Honda CB72 1962-65



This bike was the first CB72/77 racer I built to race in Australia to comply with the pre-62 Classic rules.  It is fully MA legal.  

It has morphed over time into a very fast and very successful race bike and it was developed into a consistent top five finisher. It runs a full 350cc and is fully developed to runs on methanol for even more power. It was last raced in 1990 before I moved to the US and it was rebuilt completely for sale.  The motor was freshened with new pistons and a valve job and the valve springs were replaced, on one of my trips home to Australia and it will be fully checked prior to delivery. It will be supplied with a new battery and it was ready to race or parade or to add to a collection.

The chassis was stripped and powdercoated black, alloy was polished and everything checked and replaced as required.  

It was sold with a few spares and full range of front and rear sprockets, main jets, needles, needle jets and slow jets for methanol and for petrol..

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This is where this bike has spent most of it's race life - close to the front of the pack and has rarely finished outside the top ten at Winton, Calder, Broadford, Phillip Island or the odd trip to Oran Park. It usually finished in the first three in pre 62 350 races.

Notice the three Manx Nortons and an AJS 7R following close behind and that's usually where they finished (but not always!).  Beaten regularly by a couple of better riders and the odd cheater with a 450cc+ BSA B31 or a 600cc Manx. 

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In this picture taken almost half way down the course at the Geelong Sprints, we are holding station against the 650cc T110 of the late David Drechsler.  He pulled away to win, but that's  almost twice the capacity and he was a great rider. 



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Stock 54mm (CB72) pistons were replaced with custom liners and custom 64mm pistons for higher capacity, higher compression and a lot more power. Crankcase mouths were opened up for the larger liners Shown for comparison are a Henning CB350 piston, a Wiseco for a KZ650 and a stock 60mm Honda CB77 piston.


New pistons and rings have been fitted.

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Over the years, it has been run with cylinder heads ported by Superbike racer and mechanic John Kaiser and tuner Peter Van Meurs of Proflow in Geelong as well as by Karel Morlang who passed a way a few years ago. It has also run with a mildly modified head through different shapes of squish bands.  

It has and now has a fresh head with the latest version of the squish design which makes for incredible acceleration out of corners.

This picture is just one of earlier cylinder heads.

It had oversized custom valves at one stage, but they lasted about 2 races each, and have been replaced with lightened stock valves which make for better punch out of corners without losing any top end rush. Valve springs are R&D and valve caps are titanium.  Springs are shimmed for correct length and tension with custom spring seat shims. 

Rockers arms were lightened and never require attention. It also has light weight tappet  nuts.

Over the years we tried several different camshaft and valve gear arrangements.  Some were fast but fragile, others were just OK and one was really good. Norris T grind was great, but a little tame. Norris S and SS made more power but valve gear didn't last. The best cam for this motor was ground by Norris Barsumian, the founder of Norris Cams, and we now get them from Megacycle. Very high lift, moderate duration and great punch out of corners.

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For years it ran stock points on the camshaft, fitted with an extra spring and reground points cam to eliminate bounce at race revs.  

It has now been fitted with an electronic ignition from a Suzuki road bike.  The CDI is fitted up under the seat where it's invisible and the coils were swapped out for a pair of matching high output units from a more modern bike. The trigger is now crank mounted where it should be.

The mechanical tacho gear was removed and replaced with a modern electronic type in a custom anti-vibration mount.

The original tacho (TZ Yamaha, recalibrated) plus drive gears and new tacho cable will be included in the spares box along with the original points and stock coils.

Before it was sold, the ignition had another upgrade to a DYNA S on a custom machined mount.

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The crankshaft was lightened by the late Graham Bird who is missed by all who knew him. He stripped it and lightened it and pressed it together with a pair of super trick race kit big end cages. They have 20 individual rollers versus stock which has 11 pairs of rollers which rub and fail at race speeds. Race kit cages do not. 

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Transmission has been run with every combination of OEM gears including a C72 Dream top gear which made about a 1.5% difference but lacks the undercutting of stock gears. It has just been rebuilt with a perfect stock transmission and comes with a couple of spare sets of gears. 


OEM first gear is quite low and virtually guarantees the holeshot every time. Whoever said that "Races are not won in the first corner" obviously wasn't a racer! 


BTW, the clutch has a different clutch pack and never slips or grabs and has a set of super trick springs.


Gearshift has just been changed to race shift pattern with a reversed lever.  The street shift lever and linkage are included in the spares kit.


FInal change before it was sold was the fitting of a Nova 5 speed race gear set.  It was brand new and has never been run in a motor..

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Wheels are fitted with alloy rims, lightened hubs and backing plates, lightened cams and race linings. Front Rim is an Boranni WM2 (1.85") and the rear is WM3 (2.15"). 


The rim saver in the picture was fitted by one of my sons when he needed a good set of tyres for his street bike.  


The wheels were just stripped cleaned and checked and fitted with new fresh AVON race tires and new tubes. 

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Rear suspension by Koni, and features adjustable damping. The Shock bodies were specially machined to reduce spring preload slightly for better ride and handling. Last time I checked, parts were still available from Proven Products, the makers of IKON shocks. 


The bike comes with a spare set of alloy bodied shocks and several different springs. They are almost new but are sticky and should be rebuilt with fresh oil and seals.


The frame has been lightened and braced.  The swingarm has needle roller bearings and has custom bracing courtesy of Bob Martin Engineering.

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The tank is made of fiberglass by Birmingham Fiberglass in the UK.  I have a mold for that tank and can provide replacements too.


Seat was custom made to fit low on this bike's frame rails to lower the C of G for better handling. It was professionally covered and looks great. Style is closer to Manx Norton than RC162, but I like it.


The fairing is one of many copies of the Yamaha TD1 fairing used to launch a thousand race bikes over the years with a screen from the Racers Edge.

In a time far far away, when that race stand was fabricated, other racers used to joke about the training wheels.  Now ALL race stands come with wheels!   Talk about being ahead of the curve.


These pictures were taken fefore the last rebuild and delivery.


After those pictures were taken, the bike was completely stripped and rebuilt.  Frame was done in black powder coat, motor was rebuilt with the Nova 5 speed trasmission, carbs converted to petrol jetting, tank was cleaned out and sealed with a Caswell tank sealer and painted and so on before it was delivered to the new owner at a half way point - Albury Wadonga on a cold wet winter day in June.