CBX Racing

CBXs, new bikes, old bikes, cars, trucks, general chat, off topic, this is the place to post it.
Post Reply
Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

OK, I hope this works... I have attempted to upload a better pic of my wheel and rotors. Steve you said you posted a pic of a similar Suzuki rotor but I don't see it?? I have sort of worked out a defence under our rules but I don't think it is very compelling and the onus is on me to show I have replicated something from the period. i could paint the spokes black and hope the scrutineers can't count but the only alternative would seem to be to make up another set of rotors.

R.
You do not have the required permissions to view the files attached to this post.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Sorry Steve, found them. Can anybody guess where the solid 8 rotor set up on the Harris Honda in the pics above originally came from or what it replicates?

R.

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: CBX Racing

Post by EMS »

Warwick Biggs wrote:Sorry Steve, found them. Can anybody guess where the solid 8 rotor set up on the Harris Honda in the pics above originally came from or what it replicates?

R.
Why do you say the Harris Honda has a solid rotor? To me it clearly looks like it has pucks and is a floater... :?: :?

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Yes, EMS, the Harris Honda looks like an attempt at replicating an XR69 floater. My understanding (and I stand to be corrected) is that when Pops Yoshimura was putting together his GS racers he dipped into the Suzuki race parts bin and pulled out rotors made for the square four 500 GP bike.

When I say 'solid' I'm referring to the pattern of the spokes compared to the VTR. Of course it is a floater as is my VTR, albeit disguised a bit.

Our rule bans floaters unlesss a replica of something from the period. However, the Harris has eight spokes and originally the Suzukis had 9 or 10. So it is really all about the appearance. I don't think the Harris is any more an accurate replica of the original than my VTR with the plugged pins is. If I paint my rotors black they will look a bit like the 1100R rotors, at a glance even tho' they had 5 spokes.

It is all very petty and annoying but they are the rules. I do have a legal argument but you can imagine how our scrutineers might respond to a retired lawyer getting up on his high horse. That is why I would like to find anything from the period that looks like my modified VTR rotor. There were a lot of variations around at the time.

Of course all this started with a decision by our powers that be to allow 5.5" rims. I don't remember such wide rims in 1982 but I was in the jungle in Papua New Guinea in the early 80's and there weren't too many race bikes around so I have a 5 year blank in my experience. I could be wrong. It wouldn't be the first time!

Part of the problem is political. The Harris Honda in the pic was built by Rex Wolfenden (the Rex in 'TRex Racing') and his brother Clive who have a thriving business in hotrods. Rex is also on the Historic Racing Rules Committee of Motorcycling Australia. He recently proposed that our period 5 bikes (up to '82) be allowed to run 6" rims so that he can pump even more power out of his hand built hotrods. I admire his skills but not his version of history. Rex is also the eminence grise behind the Island Classic, so I need to find a good piece of terra firma upon which to construct an argument. Or spend more $ I can't afford making up another custom set of rotors.

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: CBX Racing

Post by EMS »

I am amazed that anybody with a sound mind would want ( and be allowed) to go with a 6" rear wheel for a classic racer.
Honda's CB1100R came with a 3.00" x 18" rear for the street homologation bike and a 3.5" was available as an option and is as rare as hen's teeth. (Fortunately, I have one).
Wide rear wheels affect handling in a negative way. I change the 6" rear on my Ducati to a 5.5" for track action and run 185 rear tires on it, just to make it turn better.
I am still at a loss to come up with an 8-spoke period rotor to help you out on your issue, sorry.
But there are many guys here on this forum who have done everything that can be done to a CBX and other bikes and I am sure they know how to solve that problem. I am sure they will come through for you!

The 500cc 1975 Suzuki XR14 racer (the square four, you are referring to) had 8-spoke front rotors. By 1980, Suzi's rotors started to float.

7434

7433

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Well EMS, that reminds me of something my father once said to me when I wanted to put wider wheels on my mum's car to go rallying. They were all the fashion in the 60's. He suggested larger diameter wheels would put just as much rubber on the road for a given air pressure (front to rear, not side to side). I'm sure there is sense in what you are saying for road use but it's very different for the track.

I'm currently using a 3.5" front shod with a 120/60/17, and a 4.5" rear with 165/630/17 Battlaxe slicks and they are a huge improvement on the18" x 3" Bol Dor rims shod with Conti RaceAttacks.

