The Perfect Classic Road Racer
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Fast Eddie
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acotrel said:This might be a fun way to go road racing. The class rules should be:
Moto Formula 500 RR
#1 Only air cooled fourstroke single cylinder engines to be used.
#2 Maximum capacity 500cc
#3 No other rules.
This notion that 'rules' are 'bad' in road racing, of any class, is absurd. Rules are there to protect the honest racer. Classes with the fewest rules simply give titles to those with the biggest budgets !! and that would surely apply to your scenario...
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What can you do to a 4 valve Jawa motor to make it faster by spending money, other than what has already been done in the factory ? The 6 speed TTI gearbox would become essential almost immediately. A Seeley frame based bike might be marginally better than a featherbed. I suggest it would become pretty much a level playing field without putting ourselves into the rules straight-jacket. Do you believe the bike in the photo above would be faster than a Molnar Manx or a Walmsley G50 ? It would almost certainly be less reliable on the bigger circuits e.g. IOM .
The point I am making is that the Jawa motors are widely used throughout Europe and secondhand ones are cheap - shouldn't we be using them ? They are cheap bolt in power, and they are a real racing motor, not a converted street engine.
In Australia the 2 valve Jawa engine is the cheapest way to be competitive in period 3 historics, why not use the 4 valve motors in a better race class ?
The point I am making is that the Jawa motors are widely used throughout Europe and secondhand ones are cheap - shouldn't we be using them ? They are cheap bolt in power, and they are a real racing motor, not a converted street engine.
In Australia the 2 valve Jawa engine is the cheapest way to be competitive in period 3 historics, why not use the 4 valve motors in a better race class ?
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The costs:
Jawa 4 valve motor (new) $5000.
Seeley Frame and Tanks $5000,
TTI 6 Speed Gearbox $5000.
Wheels and Brakes $3000
Forks $2000
Your fast competitive racer would cost $20000, and it would be brand new. Built out of second hand parts it would probably cost 30% (or more) less. I believe I could build a competitive bike of that type for less than $10,000. And to be honest, once you have the basics, it wouldn't matter how much money you chuck at the bike, it would not go much faster. The class would encourage development, however with those Jawa motors the probability is that the guys would tune them to a stand-still.
Jawa 4 valve motor (new) $5000.
Seeley Frame and Tanks $5000,
TTI 6 Speed Gearbox $5000.
Wheels and Brakes $3000
Forks $2000
Your fast competitive racer would cost $20000, and it would be brand new. Built out of second hand parts it would probably cost 30% (or more) less. I believe I could build a competitive bike of that type for less than $10,000. And to be honest, once you have the basics, it wouldn't matter how much money you chuck at the bike, it would not go much faster. The class would encourage development, however with those Jawa motors the probability is that the guys would tune them to a stand-still.
Fast Eddie
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But there's no age limit remember... "No other rules"...
There's quite a choice of Jap singles to choose from as a base, before changing to new one off cranks, cams, barrel, piston, etc.
Then stick it in a brand new 250 racing chassis.
On slicks.
Then we'll start on turbo charging and fuel injection and super exotic fuel mixes.
"No other rules" remember...
There's quite a choice of Jap singles to choose from as a base, before changing to new one off cranks, cams, barrel, piston, etc.
Then stick it in a brand new 250 racing chassis.
On slicks.
Then we'll start on turbo charging and fuel injection and super exotic fuel mixes.
"No other rules" remember...
So disk brakes are OK then ?
Should be good for 5 or 10 secs per lap ?. (circuit depending).
You can buy any number of 650cc dohc bikes NEW these days, with modern suspension brakes etc,
for HALF of your $20,000 cost.
Come with warranty, and some with leccy starters even.
And recirc oil pumps !!
If there are no rules, could put speedway profile cams in them,
although some of them might be a step back in performance. !
Should be good for 5 or 10 secs per lap ?. (circuit depending).
You can buy any number of 650cc dohc bikes NEW these days, with modern suspension brakes etc,
for HALF of your $20,000 cost.
Come with warranty, and some with leccy starters even.
And recirc oil pumps !!
If there are no rules, could put speedway profile cams in them,
although some of them might be a step back in performance. !
