CBX Racing

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CBX Racing

Postby Warwick Biggs » Fri Nov 06, 2015 2:34 am

After suffering a stroke 18 months ago that left me partially paralyzed and ended my legal career, I am about to start racing a restored 1982 pro-link here in Australia in our post classic or vintage series with the ultimate goal of competing in the IOM Classic TT. My last race was around 1974 so I don't have any illusions about stellar results but I hope to have a bit of fun.

The machine has Tims sump extension, an 1150 kit, 2 mill oversize valves and modified cams, a stage 3 Dynajet kit and Dyna S coils. Otherwise it is a stock white CBX running the original Showa air shock and reverse comstar wheels fitted with Dunlop GP100 tyres.

I would be very interested to hear from anybody who has experience racing these machines, particularly the original production or lightly modified proddy bikes.

I have already been assisted greatly by Roly Skate who runs the extensively modified 'Beast' here in Oz but am interested in other perspectives and experiences, together with any tips or idiosyncracies.

Warwick.
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Re: CBX Racing

Postby Mouse » Fri Nov 06, 2015 10:15 am

:text-welcomewave: To the group Warwick
The only tip I can share is one I learned while part time crewing for a guy who raced a cranky TR3a Triumph.
When racing stops being fun, it's time to stop racing.
Keep us informed Warwick
Good luck and have fun! :-)
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Re: CBX Racing

Postby steve murdoch icoa #5322 » Fri Nov 06, 2015 2:26 pm

HI ya, Warwick.
If you have the ear of Roland there won't be much else to be added.
A few years ago Jan and a couple other people from the site put together a race bike for Mid-Ohio.
viewtopic.php?f=6&t=5050&hilit=sweepings
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Re: CBX Racing

Postby harvey » Fri Nov 06, 2015 3:12 pm

Warwick,

I wish you the best as you pursue racing! It is a lot of fun, just be sure you bring a lot of money!
harvey

Ride Safe and Ride Often
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Re: CBX Racing

Postby EMS » Fri Nov 06, 2015 6:53 pm

Welcome to the ICOA forum, Warwick!

As Steve said, you are in the best of hands with Roland Skate. There are few who could tell you more about successfully racing a CBX than him.
I do have a little track experience myself, albeit not with a CBX. Still, allow me to make a few points:

You said you will campaign a Prolink CBX.
Will regulations require you to keep the fairing? This will make that bike rather top heavy and not so easy to manoeuver around a race track.
Another issue is, that the Prolink CBX was conceived as a "Sport Tourer". The wheelbase of the bike is 40mm - that is more than 1½ inches - LONGER than the early CBXes. Another negative when trying to negotiate fast turns.
Finally, the front end with the air assisted forks and the vented rotors. Terrible damping response and a lot of unsprung weight.

You seem to have a good motor, but the running gear of the Prolink CBX will have to be addressed.
It very much depends on what the rules and regulations will allow. But I would suggest to get a different front fork with different brakes and wheels, together with a different (slightly shorter) swingarm and different wheel.
Both different front and rear wheel will dramatically increase the tire choice.
Also , see if the regulations will allow you to raise the motor in the frame to give you a little more ground clearance.
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To be misunderstood is the rule.
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Re: CBX Racing

Postby Warwick Biggs » Sat Nov 07, 2015 10:08 pm

Thankyou to you all for the encouragement. I'll post some pics soon.

Yes, I'm aware of the pro-link shortcomings, at least in theory, but it handles well on the road and on 5 December I will soon find out what modification is required on the track at Wakefield Park. I'm hoping maximum air pressure and the high density nylon we stuffed down the forks to remove sag will provide a stable front end but we will see. The fairing and all the road gear is sitting under a tarpaulin in my bottom shed communing with all the frogs our current tropical weather is encouraging (it rains heavily every afternoon but we wake up to glorious clear mornings).

It seems the rules here are sometimes more honoured in the breach - last year at Phillip Island the poms arrived with a box of Harris Hondas that were reputedly running engines manufactured in the 90's when our cut-off for the air cooled superbikes is 1982. They won the series (assisted by a few ex GP riders). And in the UK Michael Dunlop recently did a 127mph plus lap on A Suzuki XR69 at the Isle of Man. Some of these bikes are seriously fast even by contemporary standards.

I am hoping to avoid any radical surgery and just use what Honda originally provided with as few tweeks as possible. Once you start down the road of radical surgery, there is no end to it and it is a classic bike after all. To my mind, its a matter of respect for the designers and being true to the period. Then there is the issue of $, too. So, frame modifications are out, even if allowed - for the moment anyway. Basically, the rules say in great detail that the bike has to look period which means the motors can be made of all sorts of modern materials with corresponding performance improvements provided the cases look the same. More scope is provided with the wheels and frame (I suspect for safety reasons and I do harbour some doubts about 35 year old pressed aluminium comstars) but floating disks are banned (somewhat inconsistently) and the Honda brakes were state of the art, in their day. Stainless is heavy tho'.

