[MeeLee]

What's the top speed of your Rebel then MeeLee?? :laugh:

Now it's tuned for fuel efficiency, and probably doesn't go above 87MPH on a good day (feet on passenger pegs, and ducked forward).
I hardly take it out at anything above 82MPH anymore.


But yeah, get the rebel revving at 6600RPM top speed, and you'll surpass 87MPH easily; or, sit upright, feet on pegs, and go only 82MPH...

 

[kiwi rider]

But yeah, get the rebel revving at 6600RPM top speed, and you'll surpass 87MPH easily; or, sit upright, feet on pegs, and go only 82MPH...

87MPH @ 6600RPM huh... You must have it geared for hypermiling! :laugh:

 

[thisberich]

I've had mine up close to 100mph without mods & lying flat on the tank (behind the windshield), tucked in, wearing slim-line clothing.

Wouldn't like to have it up there for long as it was straining. I've got my eye on a Scorpion slip on. If I get that it might go over the 'ton up'.

 

[CDNHONDAR]

That pretty well sounds normal (from what I have read) for stock machines. Are you planning on increasing the front sprocket by one tooth (15 teeth) as many have done here???

 

[Mark65]

That pretty well sounds normal (from what I have read) for stock machines. Are you planning on increasing the front sprocket by one tooth (15 teeth) as many have done here???

I would like to try the 15 tooth, but don't want to hack away at the sprocket cover. That is if I could find a 15 tooth here, usually use JT sprockets.

Mark

 

[kiwi rider]

I would like to try the 15 tooth, but don't want to hack away at the sprocket cover. That is if I could find a 15 tooth here, usually use JT sprockets.

Mark

You don't have to modify your sprocket cover at all. I'm guessing you got that info from an earlier post of mine perhaps which was incorrect.
I just needed to hold my tongue in the right place

You should be able to find them easily in the UK I would have thought.

 

[Mark65]

No luck yet in finding one, you can get a 13 tooth, not even a cheap make in 15 tooth.

 

[kiwi rider]

No luck yet in finding one, you can get a 13 tooth, not even a cheap make in 15 tooth.

Surprising.

Any UK members out there done the 15T front sprocket conversion?

This is one of those searches best done using CBR250R as the keyword.

Its also the same front sprocket as the XR250 trail bike 1996 - 2004. I know this because my packaging had that stamped on it.

 

[CDNHONDAR]

I know I have checked on E bay (USA/UK) and no luck.

 

[MeeLee]

It appears to me, if my calculations are done correct,
basing myself on this graph:

That the CB300F has peak HP at around 8500RPM,
This is the sweet spot for reaching top speed.
Current top speeds I've seen are done at between 10 and 10.5k rpm, where the engine makes just short of 2HP less power then at 8500RPM.
It's not a lot, of increase, but every bit can help.

From what I've seen from youtube videos so far, is that the CBR300R seems to be able to top 100MPH, while the CB300F's best youtube video top speed seems to be only 87MPH.
The CBR rider did lean forward, the CBF rider sat upright.

Presuming both bikes can do 95MPH when leaning forward, to gain most top speed you'd have to change the sprockets from a 14/36t, to a 15/34t.
Suppose that the CB300F could only reach up to 90MPH, with the mod, it should be able to reach 95.
If it did 95MPH stock, it might even come close to 100MPH.

Coincidentally the largest front, and smallest rear sprocket, is also the setup for highest top speed.

If the bike could do 100MPH stock, like the CBR300R, you would have been best off with a 15/32 setup, or a 16/34t should such a thing fit in the bike (for reasons of maintaining top speed, not acceleration).

Me personally, I prefer to have one gear above the gear that the bike can maintain it's top speed.

If the CB300F needs to rev around 3k RPM minimum to maintain speed, and most of my traveling is at >35MPH,
For me the best sprocket setup would be a 15/29t, which allows me to maintain 40MPH speed in 6th (at 3k RPM), and top speed in 5th; if they only had a rear wheel that would fit the sprocket.

