Honda CBR 300R upgrade from 250..

[ja99]

Having owned a CBR250R for 16months, riding around 9000kms and then selling it, I thought I was done with road bikes and would stick with riding bigger scooters such as the PCX. That is, until I walked into the same dealer and eyed a pristine CBR300R Repsol edition with 950kms on the dial. How could I resist, given a reasonable asking price, I did the the unthinkable and plonked it on my credit card!

So then, after a month's ownership and 1500kms added, how does it compare? As has been noted in other topics, the engine is only 286cc but it packs that extra bit of punch (30.5HP?) and low down torque to make it more likeable than it's predecessor. The bike pulls from 2000rpm without much complaint, from memory the 250 balked at under 3000. But it isn't perfect and there are a few minor gripes which I feel the need to air..

Firstly, one wonders why Honda persists with the IRC Road Winner tires or 'Road Killers' as per other forums. Take a look at the Yamaha equivalent R3 fitted with Michelin Street Pilots, a much better choice although that bike sells for an extra 45K baht.

Other gripes in no particular order:

There is no real security system apart from the steering lock. A chipped key would be nice whereas the current key can be duplicated at any key cutting center! No need to go to the Honda shop at all, the tag number is just for show by the looks. Touch wood, thieves must love these bikes. As an aside, Tesco sell a hefty looking lock with inbuilt alarm for 499baht, next on my purchase list..

Apart from the green Neutral light, there is no gear position indicated on the dash which I find annoying at times. After all, my friend's ancient Yamaha 100 Fresh model 4 speed has a light for each gear, lol. So, how hard can it be Honda?

The new, bigger horn button on the 300 is literally hit and miss and I am still not used to it. The older version was easier to reach IMO.

The headlights are very stylish, however low beam seems to be pointed too high and to the left, maybe needs adjustment.

The exhaust is certainly a visual improvement over the 250, makes for a quiet ride but I have managed to place my calf against the protective plate when standing and perhaps stating the obvious, it is still pretty hot. Time for a Leo Vince carbon slipon perhaps. Also, the stock exhaust looks very heavy, be interested to know the weight if anyone has bothered? After all, power to wieght ratio is a factor in performance.

If you like being anonymous, dont get the Repsol paintjob, it gets a fair amount of attention.

So, all in all, it is a great bike, excellent value given it is way cheaper than the competition, looks like a keeper..

[Dutchbike]

It looks like this forum is a bit "CBR tired" or something :-) Since no one replied, thanks for taking the time to write your report, if I was to purchase a CBR 300 it certainly would be a Repsol edition, they look sweet, I wish you many safe km's on your bike.

[wow64]

They are a good bike for commuting... Nimble and cheap on fuel... Better for a 6ft person then the ninja..

Sent from my c64

[Rhys]

I think you will get bored eventually.. Move up to the 500 or 650... At the time, the 300/286 was fine, but afterwards became bored..Odd, I bought it the first of the year and I have less than 2k on the bike... I will move up.. keep it for about town.

Cheers mate

On the pegs

Edited November 10, 2015 by Rhys

[Richard-BKK]

You should not try to upgrade the CBR250R with the original CBR300R parts. You should try to get the Takegawa 305cc big bore kit, which gives you just over 10 horsepower extra push.

[papa al]

He upgraded 250 ==> 300 using 100% original 300 parts.

He bought a different bike.

Smarter than a Tagawatever big bore IMO.

Edited November 11, 2015 by papa al

[Martin54]

You should not try to upgrade the CBR250R with the original CBR300R parts. You should try to get the Takegawa 305cc big bore kit, which gives you just over 10 horsepower extra push.

Why should you not upgrade using the 300r parts?

Edited November 11, 2015 by Martin54

[Richard-BKK]

The main reason to use a Takegawa 305cc Big Bore kit is that it's cheaper, less difficult to install and offers more performance. The Takegawa 305cc Big Bore kit is made in Japan and upgrades the Honda CBR250R to “real” 305cc and not the 286cc of the Honda CBR300R.