The difference was obvious to me when following that Harris Honda around Broadford when I was still on 18's. Our rules currently allow 5.5" rears and this is what the Harris has fitted. Where I was sliding at the limit and using all the track on the exit the Harris just shot away and kept it neat and tight whilst doing so. The biggest advantage of the wider wheels is the increased amount of power that can be pushed thru' to the ground. This is not really an issue with my CBX which is in a very mild state of tune (altho' the extra ground clearance of the wider tyre and carcass strength for handling the weight are plus the ability to go gang busters into the all important first corner by using tyre warmers) but when you are getting up around 200 hp the amount of rubber on the road becomes critical. As I have said b4 these classic replicas are only a few seconds off MotoGP times.

The Suzucki number 30 in your pic above I have seen b4. I was at Laverton when 'Lucky' Luchinello raced and was beaten by my fellow Phoenix club compatriot, Ken Blake. Giaccomo Agostini was also riding one of the MV's but Luchinello on the factory 4 was the man to beat. In those days Australian riders did not have much opportunity to pit themselves against the world's top riders because of the difficulties and expense of racing in Europe and Ken's victory encouraged many of us to think of the bigger stage. The other bike behind it in the same pic with the kangarooo on the back I'm guessing was one of Jack Findlay's bikes, another great expatriate Australian racer.

I think I will have to paint my rotors black. The anodised bling just draws attention to my problem and the nearest I can find is the 5 rotor 1100R (painted black).

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

Warwick Biggs wrote:Part of the problem is political. The Harris Honda in the pic was built by Rex Wolfenden (the Rex in 'TRex Racing') and his brother Clive who have a thriving business in hotrods. Rex is also on the Historic Racing Rules Committee of Motorcycling Australia.
Maybe get a quote from Rex for a set of wheels and rotors that would comply with the rules. If the price is reasonable, just buy 'em and you'll be covered under his scheming instead of hurt by it. If the price is unreasonable, use that quote as a basis for your petition to be allowed to run your setup which has no racing advantage over the more expensive alternative - except that it makes participation more accessible to people running semi-sane racing budgets.

Or apply aluminum duct tape to both sides of your split rotor spokes before painting them flat black.

OR get a free quote from these folks:
https://www.bikehps.com/isr/isr_brake_discs.html

From their website:
Classic Racer Upgraded Discs
Where racing regulations restrict braking system modifications, we can supply race discs to match your originals' dimensions and general appearance, but using this vastly superior rotor material for improved friction performance and fade resistance over original equipment high-chromium content stainless steel disc to give you winning edge. Please call us to discuss your needs.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: CBX Racing

Post by EMS »

Classic Racer Upgraded Discs
Where racing regulations restrict braking system modifications, we can supply race discs to match your originals' dimensions and general appearance, but using this vastly superior rotor material for improved friction performance and fade resistance over original equipment high-chromium content stainless steel disc to give you winning edge. Please call us to discuss your needs.
These are greatly overrated. They are just cast iron rather than steel. And while cast iron has a superior heat performance over stainless steel, these rotors are not winning you races over other modifications. I ran both stainless steel and cast iron rotors on my 916 on the track and I cannot tell the difference. Maybe I am too slow anyway...

The other point is the wheel width. I am not arguing that you get "more power on the road" with a wider tire, but... I was referring to a 6" wide wheel on a classic racer rather than a 3.5" or 4".
You would want a 6" if you want to run a 200 tire...and that's what I think has more drawback than positive affect over, let's say a 165. I can definitely tell a difference in better handling with 185s on my 916 than with a 195 or 200. Then again, I am sure, I am too slow anyway.

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

EMS wrote: These are greatly overrated. They are just cast iron rather than steel. And while cast iron has a superior heat performance over stainless steel, these rotors are not winning you races over other modifications. I ran both stainless steel and cast iron rotors on my 916 on the track and I cannot tell the difference. Maybe I am too slow anyway...
I've also used cast iron and felt no benefit (as opposed to grippier pad compounds which I'm very fond of) - I suggested this not because I think it would work better than the modem OEM rotors on his bike, but because they could be built to fit exactly and would likely pass scrutineering.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Rick Pope
ICOA Rally Director
ICOA Rally Director
Posts: 2270
Joined: Wed Sep 03, 2003 3:16 pm
Location: Lawrencburg, IN
Location: Lawrenceburg, Indiana

Re: CBX Racing

Post by Rick Pope »

One thing nobody's mentioned is the effect a wider rim/tire has on the chassis. Moving the contact patch further from the center line of the bike adds twisting forces to an already taxed frame/swingarm. At some point, additional traction can't be utilized because the frame won't take it.
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Hmm. All very interesting. I find cast better than stainless for racing - lighter for a given width and noticeably more initial 'bight' but agree its not a major issue. I had a set of cast rotors made to fit my wider Bol Dor rims and its not just the cost but maybe I'm just a perverse old bastard but I think, if the rules allow wider wheels that were never available in the day they should allow modern brakes, at least on safety grounds.