My Riding style is relax, and based on economy riding; not fast acceleration... just saying...

 

[ASMIKE]

This last weekend I had a chance to open up our little 300r a bit. I had a friend with me on his Ducati but he wasn't paying attention to his speedo. My speedometer was reading 92 mph before the traffic become too heavy and I had to back off. This reading is inaccurate as the front sprocket is up 1T from stock. I'd be guessing right about 100mph.

I just removed the rear fender this weekend, you can see the finished product in my build thread, so I'll try another speed run to see how much aerodynamics play a role in this bikes top speed.

 

[CDNHONDAR]

Thanks Mike...let us know your results..

 

[MeeLee]

Yeah, and please clock your speedo with a GPS as well.
Just download a GPS app in your phone, and throw it in a pocket while having it record your speed.

 

[ASMIKE]

Yeah, and please clock your speedo with a GPS as well.
Just download a GPS app in your phone, and throw it in a pocket while having it record your speed.

That sounds like a plan. I'll have to find one that will give me recorded peak speeds.

 

[MeeLee]

Most GPS apps do.

 

[BoBo Toy Copter]

I don't have a CBR300 yet, but my Ninja 250 gets up to 106 mph all stock, and about 112 when it had a full exhaust and tuning done.

 

[AJ Nin]

I think the actual top speed of the Ninja 250r is just under 100 mph. Like most motorcycles, the speedo is off a little and some people measure the top speed going down hill or with a tail wind. The Ninja 300 actual top speed is about 105 mph as I recall. I haven't checked my CB300F speedo, but judging from surrounding highway traffic, the speedo is pretty accurate at 75 mph. Anyway, all these bikes work on the highway. The question comes up about how hard the engine is working at highway speeds too. I recall my Ninja 250r sounded like it was working pretty hard at 80 mph, like that wasn't a speed that was good for the engine although it was under redline. When that occurs, you have to constantly remind yourself to keep the throttle open more because the natural tendency is to back off from straining the engine and suspension. Whether it actually hurts anything to ride at high speeds on the Ninja 250r is another question. Most Ninja 250r owners would argue no. The Ninja 300 is just a much better bike for high-speed riding in terms of the bike being much better planted and not working nearly so hard. I think the Ninja 300 is still at the top of the 300s for high- speed riding. The R3 which I also owned is good too but I still like the Ninja 300 best. Let's just say having owned all these bikes, but not the CBR300R yet, the Ninja 300 is the one to beat. There are a couple of videos showing the Ninja 300 edging out the R3 for top speed too. That might be due to the fact the engine of the Ninja redlines slightly higher than the R3. The single cylinder, lower redline, smaller displacement CBR300R is not going to be as fast as the Ninja 300 or the R3 by 8-10 mph.

 

[CDNHONDAR]

Great write up thanks very much. So you no longer have the Yamaha R 3? If not why?

 

[AJ Nin]

I traded it in late June for a new GSX-r600. I didn't like 2 things about the R3. First there was a gear sound that was annoying in 3rd and 4th gear. Other people had it too, but some said it went away. Mine didn't. The other thing I didn't like, and all the R3s I've seen are like this, they lean too much toward the kickstand...just the opposite of my CB300F. Not enough for the bike to fall, but enough that It was a bit of a strain to push the bike upright just to back it out of my garage. Of course I could have fixed that problem, but I just don't keep bikes very long generally. I've had 3 Ninja 300s...2 2013s and a 2014. What I came away with is that for me, the CB300F is the best city bike which is most of my riding and the Ninja 300 is the best highway bike, but I haven't ridden the CBR300R to compare that bike. The R3 was very stable at higher speeds and otherwise very similar to the Ninja 300. Probably if it didn't have that gnawing gear sound, I would still have it. I love the GSX-r600 though. Already have 5700 miles on it in 4 months.

 

[CDNHONDAR]

Other than the fairing the CB300 and the CBR 300 would be very similar performance wise. I have ridden the "R" version a couple of times but not the "F" version but I am pretty sure the "R" version would be better as far as wind protection.