The Takegawa 305 Big Bore kit comes with everything you need to upgrade your CBR250R, without the need to split the engine to replace parts for modify the stroke.

With the 305cc big bore kit the Honda CBR250R will have a shorter stroke than the CBR300R, with real 305cc. It will change the Honda CBR250R engine in a real high revving sportsbike with more power and torque. The Honda CBR250R with 305cc big bore kit makes 34.2 horsepower on the dyno, while a Honda CBR300R just hits 27.1 horsepower on the dyno. See the attached PDF file for the details... (red line is with 305cc big bore kit....)

Still the whole big bore kit cost around 35,000 THB.

bore_up_cbr250r_graph.pdf

Edited November 11, 2015 by Richard-BKK

[Happy Grumpy]

Saw a thread on a forum where someone's engine blew up.

He was using the Takewhatever 305cc kit.

I haven't seen any info on other cbr250/286 engines blowing up.

[Martin54]

Thanks for the reply Richard

I ask because my engine blew the other week and my bike is actually getting converted to 286cc at the moment. I was a little worried were people running into issues. I paid 25k for 286cc and was quoted 36k to take it up to a 325cc.

[papa al]

Richard,

Thanks for linking the dyno grafts.

Very colorful.

Hard for papa to interpret though, as can't read Japanese.

In the 250==>305 conversion to 34HP,

is changing exhaust and fuel delivery controller also required?

As for engine failures, if you modify for hi revs and power, expect declines in reliability.

Edited November 12, 2015 by papa al

[DLang]

Thanks for the reply Richard

I ask because my engine blew the other week and my bike is actually getting converted to 286cc at the moment. I was a little worried were people running into issues. I paid 25k for 286cc

Wow

There's the part numbers needed in the CBR250 thread.

The total cost for all the parts is 8,xxx baht.

10,xxx baht would be a more realistic price. Just order the parts with the part numbers listed, and organize a decent mechanic to put them in for 2k baht.

[Martin54]

Maybe 8,XXX if you have a fully functional engine but as I said I blew mine the other week.

Quote for 250 parts from honda was 19,XXX, so with the included custom ECU I don't think I am getting ripped off.

Also, I think the mechanic also works for honda racing.

[papa al]

Thanks for the reply Richard

I ask because my engine blew the other week and my bike is actually getting converted to 286cc at the moment. I was a little worried were people running into issues. I paid 25k for 286cc and was quoted 36k to take it up to a 325cc.

Why did it blow?

[Martin54]

Thanks for the reply Richard

I ask because my engine blew the other week and my bike is actually getting converted to 286cc at the moment. I was a little worried were people running into issues. I paid 25k for 286cc and was quoted 36k to take it up to a 325cc.

Why did it blow?

Laos

[papa al]

UXO?

[Martin54]

haha!

the bikes a cfr250l,

pretty sure this was the cause anyway

[papa al]

'Some of them want to abuse you.

Some of them want to be abused'

[Happy Grumpy]

What part(s) of the engine 'blew'?

[Richard-BKK]

Richard,

Thanks for linking the dyno grafts.

Very colorful.

Hard for papa to interpret though, as can't read Japanese.

In the 250==>305 conversion to 34HP,

is changing exhaust and fuel delivery controller also required?

As for engine failures, if you modify for hi revs and power, expect declines in reliability.

8,000 or 10,000 THB would be very unrealistic for upgrading a Honda CBR250R to a CBR300R with quality products. The original Honda CBR300R cylinder (286cc) already cost over 12,000 THB. And this is without a CBR300R piston kit...

Of course you need a few parts more to change a CBR250R to a CBR300R, parts like crankshaft and conrod assemblies are needed… as the Honda CBR300R has a different stroke. Even some other small parts are needed… lets say it simple Honda made it especially difficult to use parts from the CBR300R on the CBR250R.

If you ask people who know anything about motorcycle modifying, they know Takegawa as a supplier as high quality engine upgrade products… Of course some low-cost manufacturers also know that and try to sell Takegawa imitation / copy products.

