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HONDA CL350 1972 PERIOD 4

Firstly let me say from the outset that I am no bike mechanic or aficionado of bike brands & or models so please forgive me for the mistakes that I am bound to make in this article.

I started racing a few years ago on a 250 Bultaco that my brother in law Lex Dreier also a Goondiwindi local & I built ( mostly Lex ) out of a Bultaco Alpina & assorted other bits & pieces. After learning the ropes around the Warwick & Stanthorpe tracks I decided to find something a little quicker.

( yellow version at Morgan Park Warwick)

I purchased my CL350 from Lyle Sara who had raced it at Warwick for at least a couple of seasons. Lyle built it from scratch using as far as I know Eric Kalamaja‘s “How to build a Honda CB350 Vintage Road Racer” as a guide.

The specs on this machine are as follows. 1972 CL350 originally a 325cc machine, bored out to 66ml to take larger Kawasaki pistons that takes it out to 348cc. Tigh cam, shaved head, enlarged exhaust ports & inlet ports to take twin 34ml Mikuni round slide VN series carbis. Hagon rear shocks, welded frame, electronic ignition, 500/4 front end, Susuki 550 front tubes & hubs, runs on standard unleaded fuel with 210 main jets. Tyres are Dunlop TT900’s & has a 5 speed gearbox.

When I first started racing the Honda I was running a 15 tooth front sprocket with a 37 rear which was fine until I learnt to handle the machine & started looking for more top end particularly half way down Warwicks main straight. I now run a 17 tooth at Warwick & drop back to a 15 for Stanthorpe.

The bike basically went OK for a season or two, I did change the exhausts from the originals that were both on the LHS of the bike, to a pipe down each side, I had the new pipes made up locally but reused the originals megaphones. Probably not the best idea for ground clearance but I haven’t scraped them yet,!!! I liked the look of the twin pipes & it did solve the problem of having very hot exhausts just under your left thigh.

Another change that I have made recently which I would strongly recommend to anyone building a Honda racer is to fit needle roller bearings to replace the original camshaft end covers. In my experience they have a habit of wearing particularly on the LHS causing the seal on the cam shaft to leak profusely, needless to say it is not a good thing when your cam shaft can move up & down a couple of mil & we know how much we all hate oil leaks.

( Photo courtesy of Kevin John )

Another problem I have had to fix is a gear box problem that was causing no 5th gear, random false neutrals & eventually it would drop back gears when you throttled off. This occurred several times one day when I throttled back at the end of the main straight at Warwick, locking up the back wheel. Not something I would recommend you do if you can help it. The false neutral problem had been happening for a while when using the starter, you would select top gear but when the starter hit the back wheel it would find a false neutral & if course just spin the back wheel. I’d realised what was happening & then drop it into top gear with a “hell” of a crash. We pulled the gearbox down expecting to find bit & pieces everywhere but the gears look fine. Turned out there is locating pin in the bearing at the end of the primary shaft that stops the shaft from shifting sideways. This pin had been pushed up through the side case coming out just above the front drive sprocket. There had been a small oil leak there for some time that was conveniently oiling my chain, so we pushed the pin back into place, welded up the crack & the gearbox was as good as new. Other competitors have told me this particular type of Honda gearbox is really tough & after this I totally agree.

Having now pulled out the motor about 10 times ( current record is 35 minutes ) I have learnt a lot about motors & motor maintenance since I first stared, still very much a novice but I have learnt a few things over that period “not to do”. Don’t use just any type of gasket sealer particularly on the head as in the end when the head leaks oil after you arrive at the track for a weekend meeting it is just not worth it. Don’t change the main jets without first either removing the slides or at least pulling the throttles wide open. It’s a great way to bend your needles if you don’t. Experienced racers will probably cringe at some of these mistakes I have made over the last few years that have cost me valuable track time but I have always believed the easiest person to laugh at is yourself.

Another real “no no” that I certainly am not alone in doing is tyre pressure stuff ups. At a recent Stanthorpe meet I was interrupted while checking my tyre pressures ( that’s my excuse ) & went out on the track with about 30psi still in each tyre. Coming out of the turn into the main straight my back tyre was skipping around the corner & my mates watching right next to the corner kept commenting about it but I still didn’t click what was wrong until much later in the day. Believe me, correct tyre pressure, I normally run around 18psi front & rear “is” very important to staying upright. Again, 18psi might not be the right tyre pressure but I’m dam sure it’s a lot safer then 30psi. Another competitor recently told me to verify your tyre pressure is correct check it just before a race, then check it post race as soon as you get off the bike & it should rise by about 4psi if the pressure is correct.

 

( Rusty Pierini & myself battling it out at Stanthorpe as usual )

Finally to anyone out there that would like any assistance on setting up a new bike please give me a call on 0412 717929 or
email david-vincent@bigpond.com. If I can’t help I will certainly be glad to point you to someone who can.

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