CBX Racing

[Warwick Biggs]

I am not entirely satisfied that lithium battery failure was the underlying cause of my recent DNF's on the Lump, so I'm making a few other changes, as well as ordering a new higher capacity LiFePo battery.

With the latter, I note that Antigravity now market a much higher capacity LiFePo that they designate 'heavy duty'. As well as over 700 cold cranking amps it has an over 100 watt hour capacity meaning it will not only easily start a high compression motor but should also be able to run the coils in a total loss system for normal race duration. They achieve this by deleting the battery management system built into most modern lithiums that are designed to prevent total discharge that will kill the battery. This means more capacity is available for deeper cycle or ampere hour consumption. But unfortunately, I can't easily get it in Oz and air transport of Lithiums is problematic. If anybody can help, I open to suggestions, but I digress.

It is also possible that I had or am having a partial failure of a coil or coils. The stock CBX 2.4 ohm coils are relatively high resistance items compared to modern pencil coils and the latter lower resistance coils will probably work better with my digital Ignitech ignition. They don't get as hot and therefore last longer too. I have learnt from past experience that the Ignitech does not like high resistance coils like the green Dynas that TIMS sold for CBX's. Nor will it run with a capacitor fed ignition system that produces a powerful but very short, albeit finnicky spark. That is fine because the Honda utilises an inductive or Kettering ignition system and I have never liked CDI going right back to the early 70's Krober on my TZ that sometimes caused it to start in reverse!

Nevertheless, b4 I start re-wiring for 6 individual pencil coils I am simply replacing the stock items with 3 new 2.4-ohm coils as well as new non resistive leads and caps. I reckon it is simpler just to replace these parts rather than attempt to test for an intermittent breakdown. As they wear I may move over to low resistance individual pencil coils that will potentially enable me to increase power by using the 'drag and drop' laptop tuneability of the Ignitech to experiment with advance and dwell on a dyno, harder to do (esp'y dwell) with the higher resistance coils.

As coils age and especially the older high resistance coils they get hot and the insulation on the primary and secondary windings starts to break down, especially under load. The fault can be difficult to diagnose or test for, other than on a dyno and still might be missed. They are relatively inexpensive items best considered consumables imo.

So new coils and leads and also a new starter solenoid (just in case, particularly after the half a practice day wasted identifying the sticky solenoid on the NC30 - also replaced).

Of course, I have cleaned and checked the fuel tank and lines as well as acquiring a VPW 0.75 litre sealed and filtered alloy crankcase catch tank that I am using to replace my 2 bodgied up plastic bottles that were fairly awkwardly and messily tucked into the ducktail. With this I can easily drain any excess blow-by oil in the pits at the end of the day without having to pull everything apart, simply because it has a tap. Crankcase pressure in a high compression motor can drain horsepower as well as springing leaks so it has to be relieved without spraying expensive 10W60 all over the back wheel. That is what those 2 blue pipes in the bike pics are doing.

Finally, I need to install a stiffer rear spring and check/lubricate the Prolinkage. Lifting the rear by extending the rear shock has changed the ratio of the linkage and the spring that was originally matched to my weight is now too soft. Lots of little things that might seem un-exciting but all add up to more speed and reliability. In order to finish 1st you have to first finish.

[NobleHops]

In awe of your persistence and determination, Rick.

[Warwick Biggs]

Thanks Nils. I learnt long ago that perseverance can make up for a lot of shortcomings and usually pays off in the end. I'm still improving my tennis too and when the literature says that there is not much improvement after 6 months from a serious stroke they are flat wrong. My tennis now is comparable to what it was when I was a kid playing every day altho' my fitness and flexibility is sadly, not the same.

I started the Lump up today after fitting the new coils and it fired up immediately despite a wintry chill and was idling strongly at 1,000 rpm which is encouraging. B4 it was inclined to stall at anything much under 1500 rpm. If it is not raining tomorrow I will take it over to the track and see if it will do a dozen laps without cutting out as it repeatedly did at my last outing.

[Warwick Biggs]

I managed a dozen laps between showers and by hugging the dryish racing line (that is not necessarily my line). I do not race the CBX in the wet. It is too heavy and easy to crash in variable conditions and I keep the NC30 for that. Racing in the wet; hopefully not crashing!

One punter asked too much of his wets in a heavily banked corner that dries fast and ended up with a visit to hospital after knocking himself out for over 10 minutes and giving the ambos a nervous time. Wet tyres are amazing as are slicks but neither work at all well outside their temperature parameters and you have to know what they are or you are better off with street tyres.

The Lump behaved itself this time and did not expire on me. I did manage to stall it on the dummy grid due to my own mistake and had to press the starter again but I purposely did not switch batteries and it was still sparking when I came in. I stopped to have a word with somebody on my way back and only then did I have to switch batteries as the new lithium could not manage a third start as well as a dozen laps but at least I now know it's limitations. If I could relocate the pulse generator to a camshaft or gear it down I could further extend battery capacity by eliminating the wasted spark. There remains a lot more that can be done to improve the ignition but then perhaps Nils was not flattering me by admiring my 'perseverance' in making a silk purse out of a sow's ear.

