Increasing Horsepower on a CBR600

**Smorg** · 13th July 2005, 13:19

Hey guys just chasing advice on what i would need to do in order to pull this off? I have already done the custom exhaust side of things but i'm kinda stuck as to what to do next any help would be appreciated!

**madboy** · 13th July 2005, 13:22

I'll give it three posts (including mine) before someone makes a comment about "Why buy a [insert brand in here] you shoulda just bought a [insert rival brand that poster happens to ride/want to ride here] in the first place".

No brilliant ideas from me, but nice bike and welcome to the site.

**Brian d marge** · 13th July 2005, 13:29

Originally Posted by Smorgen

Hey guys just chasing advice on what i would need to do in order to pull this off? I have already done the custom exhaust side of things but i'm kinda stuck as to what to do next any help would be appreciated!

Cam timing ,is critical on those ,,and then balancing the carbs ,,, then or should I say first ,,,make sure Everything else works chain , linkages u name it

After that you are into the spending money dept ,,,,

BTW the dimensions of the original Honda cans ( F2) are prety good , they just weigh a ton)

Stephen

**Zed** · 13th July 2005, 13:42

Originally Posted by Smorgen

Hey guys just chasing advice on what i would need to do in order to pull this off? I have already done the custom exhaust side of things but i'm kinda stuck as to what to do next any help would be appreciated!

Did you replace to whole exhaust system or just the muffler?

Other options you may want to consider are to lose some weight yourself or buy a 1000cc?

**Pwalo** · 13th July 2005, 14:02

I really like the F2 but I think that you are probably better off buying a more powerful bike if that's what you're after. Certainly can't recall people who owned them complaining about this problem.

Can't see how you can make your bike produce a lot more power without major expense, or possible loss of reliability. Now a suspension upgrade would be a great idea.

Otherwise just follow the other posters recommendations regarding engine mods.

**Smorg** · 13th July 2005, 14:02

Would buy a bigger bike if i had the cash but alas i do not, the 600 is my first bike didnt f*#K about on 250's i've lost as much weight as i can.....and yes the bike weighs only a tiny bit less than a Suzuki Busa..........go figure

**Zed** · 13th July 2005, 15:06

Originally Posted by Smorgen

Would buy a bigger bike if i had the cash but alas i do not, the 600 is my first bike didnt f*#K about on 250's i've lost as much weight as i can.....and yes the bike weighs only a tiny bit less than a Suzuki Busa..........go figure

The Busa weighs in at around 215kgs dry and those early 600's weren't THAT heavy dude...anyway, the CBR600 has always been a great bike and as a learner it shouldn't spit you off if you treat it with respect.

Btw, now that you mention that it's your first bike IMO I feel that you're jumping the gun a bit trying to make it go faster!! Learn to master riding it at stock before you mess around with power modifications.

**TwoSeven** · 13th July 2005, 15:08

The F2 should pull about 90bhp at the rear standard - its good for 114bhp but will cost you and also depends if you still want to use it as a road bike or race bike.

First thing you should always do is make sure the shims are really accurate (it runs soft seats so you lost the tuning after about a week of wacking open the throttle). Chain and sprockets are the next most important and then timing (there is a little 'factory' adjuster you can get that some folks tell me makes a diff, although I havnt as yet tried it in mine.

Basic straight out of the box mod is the TTS 639cc big bore kit. Will also require a gasket set to be purchased. While you are at it, purchase lighter rods and get the crank lightened and balanced.

Blueprinting the engine (especially the shims) will give 5bhp and so will adding a fancy chain n sprocket. It doesnt really need gas flowing. The standard headers are the best for it, but the end can will need to be replaced with a higher flow unit - but as mentioned use the same dimensions (Harris in the UK used to race them so might be able to offer some advice on tips n tricks).

Then you'll need to change the carbs and rejet (it was standard to put on the keihin units) with a k&n filter but no other airbox mods. I still like the original mikuni's tho - they are slightly harder to mod because the needle is fixed into the slide and needs to be completely replaced.

