Looking for RSC, AHR info

Posted: Tue Jan 13, 2009 2:47 am

I am looking for details on the AHR, RSC HRC Superbikes raced prior to 1983. There have been some rule changes in the Vintage Road Racing Assoc. (VRRA) restricting the use of parts to "period correct". The clock has been rolled back, the bike I ran and the 2nd build won't meet the rule changes. So I am looking for info on what was raced "back in the day"

There doesn't seem to be much of an issue with the "go fast" parts for the engine:

Displacement set at 1100cc plus 5% max, run on Race gas
Carbs restricted to smoothbores unless you have original flatsides
Ignition unrestricted
Header racing style (4 - 1) can be stainless steel
Were any 4-2-1 being run?

Frame must be commercially available and can be braced with a raked/tucked steering head.

Suspension 41mm forks max allowed
39mm forks with GL lowers with modified damper rod (Race Tech Emulator) and a fork brace
Who made 41mm forks prior to 83? Cerrani? Any other manuacturers?

Shocks??
Were the shocks on the factory bikes fully adjustable (compression, rebound damping, spring pre-load, height adjustable)?

Brakes, max 2 piston caliper, rotors restricted to 300mm fixed.
What was the size of rotors were raced and were they floatinig, cast iron?

Wheels, front 18"x3", rear 18"x4", 16" or 17" wheels can be used if built by the factory, Superbike or factory replica GP teams.

What manufactures of rims were raced?
Does anyone know of 17" rims being raced prior to 1983?
Were spoked rims on any superbikes?

I need to verify parts what were used in order to run at VRRA events.

Any help appreciated, Jim.

Posted: Wed Jan 14, 2009 9:25 pm

Ok let’s see if we can tackle some of your questions. First off I hate when racing organizations wants things “period correct” then don’t do the homework necessary to find what is correct.

1. I don’t personally know of any 4-2-1 headers being used on bikes at the time but the concept had been around on the automotive side for years.

2. I think the factory Showa anti-dive forks were larger than 39mm but I’m not 100% sure the size. This really doesn’t matter as you have 39mm fork which are fine.

3. The factory shock were fully adjustable….all you had to do is take them completely apart change the shim packs and fluid weight and reassemble. No knobs or clicks back then……sorry.

4. This is the same “BS” AHRMA is pushing. The 1982 factory Honda superbikes used 4 piston calipers not two piston. In 83 I changed to 4 piston goldline Brembo caliper made for an RG500 GP bike and they are still on my bike. I would have done it sooner if I had the money back then.

5. For the rotors I’m pretty sure full floating cast iron brake were used on the factory bikes from 81 on. And I’m thinking they were more like 330mm than 300mm. I can find out for sure if you need.

6. Factory rear wheels were 4.5 x 18” and the fronts 3.5 x 16 Dymags in 1982. They also ran the gold Morris wheels in earlier years….4 or 4.5 x 18R and 3x18F. No 17” wheels or tires were used available back then. You could use spoke rimes if you wanted but I wouldn’t.

Hope this helps some if you need more info just let me know and I’ll see what I can do. Where are VRRA events held?

Posted: Wed Jan 14, 2009 10:21 pm

My period correct HRC/Kosman front rotors are 310mm full floaters being clamped by AP Lockheed calipers. The rotors with magnessium carriers are mounted to a 18 x 2.5 wide three spoke Dymag. I'm in the process of having a set of reproduction rotors made out of modern stainless alloy. The cast iron disc tend to rust at even the thought of rain,...this does not look very good on a street bike. I must say the performance of the iron rotors is very very good though. My front wheel assembly is picture here:

Tony

Posted: Wed Jan 14, 2009 11:04 pm

jkotsi,
Honda produced a 4-2-1 RSC race kit exhaust system, which was available (at silly money) over here in the UK, this was available in the RSC parts catalog from 1980,
it was certainly used in the US on the works RS/RCB1000's & a few privateers ran it on CB900's in 1981 & 1982.

For us mortals in the UK, HARRIS produced a works collection exhaust system which was a similar 4-2-1 design, I had one fitted in 1981 as did many UK privateers,
Harris also started to remanufacture these systems in the UK a couple of years ago, see http://www.harris-performance.com/

I also used to run a 1981 RSC 1123 C5 kitted motor with 72mm pistons, & I was "told" that AHM ran with overbored 72.5 pistons which would equate to approx 1140cc in the long stoke 900/1100 motor making use of the 5% limit rule.
I also recall Russ Collins ran a 74mm 1187cc kit in a drag racer.

Over here in the UK, Brakes were either tandem twin piston (as CB900F or CB1100R) Streetbikes or opposed twin piston as on the UK RS1123 Maxton Framed Superbikes.
Our Streetbikes rules were closer to the US Superbike Rules, as the UK superbike rules were "almost anything goes" with trick race chassis, 18" Dymags, Cast Discs etc;
these are pics of UK Superbikes

www.vintagebike.co.uk/Bike%20Directories/Honda%20Bikes/pages/Honda-RS1123-81.htm

one even came up for sale last year !
http://www.motorcyclenews.com/MCN/News/newsresults/mcn/2008/april/1-6/apr0208dunlopandsheenracebikesupforauction/?&R=EPI-99583

The only bike I'm aware of that ever ran 16" wheels in 1982 was the FWS1000 which Spencer & Baldwin raced & Joey Dunlop won the 1982 Isle of Man TT on.

Posted: Thu Jan 15, 2009 1:43 am

TigreST wrote:

My period correct HRC/Kosman front rotors are 310mm full floaters being clamped by AP Lockheed calipers. The rotors with magnessium carriers are mounted to a 18 x 2.5 wide three spoke Dymag.

