The International CBX Owners Association

Good stuff Mike, thanks.

norzilla wrote:Just to shine a little light where light is deserved. Hugh Robinson from Robinson Precision Engines in Bathurst, NSW in Australia is the go to guy for building monster size and power CBX motors. I have just had him build my 1425cc CBX motor for the cafe racer I built. The motor runs a set of CR Smoothbore, PowerArc ( triple spark) Ign, Hydraulic clutch conversion, custom alloy rods, ceramic coated pistons, custom pipes, custom cams, fully ported heads etc etc blah blah. The motor will make well over 200hp when dialed in. I just need to replace the clutch I fried doing a few initial power runs on the dyno while doing the base set up on the motor.

Is that a stock oil cooler?

I believe it was Mike Nixon who said something like: "A CBX is liquid cooled. Unfortunately, that liquid is gasoline."

Going back to EMS' notion that a CBX can't be made to make 200 hp, perhaps it can, for short periods, on non-standard fuel, and not having to meet any emission requirements. A long time ago, I started doing my homework to hotrod a CBX. After talking to a lot of folks who'd done it, I bought the CBR-XX. Have not regretted it.

Rick Pope wrote:I believe it was Mike Nixon who said something like: "A CBX is liquid cooled. Unfortunately, that liquid is gasoline."

Going back to EMS' notion that a CBX can't be made to make 200 hp, perhaps it can, for short periods, on non-standard fuel, and not having to meet any emission requirements. A long time ago, I started doing my homework to hotrod a CBX. After talking to a lot of folks who'd done it, I bought the CBR-XX. Have not regretted it.

HAHA! I love my CBX, LOVE it. But as a motorcycle to RIDE it doesn't hold a candle to the modern bikes. Even with my mods and good parts, it turns like a truck, accelerates somewhat, stops after a bit, etc. Doesn't get in the way of me loving it, but I doubt I'll ever travel on it.

Rick Pope wrote: Going back to EMS' notion that a CBX can't be made to make 200 hp, .

See, that's the thing! I never said that! Here is what I said:

with 1300cc and a compression ratio of 10:1, you are NOT making 200hp.

I wish people would read and really understand what I say. Maybe it is the language barrier...me being German!

NobleHops wrote:

Rick Pope wrote:I believe it was Mike Nixon who said something like: "A CBX is liquid cooled. Unfortunately, that liquid is gasoline."

Going back to EMS' notion that a CBX can't be made to make 200 hp, perhaps it can, for short periods, on non-standard fuel, and not having to meet any emission requirements. A long time ago, I started doing my homework to hotrod a CBX. After talking to a lot of folks who'd done it, I bought the CBR-XX. Have not regretted it.

HAHA! I love my CBX, LOVE it. But as a motorcycle to RIDE it doesn't hold a candle to the modern bikes. Even with my mods and good parts, it turns like a truck, accelerates somewhat, stops after a bit, etc. Doesn't get in the way of me loving it, but I doubt I'll ever travel on it.

And that is part of the reason why I love the "old school" bikes. FWIW, I do travel on them - 400 mile days, 1000 mile weekends.... Maybe not a C2C excursion, but some good, fun miles. I don't know what I MAY be missing, but maybe it is good that I don't know!!

Steve

Rick Pope wrote:I believe it was Mike Nixon who said something like: "A CBX is liquid cooled. Unfortunately, that liquid is gasoline."

How true!!!
Only recently I did the same ~500 Km first on the CBX and then in my (yet not fully run-in) BMW 118i car.
CBX ~270 Kg, 105 HP, riding type: spirited, fuel consumption: ~9.1 lt/100 Km (31 Imperial mpg)
BMW ~1400 Kg, 172 HP, driving: relaxed, fuel consumption: ~6.1 lt/100 Km (46.3 Imperial mpg)
But guys, if I had to do the same 500 Km trip all over again, we all know which vehicle I would choose - Any time.
Q: With so much gasoline cooling why do we need an oil cooler?