No need to even spend that much,in the UK during the last quater century there was a clubman’s/national series for open 500 race bikes, one was the Hagon using the 500 XR engine;
http://www.racebikemart.com/adverts/HAG ... 809479.php
http://www.bonhams.com/auctions/19285/lot/205/
http://www.ebay.co.uk/itm/honda-cb500-r ... 3a90b39439
http://www.racebikemart.com/adverts/HAG ... 809479.php
http://www.bonhams.com/auctions/19285/lot/205/
http://www.ebay.co.uk/itm/honda-cb500-r ... 3a90b39439
Fast Eddie
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You're both right guys (although one of you missed the 500cc limit rule, c'mon, there were only two rules and you still missed one!) and i agree, a good racer, as you describe, could be nailed together on the cheap. But frankly, thats fairly true of many classes today. It only starts to get really expensive if you want to win!
And that would happen in this class too. Basic and obvious rule... the fewer the rules... the more you can do... and the more it costs!
If this became a popular class, those cheap engines would soon go up in price. And then there'll always be the guys going for bigger bores, shorter strokes, billet everything, etc, etc.
The point is: this would end up just like any other class with respect to cost.
And that would happen in this class too. Basic and obvious rule... the fewer the rules... the more you can do... and the more it costs!
If this became a popular class, those cheap engines would soon go up in price. And then there'll always be the guys going for bigger bores, shorter strokes, billet everything, etc, etc.
The point is: this would end up just like any other class with respect to cost.
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Rohan said:
The Australian Supermono class died because there was no upper capacity limit. It meant that the fast guys bought the big motors which were not reliable enough to cop a beating. It all became too expensive to remain competitive. And putting speedway cams into a 650cc Japanese single is not smart stuff - the bottom end has to stay together. As far as brakes are concerned, the choice should be open to the competitor - discs are much cheaper and in any case drum brakes should have been rightly banned along with pudding basin helmets. It is possible to race a bike with drum brakes against those with discs, however safety becomes an issue when you increase the sensitivity of a drum brake. You are not talking seconds per lap loss if you are a competent rider, however you need to psych yourself up a bit to do it. It wouldn't be my choice.
As far as single cylinder motors are concerned, the 500cc Manx is the ultimate in reliability with acceptable speed. The Jawa speedway motors will cop a beating up to a point, then you throw them away and buy a new one - $5000 for a Jawa motor is not $50,000 for a Molnar Manx or Walmsley G50 motor. The 500cc upper capacity limit is important.
There is an easy fix for the oil pump problem, the replacement pump costs $300. We currently use them on the 2 valve motors in period 3 historics.
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When I built my Seeley Commando 850, I looked at buying a complete JAWA DOHC speedway bike to get the motor. That was in the 70s and the price was $1500. My Mk3 Seeley would have been a beautiful race ride with that motor. Because of the rules in our historic racing, the bike would have been rendered useless, I would never have got a competitive ride on it. The motor would have put it into Period 5 with the Z900 and H2 Kawasakis. Even now there would not be a race class to suit it. It seems a great pity to me that there are so many cheap unused second hand 500cc JAWA speedway motors around, plenty of four speed gearboxes, as well as replica Featherbed, Enfield, and BSA frames which would suit a single cylinder racer, and we are not using them. It is such an easy build - great for beginners. All you need to be able to do is use cardboard and a jigsaw to cut out a set of aluminium number plates, the rest is simply nuts and bolts.
acotrel said:
Thats a laugh !?
Maybe these days, with modern materials and more precise CNC machining.
Someone once said, with a collected batch of broken parts to prove it, that a Manx must be the only thing ever made with at least
20 different modes of self destructing. And practically all of them requiring most of a new motor to fix !
You do see a lot of ex-manx parts at swap meets, mostly for display, in a 'blued condition' as someone put it.
And any historic race meet does seem to add credence to this story, with more dropped valves, bent conrods, broken pistons and cracked cases etc on show...
The G50 came out, eventually, to solve this bugbear ?
The factory reportedly used titanium con rods in the factory race Manx motors, at vast cost back then, to alleviate one problem.
That gave them quite an advantage over the over-the-counter racers. ?
We are talking IoM TT racing here, where heat becomes a problem long term.
A few laps around the block may be different....
acotrel said:
Ever heard of a recent japanese bottom end described as weak or trouble prone ?
Many trail bikes these days put out nearly as much, or more, as a Manx engine did back then,
and speedway cams are probably pushing more low down torque.
Not really a concern at all ?
