CB72 racer

Had one of my dad's CB72 racers out to testfit a CR93 fairing that I have for sale, someone wanted to know how it would fit a CB72.



Fits it quite nicely I would think.
And then we rearranged some of the workshop, what meant that another CB72 came out of a dark corner, making me want to start this project.



Not with original tank and (replica) CYB seat as seen here, but with something more like a CR72 tank, period correct and with a lot of home made castings and other replica parts, and even some originals. As I have collected some CYB72 stuff over the years.
I have, or can build many of the small parts, the tank will pretty much be the only part I really don't have any idea of where to find or how to built yet.

CB72 freshened up

After last years season, the CB72 had its motor taken out because of a gearbox problem, and it pretty much sat at the end of the workbench for the whole winter.
A couple of months ago, my dad fixed the gearbox, and as we got the bike out of the corner, we did some slight modifications.
The rear wheel was swapped for one with an original hub, and a rim that matches the front. A front fender was made. (the dutch honda moped freaks might recognise it as a rare C320 fender) And the tank got some new stickers.

and the top yoke was swapped for one that has been welded shut and ground down to look like an original CYB yoke.

It is still a racebike, so it shows signs of use, but these little things just freshen the bike up a bit and make it look more like the honda's we all know from back in those days.

first event of this season

last weekend was the first event of this season, I didn't take the RSC90 though, this track was quite long and I want to give the S90 a good chance to have a smooth run in next weekend at Oldenzaal.
In Wolvega I rode the CB72 that I had some experience with last season and one of my dad's BMW's. This was the first time on a 500 BMW for me.
It took a bit of getting used too, especially the speed as I reached over 200km/h on the straight after which I had to brake hard for a 2nd gear corner. But I had fun with it.

picture thanx to Lea, CRT club photographer

No. 64 is me on the CB72, chasing a maico that I passed later on.

Again, picture thanx to Lea.

But I think this picture was taken just 3 corners before the CB72 tried to kill me....
The oil seal in the outgoing gearbox shaft worked itself loose, spraying oil over the right side of the bike, causing me to fall in the only right corner on the track.
Luckaly I could stand up without problems and pick up the bike. Only some bruises to my leg and back.
My ego was okay as this was clearly the bikes fault.

And this is what the CB72 looks like now, taken appart to straighten the front forks, new seal installed on the output shaft, footpeg straightened, but still some more work to be done before I can ride it again next weekend at Oldenzaal.

front brake

The CB72 is ready again for the event in Lelystad next weekend. I had some trouble with the front brake, Honda 200mm drums are too light, when really used, they grow so much from the heat that the spokes become loose. From one of my dad's other CB72 racers came a front wheel with Suzuki T500 front drum, now fitted with a honda brakeplate. These hubs have a thicker lining and can withstand the abuse of racing with modern tyres.

Racing at Purmerend

Last week we had an event in Purmerend at a closed off industrial area. I raced my 50 and my dad's CB72 to compete in 2 classes. This was the third event I rode the 250 to see if I would like the "big" bike.
Action shots are thanks to Lea langezaal, the club photographer, see more of her pictures on the CRT website
The number 2 bike is an Aermacchi.


Unfortunately in the last heat, the motor shot out of gear, or so it seemed, I was quick with the clutch, had a look if I could see anything wrong, but nothing to see. I tried to release the clutch gently, but that didn't feel right, so I quit.

Back home, we took out the engine, my dad has three of these bikes, and raced them with friends. Back then, the bolt that alligns the shift fork with the shift drum had broken before, so that was believed to be the problem. But when we opened the clutch cover, the real problem became all to clear: broken primairy chain.

This is a "normal" thing to happen to a CB72, especially when raced, but usually the chain cracks the cluch cover making it clear what happend, in my case it didn't even leave a scratch on the inside.
Fortunately my dad had a new stronger chain set ready to fit to this engine, just didn't get round to fitting it yet.