Whatever happened to the side valve 4 stroke they built???

The requirement to make a 4 stroke disappeared.

The FIM must have cost the factories a stack of money with that ridiculous rule. The factories should have just told them to shove it, what could they have done.

Buyers of new bikes, 2 or 4-stroke have been helping foot the costs ever since.

Probably cost Doug his 100th win and a bit more!

Remember someone told me that when they were in financial troubles they had to show investors they were developing new technologies or something so they would sell bikes..

But probably mainly the fim wanting to introduce 4t's.

low budget crap!! scrap it . side valve , forget it .

cost doug his 100th ? 10 time champion bou .

not too much wrong there!

low budget crap!! scrap it . side valve , forget it .

There's a guy on TC (JSE I think) who has a lot of experience with side valves and reckons done well they are pretty good.

Nothing sounds better than a flathead:-)

There's a guy on TC (JSE I think) who has a lot of experience with side valves and reckons done well they are pretty good.

You must have read one of my articles. I'll count you as one of my 5 fans....

Like I mentioned in the article, the sidevalve is limited in higher RPM situations,

but would be, for a 4T engine, just about perfect for Trials use. Last time I heard,

they had brought in another engineer and were working on valve size/placement. I

think the economy and the "iffy" reception the FIM mandate for 4T's in WTC received

in the Trials world put it on the back shelf for a while.

The design may look very simple, but to optimize it's potential, you have to really

understand how they work. The engineers ought to get hold of one the old factory

Harley flat track sidevalves (pre-XR750), those things were developed to within

an inch of their lives and put out scarey horsepower.

Jon

The gas gas 4 stroked was designed by Queens University in Belfast, the main designer died, I can't remember his name and took vital info to the the project with him to the grave. Gordon Blair?

The gas gas 4 stroked was designed by Queens University in Belfast, the main designer died, I can't remember his name and took vital info to the the project with him to the grave. Gordon Blair?

I didn't know that. Very sorry to hear of Dr. Blair's passing, about a year go as I understand. He was a looming figure in the area of two and four-stroke engine development and I've read a lot of SAE papers he authored. I still use a lot of engine design software developed at QUB under Dr. Blair's supervision.

Jon

You must have read one of my articles. I'll count you as one of my 5 fans....

Don't get ahead of yourself there Jon

I know nothing about them so I'm happy to yield to somebody who does.

Gordon Blair passed away? Sad news indeed but I was under the impression that he was more of a 2T man and more specifically expansion chambers.

*edit* "However, he also decided to start a brand new chapter of work and educate himself in the area of engine design that he had previously had little experience and that was 4-stroke engine valve trains."

from: The late Gordon Blair OBE

Edited September 8, 201114 yr by TooFastTim

Don't get ahead of yourself there Jon

I know nothing about them so I'm happy to yield to somebody who does.

Gordon Blair passed away? Sad news indeed but I was under the impression that he was more of a 2T man and more specifically expansion chambers.

*edit* "However, he also decided to start a brand new chapter of work and educate himself in the area of engine design that he had previously had little experience and that was 4-stroke engine valve trains."

from: The late Gordon Blair OBE

Dr. Blair did do most of his research on the two-stroke from what I gather. I knew of him mostly through the software development. There is a lot of overlap in theory and practice between the two and four-strokes as the Laws of Physics apply equally, so I'm not surprized he would have also been interested in 4T valve systems. I started out working on both two and four-strokes but then specialized in four-stroke design as that was the dominant engine in the type of racing I was doing at the time (dragracing). Later, in the late 60's I also specialized in two-strokes as that was the predominant engine design for the racing I was involved in then (MX, dirt track, roadracing and Trials). I guess one's skill development follows one's curosity and interests.

Walter Kaaden's theories seemed to be driving force in expansion chambers, kinda like Harry Ricardo was for combustion chamber design or Adolph Schnurle for two-stroke porting. Before their innovations, the two-stroke was just an underpowered industrial curosity from what I can see.

Jon