7 replies to this topic

[Bob Riebe]

I remembered that at one time Kenny Roberts ran a US team of 500 GP Yamahas, so I was curious and started net surfing.

 

Over an hour later after a lot of dead-end bs, I could not remember the sanctions name, this came up  and I had what I was looking for.

 

https://www.youtube....h?v=SCjICNCorM4

 

There is an interesting 250 rider in the video.                                                     

  Rich Oliver

 

Robbie Petersen

This is one of three photos of Rich Oliver on the 500, but his absolute dominance in the AMA 250 GP class, also on a Yamaha, was the stated reason that class was eliminated.

 

His fellow rider Robbie Peterson, and they battled for the championship.

I did find that two fellows, by the name of Knott and Knipp also raced Two Stroke GP bikes in WERA/Formula USA.

 

Jim Knipp - YZ500 J

 

 

Boonie Knot -  RG500 -- TZ250

 

 

When AMA switched to the support series of Superbike, and Formula USA killed the run-what-you-brung formula, that was the beginning of the slide of motorcycle racing in the U.S. from motorsport headlines to -- do they still do that.

Edited by Bob Riebe, 02 March 2022 - 01:25.

[tonyed]

Most two stroke classes were killed by the 'turnstile' gurus who wanted only bulk not quality.

The All Japan championships had 500s from all the participating factories, eventually killed off by the four stroke brigade and what do we have today, MotoGP.

Twice the engine capacity for equivalent power (don't forget the major factories stopped developing the two stroke twenty years back) how many times more engine components (how much more energy and materials to produce)

Now we have bikes that 'sit and beg' what next 'clowns' riding them (sorry we already have Jack Millar and Daren Bindit  )  

It's all going down the F1 route - 'soon we won't need riders at all' 

 

Anyway we also had the end of season 'Super Prestigio' all riders on production 250 GP machines - sorted the men from the boys.

 

The 500s were the peak, once you reach the peak, wherever you go it's downhill. That said no different to the rest of life really.

 

Over in the UK the GP two strokes gave way to the Japanese Production races where you had 1200cc engines with all the subtlety of a battering ram combined with the handling of a pregnant blue whale that had been drinking too much.

 

Still that's progress as they say in the music industry where 'Laurel Canyon'  gave way to Kyli Minogueulike, then the Spice Girls, and now of course 'music' written and performed on your mobile phone.   

 

I wonder why I have a 1974 TZ 250 A sat in the workshop?

 

i went to look at a 'supertwin' the other day. What  a package for 7 1/2 grand -  couldn't fit it all in the van - so I didn't.

 

Still want a 5KE so I have the first and last 250 TZ.  

[GregThomas]

Here in NZ we're just as much in the grip of the factories fourstroke obsession - and have been for quite a while.

The relatively few 2 stroke racebikes still in use are in our Post Classic racing classes.

Ironically we have probably the current best 2 stroke tuner here - and he's working on Karts mainly.

 

The economics though are starting to level out between 2 and 4 stroke. If you're serious about racing a TZ or RS, you first do a big and expensive rebuild.

Year one is full on racing. Year two is less intense and occasional parades. Year three is parades only. Then another rebuild or relegate it to the lounge.

 

I've recently been involved in rebuilding/sorting a Honda RC30 for racing. The sequence with that will now be exactly the same as the 2 stroke.

The rebuild after it's short race career is likely to be even more expensive - so it's more likely to be a static exhibit.

 

One day your grandkids will ask "did you really race two-strokes gramps ?"

[tonyed]

 

One day your grandkids will ask "did you really race two-strokes gramps ?"

 

And you will be proud to answer  -  YES  - of course that is if you can hear the question after years around 130db two strokes 

Edited by tonyed, 15 February 2022 - 10:18.

[Bob Riebe]

Due to snowmobile racing we still have a number of two-stroke tuners in the Great White North.
Until Yamaha introduced expansion chambers in the early seventies they all used megaphone exhaust two-feet or so in-front of the rider.
Here is a picture of a former factory racing sled; the exhaust has been changed to expansion chamber type but in the late sixties when this machine was factory, those would have been megaphone, exiting a few inches past the sleds hood, i.e. cut the expansion chamber in half and that is where the megaphone would have ended.
I have old magazines showing that , as said, until Yamaha entered, that was the standard method.



The expansion chamber types ran without any sort of mufflers until the late nineties.

[tonyed]

As they say in Scotland  - Ye Cannae Whack It

 

I used to have annual hearing tests at work which, after a couple of times, we curtailed as the upper ranges of the test I could not hear    

[Bob Riebe]

Now for something entirely differnt.

 

[Bob Riebe]

FROM ABOVE:

This is a classic from the archives. Boonie Knott (left) talks to Jim Knipp after the two battled in a WERA Formula One race at Indianapolis Raceway Park in April of 1985.

Boonie Knott talks to Jim Knipp after the two battled in a WERA Formula One race. (Larry Lawrence photo)