Syscrush wrote:

norzilla wrote:Just to shine a little light where light is deserved. Hugh Robinson from Robinson Precision Engines in Bathurst, NSW in Australia is the go to guy for building monster size and power CBX motors. I have just had him build my 1425cc CBX motor for the cafe racer I built. The motor runs a set of CR Smoothbore, PowerArc ( triple spark) Ign, Hydraulic clutch conversion, custom alloy rods, ceramic coated pistons, custom pipes, custom cams, fully ported heads etc etc blah blah. The motor will make well over 200hp when dialed in. I just need to replace the clutch I fried doing a few initial power runs on the dyno while doing the base set up on the motor.

Is that a stock oil cooler?

No not a stock Oil Cooler, it is an after market and about 30% bigger in cooling area, by my calc. It sized up for UK weather cond, but not the bike and I are in Australia so will prob need to upgrade again.

all good gents, and non believers still putting out over 220 hp at the back wheel
larger oil filter was fitted as we new we would need
goes hard.. still more mods to do
but as I said before horse power is only a question of money..

That must be so much fun to ride.
Looks good as well.

It's a gorgeous bike, and I am delighted that you were not put off by the questions and skepticism. Please continue to post pics and keep us updated as you go Steven, we are all junkies for the details.

N.

He could sure silence the skeptics by answering some of their questions and explaining some details instead of just posting pictures.
220hp on the rear wheel are around 245hp on the crank.
I am as interested as anyone and I do not question the talents of the engine builder, but I have masters in mechanical engineering and my thesis was performance increase on an internal combustion engine and I have seen my share of horsepower shootouts and still wonder how you get to this output level with a naturally aspirated engine and a compression ratio as he stated. Sorry.
What do our friends at CBXWorld have to say? They are much more familiar with getting performance out of a CBX motor than we are. If they buy it, I will too.

Having been around these things since they were new, and seeing countless engine mods in search of more HP, some done by quite capable individuals, I must also admit to being skeptical of 220 RWHP. Like Mike, it would be great to hear more detailed information on just how this enormous number was reached.

I see nothing so far that I haven't seen or heard about before, including the trick of cutting and rewelding the intakes for a straight-shot intake charge. This mod is worth quite a few HP, but has been done many times before. Radical cams, shim-under-bucket valve train, bigger valves, etc are all great mods, but have all been done before as well and none of those engines even approached 200 HP. What I recall with the best of those mods previously is about 125-135 HP. Now that wasn't with the huge overbore described here, but with a more acceptable 1150cc bore. I'm still finding it hard to believe nearly 100HP hides in just that extra 200cc.

As also noted, a stock or close-to-stock CBX clutch would NEVER handle 200HP - it barely handles 85HP.

That said, I'd love to see a couple of bone-stock CBXs run on that dyno to see what it shows their output to be. We KNOW what those numbers should be.

I'm extremely interested in what other 'magic' this engine builder has up his sleeve that countless other quite capable guys haven't been able to find in the last 35 years.

In the end, if it makes 220 HP, it makes 220 HP. Just relaying 35 years of experience with these things.

Dave

It's easy to label people who do not just accept anything unchallenged as naysayers, but let's look at some of the basics:

First, you don't make horsepower. You make torque. Horsepower then calculates out of torque and rpm.
That tells you how to achieve high horsepower: Increase torque and/or increase rpm.
European engine builders historically make hp out of rpm and U.S. engine builders used torque.
How do you make torque?
You increase the pressure above the piston during combustion.
You can achieve this by increasing the volume of air the engine takes in and increasing the compression of that volume and using a different fuel than gasoline.
Increasing the valves, eliminating the restriction in the intake canals, changing the cam profile to a longer opening cycle, increasing the compression ratio, running alcohol (or similar).

After you have done all that, you need to take care of your mechanical components under the piston to make sure they take the hp.
The CBX crank is a weak link when you go to 200hp.

I love to hear a good story, but....

EMS wrote:First, you don't make horsepower. You make torque. Horsepower then calculates out of torque and rpm.

The physicist in me really wants to argue this, but no good will ever come of it.