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YZF750 legality

Discussion in 'WERA Vintage' started by yamageezer, Apr 6, 2017.

  1. yamageezer

    yamageezer Well-Known Member

    1994 YZF750 with 1040cc engine. V7HW legal?
     
  2. Mongo

    Mongo Administrator

    I don't think so. If it's an FZR engine it doesn't fit the Superbike rules of a directly interchangeable engine from the same model machine (i.e. FZR400/600).
     
    ricracer16 likes this.
  3. Mongo

    Mongo Administrator

    Now I could see making an exception to allow it since we allow that era 500GP machinery - which essentially makes V7HW the same rules as FUSA was...
     
  4. yamageezer

    yamageezer Well-Known Member

    Grey area since FZR750/1000 YZF750/1000 are pretty much the same thing. So if it has YZF750 cases, it would be legal?
     
  5. Mongo

    Mongo Administrator

    I'd go with yes since then it's a big bore YZF. Silly I know.
     
  6. yamageezer

    yamageezer Well-Known Member

    There was a guy at CMP racing a Harris YZR500!!!
     
    Jon Wilkens likes this.
  7. nhammond54

    nhammond54 Hammond Brothers Racing

    I race the class and I would think yes as well. If you are going to allow a GP bike....why not? Lol.....got to find a GP 500 now....
     
  8. fastfreddie

    fastfreddie Midnight Oil Garage

    Just a bit of nostalgic trivia...

    There was neither an FZR nor a YZF 1000 in '96. When the 1000 returned in '97, it became the YZF by stuffin' the FZR1000 engine into the YZF750 frame.
    That led to quite a bit of retro-fitting. The only mod necessary to make the transition was to drill a hole through the plates on the frame that supported upper engine mounts on the 750 head and add some spacers to take up the gap between the 1000 head and the frame.

    The cases are pretty much all the same for the YZF750, FZR1000 and '97 YZF1000. The big differences are internals. The 750 has a 6pd trans (drops right into the FZR/YZF1000 engines) and the YZF1000 crank is 1kg lighter than the FZR1000 crank.
    The '97 YZF1000 head has two upper frame mounts per side, like the YZF750. It would be interesting to note whether that head, installed on the FZR, would drop right into the 750 frame.

    Losing the FZR frame gains a net loss of 35lbs in weight and supplies the user with fully adjustable suspension...in case there were any questions as to why anyone would do this. The weight savings alone has, in a straight line, the hybrid bike walking away at a good pace. Fully adjustable suspension is the real gravy.
     
    evakat, Phl218 and TurboBlew like this.
  9. britx303

    britx303 Boomstick Butcher…..

    Ah jeeeez,I dont need any more ideas on how to spend more money........this sounds good!:D
     
    evakat likes this.
  10. fastfreddie

    fastfreddie Midnight Oil Garage

    You know there's a guy here offering plenty of options for this, right? It's a steal at $3500, all or nothing. I don't have the room, currently, or it would already be in my possession.
     
  11. britx303

    britx303 Boomstick Butcher…..

    Yes......I know:(:D
     
  12. yamageezer

    yamageezer Well-Known Member

    I was asking for a friend that already has one set up and already races several Ducatis. I have a 88 FZR750 that is working it's way to the track, but it'll be dog slow in comparison.
     
    evakat likes this.
  13. SBKBee

    SBKBee Owner: FZ hotel

    I can fix that, I have a 1040 kit with jug and all...nudge nudge
     
    evakat and yamageezer like this.
  14. Jon Wilkens

    Jon Wilkens Well-Known Member


    They worked that bike in the pits almost non-stop. VERY finicky. But when it was running it was music to the ears!!!!
     
  15. 418

    418 Expert #59

    There was a guy up up north that had was racing V7 and both of his YZF750's had 1000 motors in em. Think he won a few championships too, so it's a little late to deem them illegal.

    Nothing wrong with that IMHO, isn't it a pretty simple bolt in anyways?
     
  16. Mongo

    Mongo Administrator

    Unless it's a 100% exact bolt in - and the engine is from the same model machine - it doesn't meet the rules as they stand.
     
    Jeff McKinney likes this.
  17. 418

    418 Expert #59

    I don't get that. That makes a lot of the ex F-USA bikes illegal, doesn't it? Formula Extreme as well.
     
  18. fastfreddie

    fastfreddie Midnight Oil Garage

    Not to belabor the argument but, V7 is superbike rules, right? And frames and cases can be modified, no?

    The frame modification is simply drilling one hole on each side. Hardly any percentage of alteration.

    The cases are so nearly identical, capable of supporting either engine configuration. I guess, from a technical POV, you would have to put everything into the 750 model designated cases to be legal. Kinda makes it a little more expensive as you now have to have components from two engines to make one...the only tangible difference between the two cases are the casting mark containing the model designation.
    Can the cases can be somewhat modified...unnecessary tabs removed, etc.?
    "Oops, I accidentally ground off the model designation while removing the mounting tabs for the GTS model.":oops: :D

    I know rules are rules but, hell, it's a superbike. That Suzuki never changed its GSX-R model designation over the course of its generations and any 1100/1000 will likely drop into a 750 frame (with minor considerations) kinda puts Yamaha out to pasture just because they chose to call their sportbike something different every generation. An argument could be made that a 1st gen GSX-R is not a Slingshot 2nd gen GSX-R because the frame is different. Does that stop people from puttin' a Slingshot motor in a 1st gen frame? Do the rules disallow that?

    I'm not trying to be difficult, just pointing out what may be an inconsistency.

    Is the FZR600 engine a 100% bolt-in on an FZR400 frame or is that something allowed under different class rules? I'd like, for argument's sake, to be able to use this info in the FZR/YZF conversation, but the model designations for the 600/400 hybrid are the same.

    However, as you may well know, the FZ600 engine is actually the FJ600 engine...Yamaha just put it in a sportier frame to make the FZ. They're kinda convoluted like that. Is that so different from Suzuki using the GSX-R engine in a Katana or a Bandit?
    I can understand not having the rules end up being subject to these convolutions...too many variations on too many different models/MFGs, but which of those hybrid combinations are actually worth doing for a race platform? And one would be disallowed just cuz its name is different?

    The real reason for the existence of the YZF1000 of 1997 is that Yamaha, doing it's convoluted thing, had FZR engines left over but no frames to put them in. They did, however, have YZF750 frames. It was a transition period where they needed to unload inventory that would otherwise go to waste.
    Can you say Banshee? :D

    Don't know if that helps either argument...
    I think I'm being unbiased, while throwing out what I believe to be true, in the event that any rule change/variance might be considered for this particular arrangement of frame and engine but, clearly, I do have a bias. ;)
     
    SpeedyE likes this.
  19. Mongo

    Mongo Administrator

    FUSA was Formula rules, Vintage classes are Superbike rules for the most part but especially for the mid 90's machinery. It wouldn't make the FX bikes illegal as they were superbikes. It would make some but very few of the FUSA bikes illegal sure - but what do you expect from bikes that only ever had one class they were legal for in the US?
     
  20. Mongo

    Mongo Administrator

    Still not a bolt in.

    More than enough people around that could tell the difference in the cases. If they were the exact same then it'd be legal....

    Not all of the GSXR's are a direct bolt in. It has to be a direct bolt in. So the old school 750/1100's are legal. Same for the FZR400/600s. Same as they were when new.

    No inconsistency, same rules have been enforced since the first FZR400 chassis with an FZR600 motor ran C Superbike...

    Straight bolt in, same cases.
     

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