1980s 4 stroke pro races

It was at Carlsbad and several top guys rode...RJ and Lechien rode trick Yamahas in the early 80s. DC mentions it in today's Racerhead.

Surely someone will pop in with more details

If memory serves me correctly, most of the bikes were “hybrid” type stuff. This engine crammed into this chassis, etc.... As for tracks? I was thinking Saddleback, maybe Indian Dunes? I remember reading about one of these events in MXA, Rick Johnson rode a homemade Yamaha back when they were yellow. Thinking this was around 82 or so....
That would have made me 8. Prob not the answer you wanted, but it was what I could vaguely recall

Yeah I remember a pic of RJ's Yamaha in one of the magazines. I just seen an MXA online arcticle, it was the World 4 stroke Championships from the 70s to 2010. It didnt say what track though.

It was at Carlsbad for quite a few years that I can remember. I found an old thread on here with this picture of RJ's TT600 Frankenstein bike (love the old YZ 125tank)...

Sully wrote:

It was at Carlsbad for quite a few years that I can remember. I found an old thread on here with this picture of RJ's TT600 Frankenstein bike (love the old YZ 125tank)...

That's the typical Hallman - Eneqvist chassis set up. Done by a few different manufacturers at the time. Starting with the Bengt Aberg GP campaigns. Since made by a lot of manufacturers.

Nothing 'homemade' about it. Nor 'Frankenstein about it. YZ125 tanks were slim, and Aluminium, so, pretty bloody light. Which is what it was all about, given the tonnage of the engine.

I remember joyously unpacking a HL frame that came into Competition Development in my late teens, as a frame maker even then, they were things to be admired. Pro Fab, I think made them.

I think I remember Greg Zitterkopf racing a 4T in the MX Nationals in 89. I believe it was an ATK.

RbR wrote:

I think I remember Greg Zitterkopf racing a 4T in the MX Nationals in 89. I believe it was an ATK.

He did . Also Mike and Phil Larson raced ATKs earlier in those 4 stroke national races. Warren Reid raced one at the Carlsbad USGP too.

RJ on a closer to production TT600


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Jeff Jennings at Carlsbad on a Calvin Franks Honda. Photo Credit: MXA

Troy Lee on a PC Husky 4-Stroke. Photo Credit: MXA

There were always some pretty cool bikes at the thumpernats.



[LINK TO IMAGE]

Wandell wrote:

RJ on a closer to production TT600


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Have a Squizz at the Swingarm and the top chain run - I think it's actually an ATK frame. At least that's what the 'tag' I have on that picture says . Pretty much a one of a kind, I'd think. Similar to the XR600 kits that they made a limited number of.

I think it was 86 - they had problems with it and broke out the Pro Tec HL that he used the year before to race with .

More Pro-Tec Pics

"The four stroke worlds was an easy race for me just because the bike (Hallman/Lundin/Pro-Tec Yamaha) was so good compared to what everyone else was riding. Still, it was a four stroke so it was kinda like a girl with a bad attitude and if you pushed it, it would kick you back! I remember the engine had torque for days…my bike was like a works bike in a field of production bikes."

The spanish Fernando Muñoz testing Yamaha HL in Holland I think...In early 80,s. I believe this bike is very rare prototype.

12" travel, 242 pounds. Wow, 4-stroke MX bikes have come a long way in 37 years.

Good info about the RJ pic on the white thumper. Here's a pic I saved of O'Mara on what appears to be a very close to stock XR500. At first glance it appears to have only a pipe but I'm sure it had more work than that.


OMara3 by Wandell Asbell, on Flickr

Chandler on the Kelvin Franks XR500 at the 1980 USGP. Greatest day of motocross I ever attended
Moates cinderella win. And Chandler booming around on the 4 stroke was awsome. 4 strokes sounded bitchin back then against a field of 2 strokes.

Well picture shows up when I preview but not when I submit post ????

From MXA: This was the starting line at the World Four-Stroke Championships at Carlsbad 30 years ago. That is Johnny O’Mara on the far right on a Honda. A close look at the line reveals one Honda, One Husqvarna and one Yamaha—the rest of the field is mounted on blue-framed ATK 604s. Even O’Mara’s bike was a one-off ATK copy. https://motocrossactionmag.com/rumors-gossip-unfounded-truths-31/

Now we just need a 2 stroke nationals pro race and make all come full-circle.

Just need some 2 stroke nationals now ..

Wandell wrote:

Good info about the RJ pic on the white thumper. Here's a pic I saved of O'Mara on what appears to be a very close to stock XR500. At first glance it appears to have only a pipe but I'm sure it had more work than that.


OMara3 by Wandell Asbell, on Flickr

Correct me if I"m wrong.....but...is the O"show trying to kick the beast over mid flight?

Sully wrote:

It was at Carlsbad for quite a few years that I can remember. I found an old thread on here with this picture of RJ's TT600 Frankenstein bike (love the old YZ 125tank)...

This one is vintage moto porn to me