CBX Racing

[steve murdoch icoa #5322]

I think it is very cool to even be around those legends let alone see them race.
Rick, feel free to post any more pics or stories you have about these racers.

[Warwick Biggs]

I raced Ago on one of his visits to Oz in the mid 70's but missed out with Surtees altho he did come out and do some classic races at Amaroo Park where he cleaned up on either a 500 Manx or a G80. Whatever, he was still very quick.

Both the PCRA and the owners of Phillip Island regularly sponsor the legends to come out and some are still very fast. Kevin Schwantz and Freddie Spencer come to mind most recently. I mentioned Maria Costello earlier and I could put up some flattering pics of her in her 'skins' but I know she would have another go at me if I don't explicitly get her permission to post them, sexist bastard that I am. Besides, this is a CBX racing blog, not a 'who I bumped into in the pits blog'. I get into enuf' trouble without going looking for it!

R.

[Warwick Biggs]

So here is some vision of the Castrol 6 Hour proddy race with Graeme Crosby on the CBX dicing with my old club mate Greg Pretty on a rather special XS11. Another club mate, Carl Hammersley was killed running it in in the Adelaide Hills after the lockwiring on the sidestand gave way, flicking him into the armco. So the dealer, Pitmans (who prepared the bike running a chain rather than a shaft!) gave it to Greg. The 6 Hour rules could be a bit odd at times.

https://www.youtube.com/watch?v=IHo0DiqXAys&t=256s

I'll see if I can find some vision of Surtees racing in Oz.

R.

[Warwick Biggs]

Found it. 1983 Amaroo Park. Surtees dicing with Saunders and Scaysbrook (partner of Hailwood in his successful come back on the Wynne prepared Ducati).

Surtees is so tidy. It is the second race on this video. A real cracker! I hope you enjoy it.

https://www.youtube.com/watch?v=Kmvtvjt2vWk

Sadly, Sydney lost Amaroo Park to suburbia as it was the home of probably the best production bike races in the world in the late 60's and early 70's

It was where the Japanese factories really developed their early road bikes leading to Honda's first production racer the CB1100R that incidentally, still dominates my Period 5 of our Historic class. It weighs 50 kgs less than the lump and produces 50 hp more but costs 6 figures to run. My race philosophy is cheap and cheerful by comparison.

R.

[Warwick Biggs]

OK, I've lost your attention with pics of great riders and CBX milestones so here is Maria...

[Warwick Biggs]

The lump is loaded ready for a ride day tomorrow at Mac Park. The Rickman seat has been professionally trimmed but I immediately had to attack it with a stanley knife as the grommets for the front P clip nuts were too small. It looked really schmik until then. Anyhow its idling evenly at 1500rpm which is about as low as you can go with the ported head and CR's.

It makes it easier to get up the ramp into the trailer,,walking it on the clutch - always a bit fraught. I will be glad when my new loading dock is finished and I can just push it in and out. Won't help at the track tho'. My trimmer trimmed over my new race numbers (06) so I had to undo half of what he did to get the numbers off and re-position them. All done and ready to take on the youngsters on their contemporary racers.

I want to experiment with the front end in readiness for the Hartwell Seniors in September. I need to find more ground clearance for higher corner speed. I have 20mm to play with at the front. Less on the Wilbers at the rear. It's a trade off tho'. The more I push the forks down in the triple clamps, the slower the steering. So I'm in search of that often elusive 'happy balance'. A life story there.

R.

[Syscrush]

GO GET 'EM!

What about dropping the forks and putting on wider bars? More leverage could help counter the slower steering, maybe.

Are custom triples allowed in your class? If so, you could get almost any combo of rake, trail, and ride height.

[Warwick Biggs]

Yes, Syscrush that is what I thought too and I originally fitted wide clip ons until multi Oz champ and successful CBX racer Trevor Manley suggested they were contributing to my early handling woes by feeding instability into the front over bumps and under hard acceleration and braking. He suggested taking my hands off the bars and holding them ever so lightly over the bumps and through the faster corners to see if it helped. It did. So he then suggested NARROWER bars. Changing the geometry by cutting off the steering head and bringing it back to 24 degrees helped even more and eradicated the notorious CBX wallow.

Incidentally, recommend this modification to anybody with a Prolink to make it handle like a modern sports bike. That is, if you can find somebody with the right jig and skills to do the job properly. Otherwise, buy a Firebade or an R1.

Now, if anything, it tends to drop into the bends a bit too quickly and I was planning to experiment with dropping the forks yesterday but yet again I had more serious problems to contend with. It was running way too rich off the bottom on cylinders 5 & 6 as indicated by a heat sensor on the headers. No.6 plug came out dripping (I'm running 8's). Hard to get 5 out without disassembling the oil cooler and pulling off the alloy frame lug so I put a heat gun on the plugs for 15 minutes. It helped and I got going again but every time I backed off the throttle to change down a gear it would lose 1 or 2 cylinders and then they would chime in again halfway through the corner.