Where can these $300 oil pumps be sourced.
Fast Eddie said:
Why go with a 500cc rule at all though - the old 500cc class is about dead and gone, there are not too many of these as road bikes these days.
Whereas the 600 or 650 bikes are booming....
So it makes more sense to go with those. ?
The 600 class is already well catered for - with Supersport, and Superstock racing.
Superstock you can buy a 600cc Four off the showroom floor and go racing.
With only routine oil changes needed for a whole season, apparently.
(Don't know if the warranty would cover crash damage though !)
THATS how to get lottsa folks out and racing, AND not too expensive either.
Maybe Alan hasn't been to a race in the past 20 years or so ?
650cc type bikes may be a single cylinder alternative ?
And then there is always bucket racing.
More emphasis on fun...
http://www.ozbucketracing.com/
http://en.wikipedia.org/wiki/Bucket_racing
More emphasis on fun...
http://www.ozbucketracing.com/
http://en.wikipedia.org/wiki/Bucket_racing
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Bucket racing was stuffed when the guys started trying to race two strokes against four strokes. It doesn't matter what capacity allowances you make, the game beomes idiotic.
Rohan, those 600cc dirt bike motors will never reliably cop what a well prepared manx will. And why would you go over-capacity and cop those problems anyway ?
We have period 5 races in which SR500 Yamahas compete against TZ 250s and 250s.
We have period 4 races in which Seeley G50 Matchlesses compete mainly against Japanese two strokes.
We have period 3 races in which the old British 500s race, and people still manage to sneak the odd two stroke past the rules.'
It is all silly stuff and the races don't even sound right, the bikes are of totally different types racing together. It is a dog's breakfast, and I tend to stay away from it.
Rohan, those 600cc dirt bike motors will never reliably cop what a well prepared manx will. And why would you go over-capacity and cop those problems anyway ?
We have period 5 races in which SR500 Yamahas compete against TZ 250s and 250s.
We have period 4 races in which Seeley G50 Matchlesses compete mainly against Japanese two strokes.
We have period 3 races in which the old British 500s race, and people still manage to sneak the odd two stroke past the rules.'
It is all silly stuff and the races don't even sound right, the bikes are of totally different types racing together. It is a dog's breakfast, and I tend to stay away from it.
grandpaul
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Rohan said:
I see a problem with the above statement.
Generally speaking, racing is intended to be about winning. Or else it's not a race.
Vintage bike racing in the U.S. with nothing on the line but pressed particle board with a bit of decal stuck to it is a bit different. In THAT case, I would agree it is more about having fun on various tracks, having fun building your own bike, parading the classics for the public to have fun seeing, etc. The more fun the better. Who won the race is not the most important thing for almost everyone in the paddock, or in the stands.
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If it is racing, it is about competition. If you race and find yourself in a group of about four riders all going for it on similar bikes, that is the best fun. It is not about winning, there can only be one winner, however it shouldn't be made easy for him/her. What I get upset about is historic racing which goes nowhere near history - why bother to do it ? Better to have classic racing and allow the development to happen legally. My suggestion is that a race class for air cooled 500cc four stroke singles with no other rules might provide a real opportunity to have fun.
These days the fast guys in our Period 3 class (up to 1962) ride Molnar Manxs. They are essentially a modern bike, anything else is usually a converted old British road bike - why would you bother ? You won't see which way they went. A few years ago Barry Sheene was riding in our races with a Molnar Manx. It cost $90,000 to get the bike there, FUN ?
As far as riding in parade events is concerned. Have you ever been riding in a race and seen a guy after the flag has dropped, glide blissfully past a brake marker still doing plenty of speed, grab a handful of brake then crash? That is the danger in riding a bike slowly around a race circuit. While you are racing you are concentrating to the maximum, so safer.
These days the fast guys in our Period 3 class (up to 1962) ride Molnar Manxs. They are essentially a modern bike, anything else is usually a converted old British road bike - why would you bother ? You won't see which way they went. A few years ago Barry Sheene was riding in our races with a Molnar Manx. It cost $90,000 to get the bike there, FUN ?
As far as riding in parade events is concerned. Have you ever been riding in a race and seen a guy after the flag has dropped, glide blissfully past a brake marker still doing plenty of speed, grab a handful of brake then crash? That is the danger in riding a bike slowly around a race circuit. While you are racing you are concentrating to the maximum, so safer.