I have also been studying Jyo Bito's CBX catalogue and particularly his 18" Magtan magnesium wheels. At over $4,000 AUD they remain an expensive possible solution to the ground clearance issue.

[Warwick Biggs]

While I have the rear shock out waiting for a stiffer spring I thought you might like to see some pics of how we have lifted the ride height on the Lump.

Here is the standard Prolink top shock mount...

I have fashioned a rubber flap to protect the shock from gravel and track debris and here it is folded up and away so you can see the top mount.

[Warwick Biggs]

The bottom shock mount is also stock Prolinkage as you can see here...

[Warwick Biggs]

I'll try again. Here is the bottom shock mount...

[Warwick Biggs]

In this pic you can see where I have attacked the inner top arm of the Prolinkage with an angle grinder to widen it sufficiently to run a 160 tyre. I really need a 180 for more ground clearance but that will require a 5" rim to replace the 4.5" ZZR rim I currently run plus an entirely new, virtually unobtainable monoshock swingarm (unless I make it myself).

[Warwick Biggs]

Here is the arm itself... All fairly stock other than the toe protector on the lhs of the arm. This is required under our rules after ex works Suzuki rider and GP winner Oz racer Darryl Beattie lost his toes after falling off and getting his toes whipped into the rear sprocket by the chain. Ouch!

[Warwick Biggs]

Here is the fully adjustable Wilbers rear shock that replaces the prolink air shock. After taking it out I see that the spring is marked 59/59 - 220 - 130 meaning it is 59 mm diameter and I will need either a 140 or 150 to go stiffer.

Note the long rear dogbone (the threaded bottom). Originally the shock had the eyelet (bottom mount) an inch and a half higher with 6 mm of adjustment. I replaced that with a 15 mm longer dogbone that screws into the bottom of the shock and then I replaced that with a 25 mm longer dogbone chasing more ride height and ground clearance.

Roly thinks this is anathema and I just need to get off the bike more. If I could, I would but my 71 year old body is not of the same mind and so I have to lift the whole thing up to avoid ploughing the track. This is probably where EMS will chime in with "it was never designed for the track" and that my activities are just cruel and unnatural torture. In my defence all I can say is that when I started out with the Lump I never imagined I would ever be able to ride it, much less race it and besides, I could not afford a CB1100R, a more appropriate choice.

[Warwick Biggs]

Here is a better shot of that dogbone. You can see a dimple in the thread just below the body of the shock. That is an indicator to warn you not to wind it out any further. When that appears you are at the limit. I would actually like another 5-10 mm length but it is already at or close to the limit of what I can run. Anything longer will push the swingarm angle beyond the ideal 12-13 degrees and the chain will start to foul the swingarm bolt.

Roly used the Marquardt frame mods on his chassis to overcome the clearance issue on his twin shock 'Beast' and I don't have that mod. 18" wheels would help but then it is hard to get racing tyres in 18's that will handle the weight and power of the CBX. Avons are the popular choice in 18's but they were designed for 350's and 500's and they are closing down anyway. Stronger carcass Conti's and Bridgestones are available but only in 150 maximum width - not enuf' for the power.

At this stage I will probably just have to live with what we've got. We'll see how it goes with a stiffer spring at any rate.

[Jeff Bennetts]

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Rick just a FYI, a ZRX 1200 has an 17x5 rear rim, it uses the same diameter axle as the CBX. I run a 99 ZRX Swingarm with a widened by Kosman CB1100F rim, as you know the 1100F rim is a bolt on to a CBX.

[Warwick Biggs]

Very nice Jeff! Unfortunately, it would not be accepted under our rules as it does not look 'period'.

Here are some pics of Jyo Bito's new Prolink arm. Even it would probably fall foul of the eligibility scrutineers because the chain adjustment is too modern! Bito san's new offering should be of interest to the many Prolink owners facing bush and bearing issues but in any event is a bit too expensive for me with our current exchange rate. Those delectable magnesium wheels plus the arm but less the rear brake would set me back over AUD$10,000.

I have also included a pic of my new spring ready to be fitted to the shock and have to correct an earlier error. The markings on my current spring are 59/59 (spring diameter) 220 (spring stiffness in Newton mm) and 120 (spring length).

My new blue spring is rated at 250 Nmm making it about 12% stiffer. I have also purchased a 10 mm longer eyelet extension or dogbone. I may not use all or any of that but it gives me a full range of extensions to compare.

[Warwick Biggs]

That caption is on the wrong pic. It should be on the pic of JB's lower linkage that is quite a different design to the original Prolink. By moving the pivot out of and below the arm the top suspension strut looks to be very close to the tyre. It looks fairly robust but is going to cop a lot of grit 'n gravel from the road and it looks like it needs some sort of shroud to protect the bush. Hard to tell without seeing it in the flesh. No indication at this stage whether it changes the original rising rate ratio.

[Warwick Biggs]

Changing the spring simply involves compressing the old spring a bit (I use a C Clamp), sliding the collar off and reversing the procedure with the new spring. Here it is ready to go back on the bike. Note the new longer dogbone ready to go on as well. This one starts at the full extension of my last one and gives an additional possible 10 mm adjustment. Once installed I will reset the sag but in the meantime, I have to remove all the Prolink bushes, measure and if within tolerances, grease.