Then if your feeling fancy go for the liner gearbox (straight cut) and HRC mild grind cams/springs/valves and valve seats as well as a better rad - I think they also offered a better oil pump. I'm not sure if anyone does an aftermarket gearbox anymore, you may end up having to take a look at HRC.

You lose a bit of power due to oil drag in the sump, that problem was fixed in the F3 (but those engines were rubbish for tuning) - personally I found that if I used a very light oil (5-20) I got round it, although you'll probably not notice it running a modern 10-40.

You can lose about 8kg of weight by removing the center stand, end can. For road use, i'd also get a new fairing and replace the lighting with fancier but lighter aftermarket stuff. Ditto with the wheels, the original were very heavy and make it heavy on the cornering (an easier fix is to put on longer clipons for the leverage).

Rear shock goes for an ohlins unit (they aint that expensive for that machine) and you need to either replace the front forks (WP Roma) or completely re-work them since there is no rebound.

You can get it down to 160kg dry which is lighter than the latest RR.

If you get any headwork done - stan stevens or TTS are probably the best (there are a few tricks in that model with the valving that can cause grief).

**Smorg** · 13th July 2005, 15:56

I read up the the stats of the F2 through the haynes manual and the rest of it and belive it or not(i didnt) it weighs in at 205kg not sure if that was dry or not though......thanks for that twoseven and zed you have already increased my knowledge ten fold.
I find my cbr is awesome to learn on i rode my mates 250 ninja and was bored within 5 mins i think my bike is probably right for my skill base for now

the increasing horsepower question is something im looking towards in the future ie. next 7 months

**pete376403** · 13th July 2005, 17:18

Do all that stuff in TwoSevens post and your CBR600 now owes you about the price of a couple of new R1's. Second guessing the factories is never easy or cheap.

**TwoSeven** · 13th July 2005, 19:15

No its not that expensive come to think of it. Most of the bits are just bolt ons, anyone can do em - even the big bore kit aint all that bothersome as big bore kits go.

You could buy a new R1 of course, but then you'd have a bog standard bike that every other pleb has. To make it different, you'd still need to bung on all the bolt-ons which brings you back to your orgininal question.

Bolt-on bits are bolt-on bits - they cost the same no matter what bike you put them on.

205kg sounds a bit much and would be the top end of wet weight. Mind you the bits are center stand and lights and full fuel tank.

If it is your first bike, dont mod it just yet. You've got a way togo before you'll notice the difference - F2s are quite hard to ride hard compared to a modern 6.

**WINJA** · 13th July 2005, 19:20

TURBO AND NOS

**gav** · 13th July 2005, 19:40

pffft, save ya money, buy decent tyres and get ya brakes sorted, new fluid, pads etc etc. Go do some track days and have some fun. In 18 months time start thinking about mods, cheapest option maybe a later model F3 engine or a big bore kit and carbs. (Or trade it on a later model GSXR600)
Oh, and welcome to KB

**Jonty** · 13th July 2005, 19:49

It is interesting reading this as I have the F3. I think from memory mine is about 110hp and to be honest the only problem with power is you can't mono off throttle alone (unless you are going up hill!!) Other than that they feel a bit light in down low torque and great around 10 -12K, I would never consider powering it up as the bloody thing would have me for breakfast. I have always believed that if you are not Mr Rossi and you feel the need for more power in a sport 600 you are probably not riding the bike to its full potential, but I could be wrong

**WINJA** · 13th July 2005, 22:30

Originally Posted by Jonty

It is interesting reading this as I have the F3. I think from memory mine is about 110hp and to be honest the only problem with power is you can't mono off throttle alone (unless you are going up hill!!) Other than that they feel a bit light in down low torque and great around 10 -12K, I would never consider powering it up as the bloody thing would have me for breakfast. I have always believed that if you are not Mr Rossi and you feel the need for more power in a sport 600 you are probably not riding the bike to its full potential, but I could be wrong

YUP YOUR WRONG