For the Dyno sheet, the red color is the dyno specs as for the Takegawa 305cc Big Bore Kit, which include everything in the picture. The green color is everything in the picture without the 305cc big bore set (cylinder and piston), and Yellow is everything without 305cc big bore set and fueling modification kit. Blue is the standard Honda CBR250R.

[Richard-BKK]

O by the way the Takewaga 305cc Big Bore Kit is also available for the Honda CRF250L and CRF250M....

[Happy Grumpy]

8,000 or 10,000 THB would be very unrealistic for upgrading a Honda CBR250R to a CBR300R with quality products. The original Honda CBR300R cylinder (286cc) already cost over 12,000 THB. And this is without a CBR300R piston kit...

Of course you need a few parts more to change a CBR250R to a CBR300R, parts like crankshaft and conrod assemblies are needed… as the Honda CBR300R has a different stroke. Even some other small parts are needed…

The Thais say this is the parts list:

And show pics from the parts manual here:

http://www.thaivisa.com/forum/topic/406414-honda-cbr-250r-2011/?p=9906783

Do feel free to prove this is wrong with a list of the parts you say is needed (from the CBR300 Parts Manual) with their price, as stated by Thai Honda.

Edited November 12, 2015 by Happy Grumpy

[Martin54]

I hope your wrong HG,

Can anyone do a better job than google?

The parts list is off thier FB page, get my specific parts list tomorrow

Edited November 12, 2015 by Martin54

[Richard-BKK]

You can easily compare the two motorcycles for parts you need...

The Honda CBR300R http://www.bikebandit.com/oem-parts/2015-honda-cbr300r-crankshaft-piston/o/m156899sch908167

The Honda CBR250R http://www.bikebandit.com/oem-parts/2013-honda-cbr250r/o/m154749#sch793515

And if you think the parts look the same, think that just a little different specs will make it not work....

[Happy Grumpy]

Same parts for many of that.

Not that it matters too much as they're so cheap.

Of the 3 'expensive' parts the piston pin is the same.

Just the Crankshaft and Piston at $260 for the two, are different.

8,xxx baht for that swap over looks about right.

Edited November 12, 2015 by Happy Grumpy

[Martin54]

Same parts for many of that.

Not that it matters too much as they're so cheap.

Of the 3 'expensive' parts the piston pin is the same.

Just the Crankshaft and Piston at $260 for the two, are different.

8,xxx baht for that swap over looks about right.

Are you comparing the two bikebandit links? I am more concerned with my specific case.

This is my interpretation

1. Crankshaft

2. Throttle body

3. Camshaft

4. ???

5. Oil?

6. Clutch Springs

7. Cylinder head

8. ???

9. Cluch disks

10. Piggyback ECU (custom mapped btw)

[papa al]

For the Dyno sheet, the red color is the dyno specs as for the Takegawa 305cc Big Bore Kit, which include everything in the picture. The green color is everything in the picture without the 305cc big bore set (cylinder and piston), and Yellow is everything without 305cc big bore set and fueling modification kit. Blue is the standard Honda CBR250R.

Cool.

So with an appropriate muffler, maybe over 34 HP.

[DLang]

Going from 24 or whatever to 34HP, would it not also be best to upgrade the brakes and suspension.

Upgrading to the stock 286cc parts kind of makes sense if they are an easy fit. The 24HP 250 is a vibey little single cylinder as it is, the 286 version has a bigger counter balance to counter act the more vibrations. Pumping the little 250cc up to 34HP with nothing else upgraded seems a bit silly when there are decent bikes available with 34hp already out there.

[Martin54]

Going from 24 or whatever to 34HP, would it not also be best to upgrade the brakes and suspension.

Upgrading to the stock 286cc parts kind of makes sense if they are an easy fit. The 24HP 250 is a vibey little single cylinder as it is, the 286 version has a bigger counter balance to counter act the more vibrations. Pumping the little 250cc up to 34HP with nothing else upgraded seems a bit silly when there are decent bikes available with 34hp already out there.

thanks for your input

[DLang]

My input is always greatly received, usually with a deep moan and wide loving smile, but we shall hope that wasn't the case this time.