1978 yamaha v4 endurance racer

[VisionMeister]

I was looking for information about this bike and found a couple pictures.
It is possible that development work for this engine made its way into the Vision and V-max motors.
Its a 1000cc V4 built in 1977-1978 era for 24 hour endurance racing.
I think it looks like that cylinders are at 90 degree spacing.
Does anyone know any more about this??

[Rikugun]

That's a prototype shown at the '77 Tokyo Motorshow. I found this article with a mention of a liter sized V4 endurance racer from the early 80's - could it be from the same concept? Apparently never raced but sure looks cool.  :)

http://www.crash.net/motogp/news/70299/print.html

Here's the link to the Classicyams site the pics came from. Interesting site with lots of articles.

http://www.classicyams.com/special-yamaha-bikes/special-yamaha-bikes/yamaha-1977-endurance-racer-prototype.html

[fret not]

Too bad the pics aren't better, and more of them.  To me it looks like the pics are of a 2 stroke V4.  (where would you hide the cams?)  Yamaha was making a square 4 500cc GP bike around that time or shortly after.  It was basically 2 TZ250 cranks in tandem.

[VisionMeister]

look at the two into one convergance of the exhaust and the shape of the muffler. I'm pretty sure this is a four stroke.
If the cams were driven off the opposite side of the photo it would be easy for the cam covers to look like the simple boxes shown.
I'm curious about the bore/stroke dimensions and carburetion vs injection and if Cosworth was involved in this effort. 90 degree cylinder spacing would yield perfect primary balance and also mimic the DFV Cosworth F! engine.

[Rick G]

I have no doubt that this is a 4 stroke  The muffler shape and the similarity to the Vmax , seal it for me.. Besides I have never read of  a Yamaha 2 stroke endurance bike. The inferior milage of a 2 stroke would be a challenge in endurance racing.

[fret not]

Did the article state the bike was never raced?  The exhaust could easily be a couple stingers from expansion chambers fed into a silencer box.  More pics with detail and different angles might help.  It well could be a 4 stroke but from the scant information I remain skeptical. 

The Yamaha race department and development engineers were VERY busy during the 70s, And it would be quite interesting to see what all they had been working on.  Certainly not all projects survived to production.

OK, I found an article with a pic of the left side and a statement that it was indeed a 4 stroke "prototype" but never raced. :-[ ;)

[VisionMeister]

There were teams trying to endurance race tz750's in that era. They were fast and able to lead races such as the Bol D'or but not make it past about the 20 hour mark.

Would you post a link to the article or the picture of the left side?

Thanks

[motoracer8]

I have some photos from the mid 70's of a inline four 2 stroke taken at the Tokyo motor show that was a street bike.

It probbably became the TZ500/750

I have a friend with a Suzuki Gamma, he takes it on Sunday rides from tome to time. It's a 2 stroke square 4.

[Rick G]

In 1966 , my then brother in law and I worked on Building two 4 cylinder Yamaha's . One was two 100 cc twins with the transmission cut off and  grafted into a V4 configuration, with separate crank cases, the second was two YDS3 250 twins , with the cranks assembled end to end , making an in line  4. The plan was to mount a Triumph pre unit trans behind them . The 200 was finished by someone else and actually ran very well. I was not aware of the fate of the 500 in line 4.

[fret not]

Well, this shows a bit of my ignorance re computers, but the article is in the American Motorcyclist magazine, and this is the best I was able to muster.  If you can find the page you need to scroll about 2/3 the way down the page.  There is an interesting interview with Steve Baker on the same page.

I found it in a search on Google, shouldn't be too difficult to track down.  Search terms (1978 Yamaha V4 endurance racer)
           
     books.google.com/books?id=vPgDAAAAMBAJ&pg=PA38&lpg=PA38&dq=american+motorcyclist+steve+baker&source=bl&ots=7Tdk4kF6AW&sig=mn5EsS9kAwEPXmMu416Jra3JQMU&hl=en&ei=PrTaSvvsEYTU8Qa4zd23BQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CBEQ6AEwAg#v=onepage&q=american motorcyclist steve baker&f=false       

[VisionMeister]

I found my way to it... what a great source for historical information.
Though no new information on the v4, I took the time to review other issues for race history and advertising from the 70's

Thanks