Very disconcerting and hard to ride when an extre 30% of power kicks in suddenly while you are cranked way over. That is the one place you need a steady application of power to carry you through the corner with minimal changes to the dynamic motorcycle geometry. Without steady power in a corner you will lack rhythm and eventually crash.

So it fuels OK at full throttle but fouls the plugs at anything less. In other words it behaves like a dreaded 2 stroke! I haven't started pulling it down yet but I suspect either blocked slow jets or possibly gummed up float or seat on the CR carbs. Now, I do drain the float bowls after every meeting but modern fuels being what they are... I will report progress after I have a good look.

[Warwick Biggs]

I'm not sure if anybody is still interested in this taradiddle as I feel like the mad man talking to himself but some of the slow jets were indeed blocked. The mains and float needles are fine. My new alloy sprockets have also arrived from Vortex and they match my stud pattern, thanks Will Funke. Tomorrow I can look forward to the joys of trying to refit six CR carbs where there is only room for 4. I wonder if a triplet of twin choke side draft Webers would fit any better?

R.

[steve murdoch icoa #5322]

Rick, please keep posting on your efforts to get the performance of your bike sorted and your track day/racing exploits.
A lot of the questions you are asking or the info you are seeking is way beyond my mechanical abilities/knowledge. I suspect this is the case for a lot of us here.
It does not mean we are not very interested in your "taradiddle".

[Rick Pope]

I've greatly enjoyed reading of your adventures. Please continue.

[Syscrush]

I'm glad to hear that you got your carbs sorted out - your description of the behavior before clearing those jets sounds really scary.

What do you do for fuel filtration? Assuming that you don't wanna go through the agony that is a CBX carb re&re before every race weekend, maybe it would help to strain your fuel through a really fine filter before it ever goes in the tank. I guess it's still almost impossible to avoid ingress of sand or dirt at the track when you pop that filler cap open to refuel, though.

[Warwick Biggs]

Thankyou for the encouragement. The relentless problems in turning a 36 year old museum piece into a competitive racer and keeping it in top race condition can be exasperating.

This blog has turned into a bit of a diary of sorts and I have referred to it a couple of times when trying to recollect certain events. I do find the feedback useful as well, even if I end up wandering down a different path. And I hope some of the fixes I have found might help other CBX owners. I'm not Marco Polo and owe an immense debt of gratitude to Roly Skate and others who have developed their bikes thru' trial and error. So I am happy to share what has been shared with me unless there is a (rare) proprietary impediment.

The fuel problems relate to the additives in modern fuel. Under our racing rules I can only run fuel readily available at the pump. Methanol or avgas are not permitted in my class altho' the earlier periods can use methanol. Don't ask me why. So I run PULP or premium unleaded.

If the bike is left standing for any amount of time the fuel in the float bowls will eventually evaporate leaving a brown gummy residue. This will happen on any bike not in regular usage. It could be the detergents. I don't know. I'm not a chemist. In my case I do not run a filter or diaphragm or any other device that will restrict maximum fuel and air flow. So I have a note on my dash to remind me to disconnect the fuel lines. It would not be the first time fuel leaks down and into the combustion chamber past a partially closed fuel tap. At best it destroys the viscosity of your oil in the sump and you seize the motor or it could result in an immediate rod thru' the cases next time you try to start the bike. It is hard to compress a combustion chamber half full of fuel. That little diaphragm in the fuel line is essential on a road bike but not on a racer.

The passage ways and jets in a carburetor are fairly small and the slow or idle jets in particular have tiny holes that are easily blocked and if you are having trouble with the fueling on your bike it is probably the first thing to check after the filters in your tank or fuel lines. I have noticed that even when I check the float bowls and they look clean, if you spray clear carb cleaner in them you will still see a brown film emerge and with the slow jets you may need to test them by blowing or sucking air thru' after spraying with carb cleaner. It is even worse with the stock CV's as the rubber diaphragms in the carbs that smooth out the fueling and make the throttle light to operate can react badly to modern fuels as well.

Anyway, I'm not absolutely certain that my misfire was caused by blocked slow jets or that I have solved the problem but I will be surprised and disappointed if it turns out to be something else.

Here are a few more pics. Graeme Crosby, another talented Kiwi, CBX proddy racer and the first rider I ever saw regularly drifting the front wheel on a superbike and Michele Duff, the first Canadian (North American?) to win a GP - a rose by any other name...

DSCF1269.JPG

[NobleHops]

Priceless content Rick, please continue.

[Warwick Biggs]

First Bike.JPG

You might like to see in a nutshell how all this started. Here are some early indications...