Roly's bike has the US frame mods and 17" wheels running slicks. Smaller diameter wheels do provide the opportunity to access the stickiest tyres but on the Honda, involve at least an inch of reduced ground clearance requiring the aforesaid frame mods. So long as I can hustle it around without getting lapped I'll be happy. And I'm thinking its size in a corner should present a bit more of a challenge to the other competitors when it comes to passing. There is some method in my madness.

Although heavy I'm hoping those ventilated rotors will enable repeated late breaking without fading because I don't like people shooting up the inside in kamikaze breaking manoeuvres (as we have seen recently with Rossi, Marquez and Lorenzo). At my age, that's a bit undignified. So I like to brake deep and late, turn and squirt. That's how I remember these things being ridden in their day. I recall still with some wonder Graeme Crosby drifting the front of a Kwakka 9 from memory, under brakes, speedway style. To me, that's part of the appeal of this period and the unlimited bikes. If I was sensible and just wanted the fastest race bike I would campaign a TZ Yamaha, as I've done in the distant past. But that's different.

I'm expecting to have to replace the rear air shock with a conventional monoshock (perhaps a bit longer in the shaft to push weight forward) and perhaps the front springs and valves (altho' Roly runs the original 39mm forks without any issues). But we will see.

Any suggestions or comments appreciated.

Warwick.
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Re: CBX Racing

Postby daves79x » Sun Nov 08, 2015 6:53 am

If you are allowed to change suspension, I'd not venture out on the track without changing the rear shock and re-working the front fork. You will soon discover the hinge in the middle without doing that. It will make world's of difference just doing that and make your journey around the track enjoyable.

If you are going out the first time as-is - I'd air up the front to max (15 psi, I think) and put about 75 psi in the rear. That's the only way to get the bike to behave when ridden hard. And about 38-40 or 40-42 psi in the tires. Good luck!

Dave
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Re: CBX Racing

Postby Warwick Biggs » Wed Nov 11, 2015 12:50 am

Thanks Dave,

The manual recommends a maximum of 57psi in the rear and 13psi in the front which is what I was going to try. Have you run the higher pressures yourself?

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Re: CBX Racing

Postby daves79x » Wed Nov 11, 2015 5:31 am

Yes, we routinely ran 70-plus psi in the rear and 15 in the front when we were actually riding these things hard years ago. I know Mike Nixon does not recommend it as it's hard on internals, but you won't have the stocker on very long anyway. You will be begging to change it to a real shock after a race or two. It'll be good to see what the stock one does, so you can be really impressed by the improvement with an aftermarket one.

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Re: CBX Racing

Postby Gearheadgregg » Thu Nov 12, 2015 8:09 am

Good luck on your comeback, and bike sounds fun !! I had some help from a guy named Larry in Virginia when i lived there back in 2005 , he helped me over the counter at his shop in Newport news VA with the proper fuel pump for my Blown GL 1500, Nice guy !! He told me he was also recovery from a stroke , He also has jumped back on his Bull and is doing much better, Hope to see you also !!! btw...I had No clue as i walked into his shop who he was or lol , his brother got a kick outa me asking about all the trophies around the showroom..and then they walked me back to see his Rocket and the real story of how he got his Nickname ! http://www.larrymcbride.com/news06valdosta.htm
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Re: CBX Racing

Postby FalldownPhil » Thu Nov 12, 2015 12:23 pm

Gregg,
There is a man with some serious credentials. Larry is about as fast as they come. He did dodge
a bullet again recently but is recovering nicely. Something about setting himself on fire as he blew
his bike apart at a couple of hundred miles an hour. His guardian angel was working overtime !!
Best,
Phil
When you are up to your ass in alligators it is sometimes difficult
to remember that your objective was to drain the swamp !!
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Re: CBX Racing

Postby Warwick Biggs » Fri Nov 13, 2015 3:27 am

Well Dave, after taking your advice & discussing it with Hugh Robinson (Robinson Precision Engineering) who does up a lot of local CBX's and Roly, I've ordered a Wilbers rear monoshock from ex Aust GP winner Trevor Manley (who pilots Roly's CBX and who runs his own race suspension business in Melbourne). It won't be here for Wakefield Park so I'll use your pressures as a guide for that. It should be here for Phillip Island tho' and from what he tells me I will definitely need it for the blind lefthander coming up over Lukey Heights. The adjustable ride height should help with the 19"/18" wheels to maximise ground clearance.

We have to run additional alloy crank end plates to avoid cracked cases & oil spills so I loose a few mills there.

Trevor tells me he welds up the holes in the front fork damping rods and simply drills smaller holes as well as running stiffer progressive springs. He gave me the specs but I immediately forgot (hole in the head).

How do I attach a pic to my reply?

Warwick.
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Re: CBX Racing

Postby daves79x » Fri Nov 13, 2015 5:37 am

Are you allowed to put emulators in your front forks? If so, they are the way to go. Good going on the rear shock!

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Re: CBX Racing

Postby Warwick Biggs » Sat Nov 14, 2015 7:35 pm

Yes, I think so but are the Racetech valves really that effective and will they fit into the CBX forks? I have suspected they are a bit of a fashion item.

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Re: CBX Racing

Postby daves79x » Sat Nov 14, 2015 8:32 pm

Everyone that I know that's used them likes them, maybe someone will chime in?

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