CBX Racing

CBXs, new bikes, old bikes, cars, trucks, general chat, off topic, this is the place to post it.
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steve murdoch icoa #5322
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Re: CBX Racing

Post by steve murdoch icoa #5322 »

With the narrower tank any chance of you bashing the the carbs or velocity stacks with your knees when you are crawling around on top?

Warwick Biggs
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Re: CBX Racing

Post by Warwick Biggs »

Hitting the carbs with my knees? I won't know until I try it but if I do then I can always fit wire 'protectors' on the 2 outside carbs altho' I didn't like the feel of them last time I had them fitted to my straight bank of CR specials. The JB carbs are tilted in like the original CV's and were no problem with the CBX tank but yes, the narrower CB1100 R tank could resurrect the problem. We will see.

Here is a technical question: my cams were ground by a specialist Oz performance firm (Waggott, I think) organised by Hugh Robinson of RPE. Unfortunately, Hugh was unwilling or unable to give me any specs on precisely what they did altho' it is obvious they were simply ground off below the baseline and not built up. More importantly, he did not provide the grinder's recommended valve clearances for shimming. How do I know what are the correct clearances for my motor?

Roly typically runs increased lash on his high lift motors. 0.15-0.2 mm for exhaust (~7 thou') and 0.12-0.15 inlet.

Because I didn't have any special specs from the grinder and was not thinking about it much I set my clearances to the stock recommended by Honda. In doing so I may be sailing too close to the wind if my piston to valve clearance is close. Do members have any thoughts about this?

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Re: CBX Racing

Post by Warwick Biggs »

Apparently not. Oh well, I did not notice hitting the carbs with my knees during the test, at any rate and nor did the closer tolerances cause any issues. Mind you, it was just a test and I wasn't wringing it's neck on the rev limiter but it did feel faster, roomier and easier to move around on. Just a small thing, a narrower tank can have a disproportionate effect on performance.

I did graze the rhs crank end cap tho' so tried dropping the forks the last 5 mills only to find it too slow in the steering so it is now a compromise at about 2.5 mills from the top triple clamp. I just have to try to hang off more. To give you a better idea of how much I have lifted it up; altho' I am over 6 feet tall, I can barely touch the ground and cannot place my feet flat when seated. I now really need a heavier spring at the rear tho' because what was good b4 is no longer and by increasing the swingarm angle it has an exponential effect on the spring due to the nearly 2:1 Prolink ratio. The extra leverage has the effect of putting more weight on the spring thereby affecting sag. It is rideable but as usual, changing one thing affects something else, requiring yet more changes. It is an expensive process of continuous development. We will see how it goes in next w/e's races.

I'm trying to convince Roly to bring the Beast out of retirement for a special race later in the year in our spring. His club can bill it as the clash of the titans, 2 of the most developed historic CBX racers - the Lump versus the Beast. It would be great fun and if you can imagine that with a bit of teamwork, we could create a howling 12 cylinder mobile chicane that the replicas would have trouble passing.

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Re: CBX Racing

Post by Warwick Biggs »

How could I have forgotten to say that the Barnett clutch is a huge improvement over the stock item. And in case you think my stocker was cactus, it was less than 5 meetings old but the plates were already showing signs of burning and that also does the motor no good at all. I can see the benefit in the dry clutch mod.

Now I have more control at the lever, better feel of the cogs sliding into place (less missed shifts) and neutral easy to select even when hot. I can't emphasize enuf' how much of a difference this makes. Who would have thunk it? Well, James Fisher did and he suggested I try it after running one in his racer. Thanks, James. This will certainly help with my starts. And just to make sure all is good for the next race another consumable was replaced when I fitted a new light weight X ring 520 chain in fetching gold. I'm just waiting on the post for the gold Honda wing decals for the tank and all will be ready for our next outing.

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Syscrush
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Re: CBX Racing

Post by Syscrush »

Are you using Barnett springs, too?
Phil in Toronto
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Re: CBX Racing

Post by Warwick Biggs »

Hi Phil. Barnett springs, steel plates and friction plates. The springs and frictions are now hard,if not impossible to get altho' Barnett still do steel plates for the CBX. I scored the NOS springs and frictions from Louis and the steels from Barnett. I was lucky as with the CB1100R race tank as these bits are now all one offs. They make such a difference to rideability.

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Re: CBX Racing

Post by Warwick Biggs »

Here are some pics of the Lump ready to race in next w/e's Seniors races. It almost looks too good to risk crashing but it is going like stink at the moment so it will get a good thrashing.
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Re: CBX Racing

Post by Warwick Biggs »

The Seniors meeting was a disappointment as the Lump DNF'd every race. It ran well and was lapping consistently fast but then just died. It happened 4 times. The apparent cause is the lack of capacity of the new Lithium battery.

