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Increasing speed

20K views 24 replies 14 participants last post by  kiwi rider 
#1 ·
What kind of mods can you add to a CB300F to increase speed? I heard you can change the sprocket, If so, adding teeth or subtracting teeth? What other mods?
 
#2 ·
Changing the sprocket will affect whether the bike is geared higher or lower. It won't increase speed. Some people add a sprocket with more teeth because the complaint is that the bike is screaming at you in 1st gear. As I said though, no increase in speed.

I don't know, maybe if you put on a smaller sprocket you might be able to push a little more speed out of the bike on the freeway in 6th gear.

There have been many threads on the subject indicating that you can increase performance either by dropping weight from the bike, or doing a combo exhaust/filter mod. The general consensus was that you might get add 1 or 2 hp, but the difference is marginal.
 
#4 ·
You won't find any horsepower in a set of sprockets! You will find one or two in a slip on but probably at the expense of a little low RPM torque. You would most likely find another one or two by adding a fuel re-map but they are expensive ponies!
Shedding weight helps but again, its small gains.

You've pretty much got what you've got :D
 
#24 ·
You won't find any horsepower in a set of sprockets! You will find one or two in a slip on but probably at the expense of a little low RPM torque. You would most likely find another one or two by adding a fuel re-map but they are expensive ponies! Shedding weight helps but again, its small gains. You've pretty much got what you've got :D
If you look at the data for good quality slipons you'll find the biggest gains are between 3000 and 5000 rpm not power loss at lower rpm.
 
#8 · (Edited)
I haven't ridden my CBR3R flat out yet (still running it in) and so don't know, but lengthening the gearing will only provide more top speed if you can redline the bike in 6th. Power and aerodynamics together might actually be the limiting factor, not gearing. If it won't rev out in top with standard gearing, gearing longer won't help - and might actually make things worse.

It wouldn't hurt to try. Just don't change it too much. Even if top speed doesn't go up, you might appreciate the lift in first gear ratio (very low as standard) and you might also see an improvement in everyday fuel consumption.

Also be aware that longer gearing will be detrimental to acceleration, particularly when carrying a pillion and/or going uphill. As my father used to say, "You get nothing for nowt."
 
#9 ·
You can do a complete aftermarket exhaust, an aftermarket air filter, and using something like a Bazzaz self-mapper and ZFi unit to tweak the fuel mix to run richer.

But given the cost of all that, I'd say such mods are only worth it on 600cc and above supersports.

I've been down this road before on a (lol) 153cc scooter, which was the Honda PCX 150.

The mods were more extensive including a big bore cylinder, performance camshaft, stiffer valve springs, and an aftermarket EFI which also raised the rev limiter. All in all I think I saw maybe 8-10mph gain after shelling out 5 grand to trick it out. Looking back on it, if I had just kept that money instead and sold it stock, I could have easily afforded something like the CTX700N.
 
#14 ·
Yet there are a lot of people who buy small bikes and put a lot of money into trying to eek out another 10 mph for them...air box alteration, exhaust, big bore kits. The Grom comes to mind. Like they say, "there's no replacement for displacement". Everyone who likes speed should experience an in-line 4 600cc bike. There is nothing you can do to the 300cc engines to rival that, plus then the suspension and brakes on 300s are not designed for higher performance.
 
#22 ·
Whenever I read, "This bike isn't fast enough" or "The CBX$RD doesn't brake as good as my mate's Ducati" I just just see, "I bought the wrong bike"

I often think this way when I see guys on cruisers (i.e. Harleys) thundering around twisty roads, or drivers of large 4WD SUVs dragging away from traffic lights. Guys, you bought the wrong thing!

When it comes to being cheap, weighing very little, being easy to handle, having good looks, having Honda build quality and being 300cc........

Well, nothing beats the CBR300R or F!
 
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#23 ·
I meant to add (but the edit function wouldn't let me), that despite smiling when I see bikes/cars used for purposes they aren't designed for, I accept that most people will only buy one bike and so they have no choice but to try! Hopefully, they will have the sense to realise this though, and not complain that their 300cc single is slower than a 600cc four costing three times as much.

;)
 
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