Topic: seeking 1970s pro stock bike regs

[johno]

Probably just going to add to the confusion but when Mark Skehan purchased the pro stock 900 kwaka from RC the V&H  champion winning groovy bike and brought it to South Australia at the end of the season it had (as I remember) the biggest meanest goodyear road race slick I ever saw on a polished  alloy rim and I just wanted one after that.
The confusion bit is Mark also brought back a spare wheel combo with a M&H slick on a all alloy one piece no spokes.

So I dont know which was what but I do know he purchased the bikes and took delivery in the pits after the last run at the last meet of the season so it is likely that he didnt change the wheel and they were running the goodyear road slick, just thought I would add to the mystery Greg 
johno

[Greg H]

I'm sure that the RC Honda P/S bike would have evolved like any other race bike , and would have been subject to changes in spec throughout it's admittedly short life .
I think that I mentioned in a previous post that I wasn't trying to make a carbon copy of any one particular bike but was thinking more along the lines of a generic early 70s bike .
Having said that , I think that  I'll base my bike loosely on the RC bike ,and also incorperate some of my own ideas , because after all, the original  idea was to build the bike the way I would have built it back in the day.

Jon , the points you make regarding tyre choice are very pertinent , so while I have a handle on what  chassis mods I intend doing , I will be giving the issue of which rear tyre/wheel combo to use, some serious consideration .
 
 

[RP]

Here is what I remember on the evolution of the rear tires.  In 1973 and prior, people were using the 18" M&H and/or Avon 4 inch wide flat slick.   Also some used a 15" x 7" car tire slick.  Or they were using what was on that first RC Honda, I have no idea what that could be but they should be some magzine photos of that somewhere.  Then in 1974 or 1975 Goodyear started making a soft compound road race slick with an inch wide spacer added to the mold specifically for drag racing.  It was a round cornered wrinkle wall construction that evolved for over 10 years and then people went to custom built frames and 9 inch wide car tires to handle the new found horsepower.       

[Greg H]

I went down to the storage depot this morning, and look what I found amongst my auto/bike books.


















 
 

[Greg H]

Also found a few old pics of my 970 in sprint/drag/topspeed guise .

[Greg H]

Here's the same bike sprinting in the 750 road legal class .

[Greg H]

Just out of interest in Mike Griffins book it says in the chapter on Pro Stock , that the first P/S race took place at Memphis, Tennessee at the AMDRA's Sunshine Nationals. The first winner was Frank Gilroy on a US Performance sponsored 750 Honda owned by Rich Halverson and Phil D'Vanza .
 The ninth annual AMDRA championship at Atco , New Jersey saw Terry Vance  debut the RC Honda and win his first Pro Stock National victory  .
Looking at the times that were being posted in the early days of the class ( low/mid 10s in the 130 plus range) by some very quick,very talented guys, I'll be happy when I actually get my bike to the strip. if I can get somewhere close to their times . Respect 

[RP]

I actually found a 1973 AMDRA rule book and Pro Stock is not in there, so 74 must be the first year for the class.  I am confussed by the small tired bike in the RC catalog, did it have PRO number plates?  I did see the car tire on the RC Honda at Beech Bend in the summer of 1974.  I did see Byron racing a street tired street bike with a Pro Stock looking engine in the fall of 73 at a Wednesday night test and tune at Irwindale,  maybe they slapped some number plates on that bike for catalog photos.

[RP]

From 1976 Rulebook so this is how it looked in 75....same as I remember in 74 but no wheelie bar.

[Greg H]

Early in 1974, the AMDRA/NHRA issued this press release :
" A major adition to this years program will be the new Pro Stock Eliminator "
" The bikes must maintain a stock frame and the basic stock appearance . The brand name must still remain on the gas tank to help retain the class image ; but the engine department is almost wide open ."
"All of the main body parts (tank, fenders ,forks etc ) must retain the stock shape and size , but lightweight and super trick parts are permitted".
Technical Director Jim Harris notes that a four-inch-wide slick is the maximum permitted .
These are extracts from chapter 5, on  Pro Stock , in Mike Griffins book .