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Hey Mongo...

Discussion in 'WERA Vintage' started by RZ Racer, Dec 20, 2010.

  1. RZ Racer

    RZ Racer It passed tech LAST time!

    Sold my rd and am getting back to my roots and campaigning an RZ next year in F-2stroke and V-5. A question and a request:

    With all the new top ends available, (Cheetah, Athena etc) what is the displacement limit for F-2 stroke? V5 is clearly spelled out, but F-2 stroke seems a little vague. This is all I could find:

    Formula 2-Stroke

    This is a Vintage Formula class where hybrids up to 1985 are permitted. Alloy race frame of the perimeter type may be used as these were available in the period, but twin spar (“Delta Box”) frames are prohibited.

    Among the eligible Formula 2-Stroke machines are the following: Honda RS 125 (steel frame only); Kawasaki H2, H2R; Suzuki RG250, and GT750; Yamaha RZ350, RZ500, TZ250, and TZ350. Specialty frames, such as Harris, Nikko-Baker and Spondon, are permitted.

    Engine: Aspiration will be natural. Make and model of carburetor is unrestricted provided that the design and operating principle was in use prior to the cutoff date. Internal engine components may be modified, altered or changed as per Chapter 9. Cylinders may be bored to a maximum of .080” singles, .060” twins, and .040” three and more cylinders from the class limit. No turbo charging or supercharging are permitted in any vintage racing machine. Any machine with a dispalcement limit following it in the class rules cannot use these overbores, the listed displacement is absolute.


    My take would be .060" over on a stock bore...yeilding aproximately 372.8cc's. Let me know if I can do otherwise 'cuz those newer top ends look pretty cool, but I definitely want to be legal for F-2 stroke!

    And.....

    Since I'm going to be racing an RZ again, I thought it would be cool to go back to my original username, RZ Racer. Any chance?:beer:

    Thanks,



    Mark
     
  2. Mongo

    Mongo Administrator

    372.8 is how I read it.
     
  3. racertex

    racertex vintage dude

    i'm gonna miss the wine slut!
     
  4. WERA33

    WERA33 Well-Known Member

    That's why i ran v6lw last year because i was over.

    Really see no reason to change it. It will definitely increase the cost of being competitive and obsolete the rz cyls..

    If someone wants to run a big motor there's v6 and v5.
     
  5. hinshaw929

    hinshaw929 Well-Known Member

    This doesn't make logical sense to me when the RZ500 which is also water cooled from the same time frame is included in the class.

    I'll make a formal request that the limit on the RZ350 be raised to 450cc so it is the same as V5 and V6LW.
     
  6. charles

    charles The Transporter

    Well, I did submit that same formal request already, but haven't heard anything yet...and I also petitioned for the inclusion of the Suzuki RG500 (which years ago was eligible but then was mysteriously removed from the list) among other bikes that should be out there with us on Saturday in Form 2-Stroke.
     
  7. WERA33

    WERA33 Well-Known Member

    The rz 500 is a pig. Takes a killer build and someone like Mark Brown to ride it fast.

    Definitely obsoletes the Tz 350's.


    Im mean really...why?
     
  8. charles

    charles The Transporter

    The RZ500 is no slouch and would be a decent competitor...I don't get your TZ350 comment, we've got a real good one coming out in 2011 with Scott Reavis and I will guarantee it will not be obsolete.
     
  9. sreavis

    sreavis Well-Known Member

    Formula 2 stroke

    RZ500 is a poor comparison. The only person I knew that could ride one at speed was Brian Berney and he almost beat Schwantz at the GNF in '85 but Brain was nuts. Back to the displacement issue I am not sure a Banshee based motor with higher displacement (but no power valves) has that much advantage over a well sorted RZ based motor. I think we should be more concerned about filling the grids and if a few more CCs increases attendance then great. I'm playing both sides. If I can't ride a piston port TZ fast enough I'm going to have a power valve RZ to fall back on :)
     
  10. 50Joe

    50Joe Registered User

    I'm not racing Formula 2-stroke anymore but I do think the rule should be changed. Decent RZ cylinders are becoming harder and harder to find. Now, try to find someone to port them for racing duty. This is also a lost art that is disappearing rather quickly. I've had reliability issues with OEM cylinders that I feel are due to the age of the parts and the stress they were put under. Being able to buy an aftermarket cylinder that you can bolt on and keep racing is more important for class longevity than anything else.

    How about a compromise. Clubman and F2 have a 396cc limit on liquid cooled twin cylinder 2-strokes. How about making F-2 stroke have that same limit? Seems like a nice middle ground to me.

    Mark,
    .060 over is not enough for an RZ. You and I both know OEM cylinders can be punched out larger than that and still be raced. I'd rather buy an aftermarket cylinder that is nikasil and already ported. In the long run, this is cheaper than OEM, boring, and porting. And, it will be more reliable.
     
    Last edited: Dec 20, 2010
  11. WERA33

    WERA33 Well-Known Member

    TZ350 vs RZ450.....I know what im bettin' on!!:D Dam i thought you "got me" after all these years!!!
     
    Last edited: Dec 20, 2010
  12. charles

    charles The Transporter

    Let me know when you find that RZ450 on the grid...in the meanwhile, Rus "Gliderman' Beltz put the wood to me and others at Roebling this year on his modified OEM RZ350...is it the machine or is it the rider? Perhaps both. You'll have the chance to make some bets in 2011 when Reavis fires up his TZ350.
     
