Old CB77 Racer Help Needed

[e3steve]

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Motor is a 62 (?) with breather tower

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'61. The upper casing is documented as being redesigned after engine nrs CB72E-113068 & CB77E-111030, both during the '61 production run. Not nitpicking, just putting the topic info straight.

[teazer]

No worries Steve. I did have a question mark in there because I couldn't remember the date of that design change.

Thanks for the correction.

[teazer]

As far as spacing between the carb and head, I know 26mm Mukuni's don't work on the superhawk's because they need additional space in the manifold to atomize the fuel properly. I only ask because I have those exact same carbs essentially bolted directly onto the head (stock manifold), and they function well. It got me wondering about the science at play here. Sorry if I'm staying off topic of the thread.

With 4 stroke Bleed type needle jets Mikuni usually atomize fuel better than Amals which had a reputation for large fuel droplets. We use 26mm Mikunis on a 240cc CB160 and with the two stroke type primary needle jets, we had very high unburned hydrocarbon levels. What that meant was that the ratio of fuel that burned to air was right, but there was some unburned fuel. We changed to a bleed type nozzle and that seems to work fine now.

Aftermarket parts were finned and long because they looked cool. I don't think there was a whole lot of science there. What i suspect the builder was doing was to add intake length for a tuned length.

[teazer]

Hi John,

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Front hub certainly looks like GT750 Suzi - common 4LS brake for that sort of application. Backing plates are a mystery, some repro Honda 4ls backing plates came out of SA in the 90's. Those are certainly made to look a lot like Honda ones..
Ray

Mr Jerry may be the man you are referring to.

I do recall an altercation with someone at Amaroo one year when he told me that the hubs were cast in SA in 62 and that he had the drawings from the period. When I cast doubt as the veracity of that claim he threatened to put me through the fence. I thought that was an interesting response.

[GORDON BROWN]

Hello

You certainly have a nice bike there, any of the racers / modifiers will know how much work has went into it from the pictures. One thing I wondered if you have checked how many gears it has ?
possibly you have a 5 speeder in there. Looking at the reversed shift reminded me that the Nova 5 speeders (except the very early ones ) are made so the reversed lever makes a std. shift pattern.
I hope this makes sense and you enjoy the bike.

Gordon

SAFOJ

[jerry]

Dear All, The double sided brake issue always brings a smile to my face and the issue still raises its ugly head here in OZ at various times. To keep everyone at bay I run one of our home cast brakes on the 350 and a Suzuki hub on the 500. I can tell you now that the bike on this thread has a home cast hub that would have come via Bill Snelling after we had sold the bikes and parts in 88 I think. I believe the patterns ended up with Mr. George Barber. Jerry

[e3steve]

I just knew you'd come up with a gem or two, Jerry!