CB1.5

[Kai Ju]

Hello all,
I haven't posted in a while and am still quite new here but wanted to share a pic and info on my '89 CB1.5
Why 1.5 you ask ? Because it has a CBR600F3 engine.
The forks and wheels are F3 as well while the rear shock is '93 CBR900RR with an ST1300 spring. The shock is about 4mm longer eye to eye which increases ride height by about 14mm.
Exhaust is a mix and match between F3 race spec headpipe and 919 ( 900 Hornet ) FMF muffler. Midpipe is of unknown origin.
Radiator is 599 ( 600 Hornet ) and the coils now reside where the thermostat used to be.
My first posts were me looking for a seat which I finally found in Japan, used.

Kai Ju

[mdula]

Sweet bike. Good job. What are the wheels and tires?

[mrbones]

That's one of a kind right there.

[Kai Ju]

Thanks guys,

The wheels are F3 with a 120/70-17 front and 160/60-17 rear.

As far as it being one of a kind I heard that this has been done before but haven't seen pics or specific info.

Is there an easy way to post bigger pics ?
If so I'll add some details of motormounts etc.

Kai Ju
 

[ptlcb1]

On the old HondaCB1.com website, which is no longer accessible, sad to say     there was a very clean CB-1 with an F2 motor in it.   I think the guy was over in Europe somewhere. 

[biker_king]

that looks good mate, was also thinking of doing the f2/3 engine conversion.

was the engine a strait drop in or was their any welding or frame modifing involved.

thanks james.

[Kai Ju]

was the engine a strait drop in ? No
 or was their any welding or frame modifing involved? yes

The only motor mount that lines up the is the bottom rear, everything else is different.
I inherited the bike from a friend of mine who had already made the front cradle and took care of the sprocket alignment which is critical with the F3 rear wheel and the engine placement.
I made the midmounts ( behind the cylinder head ) and the upper rear mount. I also mounted the 599 radiator and modified the F3 airbox to fit the bottom of the CB1 tank which also has to be modified.
From what I hear the original 600 Hurricane engine was based on the CB1 / CBR400 engine and allegedly drops in. But like I said, it's hearsay.
But I do have to say that all the work and effort was well worth it because this little bike rips, even with a 220 lbs rider in the seat. Second gear wheelies with a touch of clutch are no problem,
and I still get 40mpg commuting
It's a joy in the twisties with quick turn in and good straightline stability.

Kai Ju

[That_CB1_Guy]

Good job,
Shouldn't it rather be called a CB1.6 then?
 

[Kai Ju]

The CB 1.5 is in reference to the displacement increase.
If 400cc's = 1    then
   600cc's = 1.5

Kai Ju

[Drewski]

So what's it like then Kai ju

Vibey? Flickable? Front-heavy? I've got my pondering head on, should be plenty of CBR6 motors around

[Kai Ju]

It's very nice indeed.
The weight difference between the two engines is only 10 lbs so it doesn't really weigh all that much more, but obviously the horsepower to weight ratio is greatly improved.
Most likely the biggest handling difference will be due to the wider wheel and tire sizes and the dual disc in the front, additional unsprung weight as well as the rotational mass of the extra rotor.
It is still flickable though, especially since I raised the rear ride height 15mm with the '93 CBR900RR shock.
I get 40mpg on average and have power from 4000 rpm to 13500 rpm. It really comes on hard at 9000rpm and gets wicked at 11000rpm.
80 mph in top gear is 6500 rpm with 15/43 gearing.

Kai Ju


 

[baard]

Sweet indeed. If it wasn't for the fact that my bike is 20 years old and still completely original, that would be an interresting project.

One question though; How do you look for parts in Japan?

[Kai Ju]

One question though; How do you look for parts in Japan?
[/quote]

Friend of mine works for a Japanese company and was able to get me a used seat that I've since had recovered in a Carbon Fiber weave pattern. I'll post pics when it's not raining out and I can take some pictures.

[Kai Ju]

So what's it like then Kai ju

Vibey? Flickable? Front-heavy? I've got my pondering head on, should be plenty of CBR6 motors around

Hi Drewski,
Quick update, I've put about 3000 miles on the bike instead of taking it apart for painting and powdercoating like I originally intended. It's just been too much fun to ride.
I've also had a chance to put it on a dyno and was quite pleased. Mind you this is not a stock CBR600F3 motor but it showed 93 rear wheel horsepower and 42 ft/lbs of torque.
A stock F3 will do about 81 to 84, so I'm quite happy with the power this thing makes, no wonder it's so dang fast.

Kai Ju

[Drewski]

So what's it like then Kai ju

Vibey? Flickable? Front-heavy? I've got my pondering head on, should be plenty of CBR6 motors around

Hi Drewski,
Quick update, I've put about 3000 miles on the bike instead of taking it apart for painting and powdercoating like I originally intended. It's just been too much fun to ride.
I've also had a chance to put it on a dyno and was quite pleased. Mind you this is not a stock CBR600F3 motor but it showed 93 rear wheel horsepower and 42 ft/lbs of torque.
A stock F3 will do about 81 to 84, so I'm quite happy with the power this thing makes, no wonder it's so dang fast.

Kai Ju

Excellent No down sides then? If I ever get round to doing it myself, I might pester you for more info and pics if that's ok