  13. kenessex

    kenessex unregistered user

    Yo Bro Chuckles,

    I have had the pleasure of knowing and racing with Master Reavis for many years, many more than I have known you, and I look forward to seeing him compete, even if he has not thrown off his 2 stroke yoke, yet.

    Ken
     
  14. CharlieY

    CharlieY Well-Known Member

    Sorry to hear of parts availability issues other than the CB350's....weird, almost like our bikes are getting old or something.

    Hope the hand has healed Mark....good luck with the new bike.
     
  15. Christopher Spargo

    Christopher Spargo Well-Known Member


    You're not going to make me build an RD465, are you?

    How about you can go as big as you want with a stock cylinder? I've heard that sunshine flows out the exhaust ports of those aftermarket cylinders. :) 110hp is not unreasonable for these motors. I'd argue that they're hardly period pieces.

    I realize I only have a dog in this fight every 2 or 3 years, but still...
     
  16. charles

    charles The Transporter

    Now, Chris, you know that certain classes in WERA vintage allow modifications so we're really not trying to race 'period pieces' in those classes, that's not the goal. Even AHRMA created an opening in Formula Vintage for TZ's of all sizes, H2Rs, KR750s, the RG500, TR750, and RZ350's... with "no displacement limit" for the 250 and 350 twins. Modernization doesn't always bring distinctive performance advantages, there's may steps along the road to achieve a 'balanced' machine, and in the long run, never discount the rider.
     
  17. RZ Racer

    RZ Racer It passed tech LAST time!

    Thank you sir!

    :cool:
     
  18. RZ Racer

    RZ Racer It passed tech LAST time!

    As for the hotbed debate on standard vs aftermarket cyls...

    I'll follow Mr Reavis's lead and sit the fence, playing both sides on this one. I'll race and give it 100% no matter what the displacement limit is.

    On the one hand, it does seem silly to adhear to a displacement rule if relaxing it by a small (well, not really THAT small...even 421 cc's is a 20% increase...) amount will bring better grids. AHRMA just did add the rz's in unlimited displacement trim in one of their classes, so there might be some crossover, but that is a new addition for this year, so I'm not sure how much that will factor in right away.

    On the other hand, I just bought a really trick, turn-key RZ with a killer motor package that will basically be totally obslete against a rider of similar skill with modern porting, nickisil and 20% more displacement. I see stock cyls for sale all the time on other boards and it's safe to say that there are a lot more rz's out there right now with standard cyls than there are with aftermarket. (though not necessarily on WERA's grids at the moment...) It's kinda nice to have a stock based class, in addition to the 2 classes where the mods are less restrictive. I mean, if you want to throw your wallet at it, you've got V5 and V6 and the rz has proven to be very competitive in both. (I've finished as high as 3rd in V6lw running on my rd 372.8 in f-2 stroke starting from several rows behinfd v6lw.

    Joe- I agree that .060" isn't enough to run in V5 and V6, but those are bump up classes for the rz and they both allow the better cyls. F-2 stroke is basically an rz class with a few bump up rd's (props to current champ, Dick Gruhn), an occasional H2 and a VERY rare tz350 or rz/gamma 500 entry. Why is the extra displacement needed for the F-2stroke class? Cheaper in the long run? Maybe the very LONG long run, but $1500 for a motor add on that also requires differnet pipes and costly mods to existing pipes is hardly cheap.

    So I guess I'm not really sitting the fence after all and would rather see the rules stay the way they are! (but am totally prepared to kick some a$$ if they don't!) :D


    BTW-I'm truely very sorry for stirring this up. I had no idea that there was a petition to change the rules submitted to WERA already by some of the racers in the class (whom I consider friends) before I posted this and realize this is basically going counter to their proposal. Had I know beforehand, I would have just left it all alone. (though I wouldn't have signed on to support it either.)
     
    Last edited: Dec 21, 2010
  19. 50Joe

    50Joe Registered User

    Chris,
    I have yet to see a 110HP rideable RZ anywhere. Drag bike, yes. Roadracer? No. Even the boys in Australia (ex-GP engineer) with 485cc, powervalves, trick ignition, etc. were only claiming about 114HP.
     
  20. 50Joe

    50Joe Registered User

    Mark,
    I disagree. You're buying a fresh, fully developed bike that Gary Stumm built. How about the new guy getting started? Where does he go today to get a competive ride? Gary? He closed shop years ago? Barlow? He's off in England working on scooters.

    I could put a formula together for a newbie where he could buy off the shelf parts and with the exception of matching the upper case to the cylinders (very easy job to do with a demel) he could bolt it all together and have a fast, reliable mount. I know there are RZ cylinders out there, but they are all very old now. By the time they are ported, etc. it really isn't cost effective. I should know. You need to look at this logically and speak with data.

    RZ cylinders - Let's say a decent set for $300 used.
    Decent porting - $600
    Cool Head - $300

    That isn't cheap. Maybe you can shave off a couple hundred bucks here or there but you typically get what you pay for. My last set of Stage 4 cylinders cost me over $1000 if I really took into consideration all my costs.

    What will YOU do if you blow up that nice Gary Stumm engine? Who will you go to for replacement if the cylinders are trashed? Or, will your season be over?

    I'm trying to speak for the longevity of the class and the little guy who doesn't have the background that you, me, Chris, Scott, Charles, or Jim have. We need to make it viable for a new guy to come into WERA Vintage and not be confused or frustrated.

    I would be happy to share with ANYONE exactly what I have in my motor, how much it costs, where to get it, etc. I won't hide a thing. I want more people out there and if I can help, I will.
     

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