1974 yamaha YZ250A Completely Rebuilt......Ebay

[74yza]

A's are the preferred rides here in the states because the Vintage classes are 1974 and older . The B's have to run against 75,76,77 models and some of them are light years better in the suspension area (twinshock bikes w/Ohlins or Works shocks, 38mm forks etc) so the B's are mostly for restores not competing on. If given the choice A's are just cooler looking and more valuable here so they are my chosen racebikes.

[Freakshow]

HEy TOm, Davey, anyone i have always been stumped on this part of the frame, none of my A's have anything attatched to it, nor does it seem to serve any purpose i can figure out.  But it must be there for some reason cause it wouldnt just be there to add weight. 

What the hell is it supposed to be for and/or if it was a redundant part that never come out on production what was it they were going to use it for ??  any idea - has always had me wondering ?

my only thought was for a underslung pipe perhaps ?

[firko]

A's are the preferred rides here in the states because the Vintage classes are 1974 and older

It's the same rule here Tom....Pre '75 it is. There's a bit of a story as to why the YZB is allowed in our pre '75 class.
 Back in the early 90's a guy named Jody Mason took our governing body, Motorcycling Australia to task over not being allowed to race his YZB in pre '75. He argued that as the YZB was designated by the Yamaha factory to be a 1974 model he was within his rights ro race his bike as long as the 7" and 4" suspension travel criteria was adhered to. He used the '74 Maico as an example of a bike with too much susprension in stock trim being allowed to race as long as the rear suspension was retro modified back to 4" of travel.
After verification from Yamaha and submissions from racers who raced B models in 1974, Motorcycling Australia very reluctantly had no choice but to allow the YZ 250/360B to compete in pre '75 vintage motocross and dirt track. Ironically Mason never raced his Yamaha YZ250B and soon left the sport. Since that decision was made, a small number of YZB's have from time to time competed but to my knowledge none have shown to have any advantage over any conventionally twin shocked bikes.
This was an extremely controversial situation at the time with many, including myself declaring that allowing the 'B' to compete in pre '75 would cause all sorts of problems but now, nearly 20 years later it's seen that allowing the YZB in had little or no effect on the integrity of the class.

[Davey Crocket]

Geez Freakshow......I thought you where a guru....its for a right hand gearchange and thats what the rear brake cable attaches too....if you look up Terry Goods "mxworksbikes" site and look at Torsten Hallmans prototype YZ, you will see what I mean.

[Slakewell]

HEy TOm, Davey, anyone i have always been stumped on this part of the frame, none of my A's have anything attatched to it, nor does it seem to serve any purpose i can figure out.  But it must be there for some reason cause it wouldnt just be there to add weight. 

What the hell is it supposed to be for and/or if it was a redundant part that never come out on production what was it they were going to use it for ??  any idea - has always had me wondering ?

my only thought was for a underslung pipe perhaps ?

I have often wondered this myself and thought maybe it was for a chain tensioner?

[Freakshow]

Geez Freakshow......I thought you where a guru....its for a right hand gearchange and thats what the rear brake cable attaches too....if you look up Terry Goods "mxworksbikes" site and look at Torsten Hallmans prototype YZ, you will see what I mean.

right hand/ left hand just are double ended shaft and use the same holes in the cases  
are you therefore meaning to say its for a left hand brake pick up ?  if you look at the torston bike the rear brake is on the left but it pivots off the swing arm frame.  THE THING ima talking about is not anything to do with the swingarm area and comes off the lower rail ?
unless we are taking about anothe rbike on Terry goods site ?
I have never seen a part number for a left brake and the sleeve is a differant diameter to the right hand brake shaft so im not convienced.

I need to see a picture with soemthing in there........

My other thought was a rearbrake stay or pivot or again a pick up for an underslung.

[Davey Crocket]

That bracket is for the L/H brake pedal. Did you READ the story about the bike and not just look at the pickies?....send those parts before you read about it!!

[Rossvickicampbell]

and Firko - YZB's were available in Australia in 74 I thought whereas they didn't turn up in the States until 75 - hence being marketed as a 75 model over there but 74 here ?

[firko]

Yeah I think that's correct Rossco, we definitely got the YZB before the Americans. It was the same with the '74 LTR Maico. We got them in late '73 while the Americans didn't get them until the second half of 1974, hense the 74.5 designation in their press at the time. I was told they held off on US release to get rid of the remaining '73 model floor stock. If the forward mounted 74 model had been released at the same time as Europe and Australia got theirs, there would have had to discount a shitload of superseded Maicos.
I suspect it may have been the same story with the YZA/YZB.

[74yza]

The YZB in my opinion should be allowed in AHRMA vintage given the fact that Yamaha won the 1973 World Championship on a monoshocker (Hakan Anderson). I also think that if I was allowed to race it I would be at a considerable advantage due to the fact that the monoshock would let me hit jumps a hell of alot faster than I can with a twinshocker. I only say this because I raced a 75 MX250B in some local modern races and did fairly well against modern tracks and jumps. I won the 40+ class by a good margin and 2nd in the sportsman class (only because a local national race was cancelled) and these races were a breeze w/ my YZA , I can't imagine how it would have been w/ a YZB.   

[Freakshow]

That bracket is for the L/H brake pedal. Did you READ the story about the bike and not just look at the pickies?....send those parts before you read about it!!

Nah just the picies.  still dont mean its in the right place though.  so if his is on the swing arm bolt what did they put one underneath ?  sill japs.

update.  read the words where does it say thats what this bit is davey ?  were talking about the 71 reed bike arent we ?