However, few people know better than I that the rules sometimes don't make much sense and you either change them, comply or wear the consequences. Having said that I have found some pics of Moto Martins and Egli's that have slightly similar patterns. I found a Magni that was very close; so close in fact that it turned out to be a VTR rotor!

The VTR was pretty typical of the Honda pattern of the late 80's and 90's after the Rothmans NSR's but I suspect it all started earlier with the Bol Dor and CBX patterns, just longer and more spokes accommodating floaters on the later models. In one way it could be argued that the VTR pattern is derived from the CBX but unfortunately not an exact or really even an approximate replica.

I like the suggestion I get a quote from Rex but I'm sure he would think it 'fishy' as there are plenty of people here like Metalgear who can do these things, albeit at a premium price.

I have decided not to paint the rotors and to 'wing it' and see what happens. Hardly anybody ever asks for my log book anyway perhaps because they are a bit surprised to see an old coot wheel up a CBX. Its over 47 degrees in Sydney today by the way (a new record) and I felt sorry for the Poms playing in the final Ashes match, especially the bowlers. It must have been well over 55 in the sun and the Australian team kept the poor bastards running all day.

R.

EMS
ICOA Member
ICOA Member
Posts: 10151
Joined: Wed Mar 05, 2003 7:55 am
Location: North East OH, ICOA 3904

Re: CBX Racing

Post by EMS »

Here are some quotes concerning Roland Skate's CBX racer:
In the Australian Historic class for rorty air-cooled multi-cylinder monsterbikes called Post-Classic Period Five...
..there can't be many devices today so improbably effective as Aussie Roland Skate's Honda CBX Superbike...campaigned by Michael Dibb
..
there is some 130hp delivered to the back wheel ..through a scrawny 4.50 rear wheel - the widest allowed in Post-Classic racing.
.....
weight gets stopped..by twin front 300mm floating Ford McKernan 6mm-thick cast iron discs...on a 3.50in front wheel off a Honda VTR1000
matched to a 4.50in rear from a ZZ-R600, carrying a 165/55-17 Dunlop, that's as much rubber as the Period 5 rules allow.
7440

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Yes EMS, all that stuff about Roly's CBX is a bit dated now.

That was his twin shock and the Period 5 rules changed after that to allow bikes built prior to 1983 (previously 1980) and allowable rear rim width was increased to 5.5". Later I understand he went to a Metmachex swing arm and had his own battles over whether that was a 'period' replica. His prolink was somewhat different again and he runs Brembo brakes on custom cast rotors. I followed his path with my choice of wheels. At least no disputes on the look of the wheels. But a cheaper path with the brakes.

Roly's race bikes are retired (temporarily, I hope) but I will be visiting him on the way to Phillip Island so that he can have a crack at fine tuning my ignition on his dyno. He knows about the issue with my VTR rotors.

It turned out the Poms had to deal with temperatures closer to 60 degrees yesterday and their captain was briefly hospitalised. I hope we don't have similar conditions for Jeremy McWilliams' team to deal with for the Island. Heat continues....

R.

User avatar
Syscrush
ICOA Member
ICOA Member
Posts: 1714
Joined: Fri Sep 14, 2012 2:29 pm
Location: Toronto, ON
Location: Toronto, ON

Re: CBX Racing

Post by Syscrush »

Holy damn, take care in those temps!
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

Warwick Biggs
Amazing Poster
Amazing Poster
Posts: 952
Joined: Tue Nov 03, 2015 9:23 pm
Location: Australia
Location: Australia

Re: CBX Racing

Post by Warwick Biggs »

Now we have gale force southerlies coming up from the antarctic. More and more extreme weather.

Does anybody have any information on German CBX racer and specialist CBX builder, Joseph Schurger?

I have found a single pic of him in an 80's suit standing next to a fairly advanced looking fully faired Schurger CBX but little else apart from an index reference in German Racing Motorcycles.Is it in the CBX book? I'm particularly interested in any images or technical details of his bikes. Apparently he re-sleeved a CBX and had it making 180hp in race form!
This seems like a mythical figure to me but I am curious, nonetheless. Any leads would be appreciated.

R.

Post Reply

Return to “Daily Discussion: By, For & About CBXers”