprocket up in the front https://sunstar-braking.com/countershaft-520-15t.html?type=MMY&s=on-road-honda-cbr300r-2015-3920551

Then follow this video guide:

All you need is simple hand tools but if you're not confident enough then take it to an independent mechanic and they'll probably charge you like half an hour of shop time for a junior mechanic to do it for you even if the job itself is simple enough to do.
 

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Discussion Starter · #25 ·
All you need is the 15 tooth front sprocket. The rear can stay the same (36t) and the chain can stay the same as well. Don't ever think about 520 vs 525 or 530 chains. The 520 pitch is good enough and even if you tuned it to the tits it'll never make enough power to make it matter where you need to worry about going with a 525 pitch.

Basically this countershaft sprocket up in the front https://sunstar-braking.com/countershaft-520-15t.html?type=MMY&s=on-road-honda-cbr300r-2015-3920551

Then follow this video guide:

All you need is simple hand tools but if you're not confident enough then take it to an independent mechanic and they'll probably charge you like half an hour of shop time for a junior mechanic to do it for you even if the job itself is simple enough to do.
Went to purchase the 15 via your link, but it does not list the 2019 CB300R as a purchase option.
 

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