May 2000

From the outset this bike will not see any track time. I am putting it together as a "something different" club ride bike. My current ride is a 1933 Matchless CS Sports Tourer - 500cc single with twin exhaust ports, rigid backend, girder front end, 4 speed 'box with tank mounted gear change. The Honda will provide a softer long distance ride for events where I currently would not consider using the Matchless. A bike must be more than 30 years old to be club registered. One motor and frame are from 1968 and the other pair are slightly newer, so careful parts selection will allow club registration.

The bike will be assembled as much as possible from Honda CB250/350 twin parts I have accumulated over the last 20 years. Not many bits to choose from but enough exist to make one runner. There are two incomplete bikes to supply the necessary hardware. One is what's left of a roadgoing CB350 and the second is what's left of a Group D CB350 Clubman Road Racer.

The road bike will supply the frame, 12,000 RPM tacho, speedo and standard 350 engine cases, gearbox, barrels with new 1mm oversized pistons, head with 36mm carby ports and standard valves. The 36mm CV (Back & Front - stock carb on right) carbs are salvage from a CB500T.

The Road Racer will supply the modified cam (left is modified, right is standard), vented rear drum, CB 500T disk front end, and long petrol tank. The RR motor does not have the kick start fitted (or electric) or the generator rotor/stator and runs a total loss battery ignition, standard pistons and valves. I will keep all of this motor for spares. The lumpy cam is the only motor part I will use at this stage.

Standard Honda 350 Gear Ratios -
16/36, 83mph @ 8000rpm, 10.37 mph / 1000rpm, 5,780 rpm @ 60mph

Gear Ratios available -
17/38, 83mph @ 8000rpm, 10.37 mph / 1000rpm, 5,780 rpm @ 60mph & 108mph @ 10,500rpm redline
17/36, 88mph @ 8000rpm, 11.00 mph / 1000rpm, 5,450 rpm @ 60mph & 115mph @ 10,500rpm redline
17/33, 96mph @ 8000rpm, 12.00 mph / 1000rpm, 5,000 rpm @ 60mph & 126mph @ 10,500rpm redline

A few more shots of the remains -

Frame with tank and seat

standard tank beside the long tank

Spare cases

Cam shafts

The frame with the old and new tank / seat,
Munro rear shock absorbers
CB500T disk front end test assembled
CB500T 36mm CV carbie on the left and standard 32mm CV on the right
36mm port head on the left and standard head on the right

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June 2000

Fit brackets for tank and seat
Paint frame
Frame has been cleaned for inspection and painting. Steering damper bracket is a bit rough but that was how it was set up on the racer so I will continue to use it.

The tank / seat mounts have been worked out and will be fabricated in the next couple of weeks. Work will start on checking the front end and finding any missing parts.

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July 2000

The Honda rebuild has stopped - I am relocating from the city to the country over the next couple of months. My current empolyment comes to an end mid September and I have decided to seek a better life in a rural town not too far from Brisbane. Selling and moving the house is easy - relocating the contents of a 9 x 7.5m shed full of cars, bikes and spares is not something you want to do in a hurry. I have to be out of here by the end of July - so hurry it will be. It is going to take quite some time to sort out everything and pack it back on the shelves. This will be a long process as the contents of the shed will be in storage as I will continue to work in Brisbane while I tidy up my job and go to the new life for weekend visits. I have waited 20 years to get this bike running, another few months won't be a problem.

January 2001

I have settled in to my new job and am starting to get the sheds sorted out. The new workshop is 12m's wide X 9m's deep and I have a second shed plus a carport off the house. Just a little more room to move.

The frame is in for powder coating and I have started sorting out the best engine parts to use.

Found a new set of 35mm legs off a CB750F BolDor, however, the front wheel is a real problem - I would like to use a big drum but can't find anything suitable. The wheels found so far are cracked or in other ways beyond use. Still might have to go back to the disc brake - the BolDor uses mag wheels and a disc on the back so I can't use them. Still checking drum and disc brake wheels with spokes. The 32mm legs off the CB400N or SuperHawk (front dual discs / back drum on matching mags) could go on but everything has to be replaced and the stem will have to be reduced in length. I do know that the Suzuki GT750 twin disc front end (legs / spoke wheel) will drop in to the 500/4 triple tree I have - 35mm legs and correct wheel spacing.

My Engine spec's:
1mm oversize pistons - 336cc finished size
9.5:1 CR
Standard Inlet and Exhaust valves
Big CAM
Heavy Duty CAM chain
CB500T big bore CV carbs
Pretty much a standard motor

Not yet decided:
Carb - the CV's may not work with big CAM overlap. Possible replacements are from the CB350SL (smaller bore) or 32mm AMAL MK2's with 1.25" inlet stubs and 210 main jets.
Electronic ignition - dual magnetic sensor, full replacement
Exhaust - 2 into 1 or 2 single pipes - either style with reverse cone megaphones.
Lead acid battery or battery eliminator.

Other go fast stuff:
Use the CB500/4 gearbox with 24 tooth main shaft (17 teeth on the 350/2 and some 500/4's) Takes 1st much closer to 2nd to make a good close ratio gearbox, but will make fast getaways very difficult. To do this conversion you need both gear clusters from the 500/4 gearbox, the 500/4 clutch centre (fine spline), 500/4 clutch springs, 350/2 bearings / seals and the rest of the 350/2 clutch basket and oil pump.

Kawaka GPZ750 pistons. Take the engine out to 349cc and 11:1CR. Size is right but CR is too big for street use.

Suzuki GT750 front 4LS drum - if only I could find one in good condition.

Early CB72 rear drum. Good match for a big drum front (Suzuki 4LS) CB72 drum needs to be turned round to put the chain on the correct side and is cable operated so gives better choice for the rearsets. Other possible is Suzuki Titan 500 rear.

Tasks left to be completed:

Test assemble frame
Fit motor to frame
Wire up electrics
Test run
Register bike
Go on some club runs to iron out the bugs
Update Web Site with progress

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Start | Feb 2001 | March 2001 | April 2001 | May - September 2001 | September 2001 - March 2003
CB350 Engine specs | Final spec's | Detailed photo collection | CYB350's

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Contact Information

Electronic mail address
jmiller@brisnet.org.au

Web addresses
http://www.brisnet.org.au/~jmiller/
http://www.brisnet.org.au/~jmiller/honda
http://www.brisnet.org.au/~jmiller/matchless/
http://www.brisnet.org.au/~jmiller/hmccq/
http://www.brisnet.org.au/~jmiller/wolseley/

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