Tony

Tony,

I was convinced AMA F bikes ran two different size rotors, 330mm and 310mm. Yours being the bigger kind and 310 used in 1982. Can you double check, out of curiosity?

You can see them both below on the same 16 inch wheel. Your style looks bigger even with a naked eye.

Posted: Thu Jan 15, 2009 2:33 am

Great you just showed the correct picture to show the best carbs these bikes ever had.

These are the EDVac Quicksilvers. Effectively a rack mounted Lectron designed by the same guy, Red Edmundson.

This carb design was sold by Red to Eldebrock now part of the Harley hop up series of matched parts.

Posted: Thu Jan 15, 2009 2:38 am

sonicrete wrote:

Great you just showed the correct picture to show the best carbs these bikes ever had.

These are the EDVac Quicksilvers. Effectively a rack mounted Lectron designed by the same guy, Red Edmundson.

This carb design was sold by Red to Eldebrock now part of the Harley hop up series of matched parts.

Not that I'm in the market but do Quicksilvers ever come up for sale? How much would they go for?

Posted: Thu Jan 15, 2009 6:56 am

Here is the basic story.

Many years ago I was at a dealer show and got info on Red's latest company,ie EDVac Quicksilvers. Showed the production lines etc. These babies were really expensive even back then. I do not think that many were sold. They were there one year and not the next as I think the company folded.

Now I am at the PRI high performance auto show some years later. At the Edlebrock booth they are showing this similar carb as an addition to the "Power Packages",heads,etc for Harleys. A compliment to the power packages for auto engines,carbs,cams,heads,manifolds. So I ask them if they ever see Red Edmundson any more.

Out from the back steps Red and we have a long talk. Turns out he has had a poor relationship with business partners over the years. His basic flat slide,tapered flat needle,design seen on all of them are his designs. This is Lake Injector, Posa Fuel, Lectron,EI Blue Magnums,then the Quicksilvers. He changed something in the design to get a new patent as he got screwed over the years till Eldelbrock bought him out.

He tells me a story about the "F" factory race effort. I probably have a set of the sand cast Keihins they originally used/tried to use,but were having "jetting problems",and Honda called Red to come to Daytona to help. So he steps off the plane and has the EDVacs in the luggage.

They play with the sand cast Keihins and eventually run record lap times. So now he wants to try these carbs and the Honda mechanics will not let him touch the bike anymore. A phone call has Honda, the man,on an airplane to Daytona. He steps off the plane they are bowing and such to hear him say,"Whatever this guy wants to do you do it". Red could speak Japanese,so knew what he said,and then these guys were all assholes and elbows doing what Red wanted to do.

So they put on the EdVacs and the bike goes out again. The sound on the oval is like a banshee,an angry snarl typical of Lectrons and the bike breaks the record it just set by like 2 seconds. Needless to say these became the "factory carbs" for the race effort.

It was some time later they showed up as an aftermarket carb that I saw later as EDVac Quicksilvers regular people could buy.

There is something about that flat side needle that changes the sound of the bike. Lectrons one of his earlier designs,are 4-1 cable carbs. I had VM Mikunis(cheap) on my race bikes and when changed over to Lectrons plain changes the sound. So I remembered seeing the rack kind and started looking for some and seeing the single kind for Harleys got me to think about it. Thought I would ask,not knowing how interesting it would be to talk to the man that designed them. The flat side down stream of a "fit" needle allows the fuel to explode up out of the nozzle giving the atomization. Much better than a tapered needle in a hole of a normal carb,basically the needle can rattle around with some fuel upstream and some downstream. This is the basics of Red's designs.

Posted: Thu Jan 15, 2009 11:09 am

7Eleven wrote:

Tony,

I was convinced AMA F bikes ran two different size rotors, 330mm and 310mm. Yours being the bigger kind and 310 used in 1982. Can you double check, out of curiosity?

7-11,
I will double check the dia. for sure, easily done, but I'm rather sure that my rotors are 310mm. (12.20 inches) versus the 330mm (12.99 inches). I've thought that the 16" v 18" diameter wheels always made the rotors look bigger on the smaller wheels...less "see through" between rotor and wheel rim.

I'll post the numbers tonight after work.

Tony

Posted: Fri Jan 16, 2009 12:49 am

I was correct in my earlier post. My HRC/Kosman rotors are 310mm. Even the recept from Kosman state "310mm". I was not aware that anybody went to 330 mm's, its possible of course..but I'd just never heard that they did (always the last to know that's me). In a stock bike sense..the 1000RR's up to 2006 only ran to 310mm's. In 2007 the CBR1000RR went to 320mm's, some of the largest rotors I've seen/heard of on a Honda of modern build.

There is a limit of sorts I think. This based on how big a rotor you can fit to given wheel diameter and still have room for the caliper to fit over the rotor and inside the diameter of the wheels inner rim surface.

Hope this helps 7/11.

Tony

Posted: Fri Jan 16, 2009 3:42 am

I just went out to check mine and my Kosman rotors are 310mm also. If you look at the two pictures of the 82 factory bikes the top one does have larger rotors but it is also running Lockhead 2 piston calipers. The other has the 4 piston Nissin. I'm betting that the pads are taller and require a bigger rotor than the Nissin.
Just to clarify one thing, the class rules back then was 1025cc so AHM didn't run a 1140cc motor. AHM had several differnt b&s combos but the most common size was a 1023cc motor.

Posted: Fri Jan 16, 2009 5:02 am

Thanks,

It's more help to Jakotsi than myself. I'm just curious. Sometimes it seems like I'm trying to piece together something out of broken clay shards dug up from the sand. You guys are lucky enough to have hands on with HRC stuff, and were around to see these things run on the track. The top picture is 330mm rotor for sure. Not that it helps since there are almost no factory rotors that big. Ducati ran 320mm Brembo rotor since early 90's.