I am going to re-design the electrics and try to find a simple light weight low drag generator. I have been told that XR69's ran a stator and rotor arrangement off the countershaft sprocket that sounds interesting but whatever I decide upon it must be reliable and simple, even if it is dedicated to just running the coils.

I also had issues with the NC30. First a mystery electrical fault that took a while to pin point to a sticky solenoid, then a fuel leak from repeatedly pulling the tank off and finnally a loose seat lierally caused by a 12 mm spanner in the works. All of Friday practice was taken up with this tarradiddle altho' I finally managed to get in enuf' laps to scrub in a new rear slick.

After that the little 400 ran without trouble and I scored a podium in the feature Lightweight 100 Plus Cup as well as 4th overall on points in Period 6 500. So at least the w/e was not a total loss but I am running out of patience with the Lump. It has a malicious streak. Here are a few pics showing the new tank in action.
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Re: CBX Racing

Post by Syscrush »

Why not throw another lithium battery at it and keep it total loss rather than the complexity of a generator?
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Re: CBX Racing

Post by Warwick Biggs »

Yes, that is an option Phil. Deltran now offer a 480 CCA battery that is rated at 8 ah that should be stronger than my last Deltran. The fact that it lasted 8 years as my primary battery is testament to it's reliability. The SSB Powersport lithium batteries that the bike shops typically stock are just not up to the demands of starting and running a high compression 3 coil race motor. However, there are now lightweight single phase rotor/stator race set ups that are worth considering as an alternative to total loss.

Most of my competitors user roller starters and only have one or two coils so do not have the electrical consumption of the CBX. However, it is too easy to stall if you miss a shift for example, so I want that button for an easy press restart. That comes with a weight and consumption cost. I have been spoilt by the easy press button running of the little NC30 and it would be good to have that convenience on the Lump.

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Re: CBX Racing

Post by Warwick Biggs »

For reasons that are unclear Deltran batteries are no longer available in Oz.

One of the consequences of doing well in the races is having to hang around and attend to the formalities. Even tho' you might be exhausted after 4 days of racing and just want to get home and put your feet up, you have to pay your respects to your fellow competitors and publicly congratulate them on their achievement while thanking everybody else, including the volunteers, ambos and organisers.

For some reason I managed to get myself into the middle of this geriatric group despite having the smallest trophy but the Seniors tend to be a bit more relaxed about events in general. Older does not necessarily mean slower either, with each trophy holder over the age of 61.
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Re: CBX Racing

Post by NobleHops »

Way to go, Rick!11
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Jeff Bennetts
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Re: CBX Racing

Post by Jeff Bennetts »

Congratulations to you and your team Rick, the Lump looks fantastic by the way! Everyone here knows that feeling when you have been working on something, two or three tries latter it’s all buttoned up and no bueno! Hope you get it figured out soon so you can get that bad boy back on the track, she’s a beauty!

Have you ever considered a handheld Indy style starter?

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Re: CBX Racing

Post by Warwick Biggs »

"Have you ever considered a handheld Indy style starter?"

What is that? I've seen hand held lithium drills used but you can't carry one around if you conk out on the track.

The simplest solution is to run 2 lightweight LiFe Po batteries and use one to start and the other to run the coils with a switch so you can switch from one to the other on the fly. This helps prevent a complete discharge that will kill most lithiums. However, as you switch from 1 thru' both to 2 the voltage jump can also wreck your batteries so that is why the Deltran was good because it could handle the transition. LiPo's are good starting batteries but have terrible ah capacity unless you get a deep cycle LiPo but they weigh as much as lead acid and the lightest gel or agm is around 8 kgs - too much dead weigh on a racer.

A more engineered solution is a small magneto running off the jackshaft producing around 7 amps just to run the coils and allowing for a small loss in the Ignitech digital ignition.

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Re: CBX Racing

Post by Warwick Biggs »

Of course, if I gave up the bubbles I could drop at least 4 kgs but I reckon that is a high price to pay just to win a bike race! I've already given up most other bad habits and there has to be a limit.

Graham, standing to my right only weighs about 65 kgs and races a 20,000 rpm cb250. He can turn just that bit quicker than my 90 kgs on the VFR400 altho' there was only a fraction of a second between us over the line. Bruce on my left on the other hand has the stature of the outlaw mc member that he used to be but rides a 350LC with a TZ motor with more power than Graham and I put together. So he can carry the extra weight.

The biggest impediments on the CBX (after it's geriatric rider) is ground clearance but then weight. At 220kgs wet it is a big lump of a bike and gives away at least 30-50 kgs to the replicas. That is why I choose to put up with LiPo's. But I need a better solution.

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