No sound, but here's how it was when I started racing MX:
http://www.youtube.com/watch?v=q_n2m0N3LpQ
Suoercross was in its infancy, 99% of US MX racing was on natural terrain tracks like this. Ah, the good old days...
Speaking of the birth of Supercross: http://www.youtube.com/watch?v=ipNXpHm5QzI
Announced by none other than Dave Despain.
Wow. I just watched this yesterday.
The bikes sure handled a lot better a few years later.
76-79 was when I got into the MX scene. I have no use for supercross, and will no longer race at any of the man made flat field tracks. Aside from a lot of them being dangerous, I just find them boring. Fortunately we still have some good natural tracks locally. You never forget the smell of freshly dug up grass, and premix 
A friend and I were wondering how much fun it would be to have a MX for twins only. Any displacement, any configuration (V-twin, parallel twin, 2 stroke, 4 stroke, etc.) I think that'd be cool...
Here's a good candidate for twin cylinder MX:
http://bringatrailer.com/2011/07/23/very-dandy-138-mile-original-1973-yankee-z/
Back in da day, the British vertical twins were used as MX bikes because they were light. Light being a relative term, ya know.
A Triumph Metisse as it was intended to be used.
Somebody just HAD to build this. Now it's in my list of projects I want to do.
In '65 I ran local tracks with my 175 Jawa. I then graduated to a 250CZ that kicked butt there and was very competitive in the 500cc class. Those bikes had some grunt!
Amazing how much better the late 70's bikes were than late 60's. Some of those looked to have as much as 6" of travel. Not the 14" of today, but the '69 Ossa I learned on had maybe 2".
Development was so rapid in the mid 70's that if you bought a new bike at the beginning of the year, it might be out of date by mid season. The Japanese manufacturers were well known to release new models as quickly as they were able to develop them. It was an interesting time. People think motocross is big now, but it was huge then. If we get 200 bikes to a weekly event now, that's pretty good. Back then, we'd get 3 gates just for 125 junior. That's 120 bikes for one class, and one displacement. There were 10 other classes running.
In reply to Zomby Woof:
Yep, they "sophisticated" it right out of popularity.
Maico used to be THE innovator and were known as the best handling MXer available at the time. They started the long travel revolution way back when in 1975, the other manufacturers were caught napping.
There was a mad rush to play catch up which resulted in some rather half baked ideas. I remember when Dirt Bike did articles on how to modify the various popular MX bikes to move the rear shocks forward for more travel and there were companies making longer tubes for the stock forks, those forks were already flexy at best. Add 4" and they became downright terrifying. Fork braces became BIG business.
Then there were the not so well thought out solutions:
The damn thing just LOOKS terrifying.
Wow, I remember that thing. I don't think I ever saw one on a bike, but I remember those ads.
I moved the shocks up on my 75 CR125 for more travel. The swingarm bent at the new mounting point, but both sides bent the same, so I gusseted it and rode it like that. It turns out that I was an innovator Shortly after that, you could get pre-bent swingarms in the aftermarket.
It's an interesting time in MX now. The Jap bikes have been losing popularity to the Euro bikes for the last 5 years or so, and the 4 stroke is on the decline in a big way. If the Japs don't start selling 2 stroke MX bikes soon, they're going to be in big trouble in the off road market.
I remember the 'banana' swingarms. 
EDIT: I just remembered that one of the articles suggested using skateboard wheels as idlers and clearance guides for the chains on the modified bikes.
A lot of my buddies hate it, but ringdings are in trouble down here. They just don't meet emissions standards and that's a lot of why the high performance 4 strokes were designed and built.
California has bad smog problems due to temperature inversions so they tried red/green OHV stickers (this restricts the area and time of year they can be used) with mixed results and the EPA has been hammering hard on off road 2 smokers as well. At some point, 2 stroke dirt bikes will be relegated to closed course only (MX etc) down here, they won't be legal for use as trail bikes and that's 98% of what they are used for.
It's not just dirt bikes, the 2 stroke weedwacker, generator etc is going to be gone before much longer. Heck, my Ryobi weedwacker is a 4 stroke, it sounds like a little bitty Honda XR.
The Euro manufacturers are developing injected, and direct injected clean 2 strokes.
A lot of the woods guys here are converting back to 2 stroke, and a lot of the MX'ers will be soon. If you go to a hare scramble up here it's predominantly European 2 strokes, and that's going to happen at the mx track too. Nobody can afford the 4 stroke maintenance, especially the 250's. I said about 5 years ago that the 2 stroke would be back, and they all said I was nuts, and it was gone forever. It was just announced that the Canadian MX championship will allow 250 2 strokes to compete against 250 4 strokes. Guess what everybody is buying?
You are right on about Maico. They were way ahead of everybody back then. I remember a time when a guy would lose his factory ride, he's go out and buy a Maico, and compete against the factory teams. It's too bad what happened.
Remember this?
Oh my. I'd forgotten about that. That was near the end for OSSA though, we didn't see many of them here in the States. In fact, I have only seen that setup in pictures, never seen an actual bike.
Dirt Bike did a tour of the Maico factory around 1977? and one of the pictures was a vending machine in the company cafeteria which dispensed beer.
Clean 2 strokes: Honda developed the EXP2 way back when, it was probably the cleanest burning two stroke ever built at the time. For whatever reason after they ran a prototype in Baja (and won their class!) they shelved it.
http://www.motorcycle.com/manufacturer/honda/honda-exp2-14293.html
For whatever reason after they ran a prototype in Baja (and won their class!) they shelved it.
Of course! They'd all four come to the conclusion they had to sell the American market on labor-intensive 4-strokes in order to make the US politicians happy. Everybody has to buy a new bike so everybody makes money. Now they'll do the same thing with 2 strokes. At least, those still involved in off-road riding, which is a demographic the politicians have been trying to kill for decades...
You'll need to log in to post.
