650cc production supercharged?

[sheribuchta]

blackdog       if the bike will fit in a class it must run in a class and meet the tire speed rating for the record in that class no matter how slow your bike will or wont run----the M-BG record is 190+ to run in that class your tires will have to be V rated SHAVED or ZR  to 200 MPH   bob may be on the right track with the 130 RWB  ---its the same salt just a different date                                                         willie buchta

[sheribuchta]

blackdog---read 7.B.13 --------7.B.8---------1.b-------willie buchta

[blackdog]

Willie....7.B.13 tells me its not a gonna be a 650 class

7.B.8  gotta have tires rated for the class the bike is in (750cc MPS-BG) 209.911 hard rubber, shaved. not stirred.

And 1.B says if the bike fits any existing class ya can't run for time only.

As General Custer, Casey Jones, and the Captain of the Titanic may have said, "This isn't going the way I planned it"

As a trivial bit: why do the stock turbo bikes ALL have over displacement motors? I think now that to reduce the compression for the blower they use pistons that are shorter. (between dome and wristpin) just my guess.

you folks and this forum have been very usefull and have saved me from a costly drama in the inspection processes, I thank you all for taking the time.

[Beairsto Racing]

Gpz 750 Turbo was 738cc, so not all factory turbos were "overbore".
Why is a ZX14 1352cc? Who knows?

Don't give up, if it was easy, every one would do this.

As suggested, maybe you should run at a USFRA event and shoot for the 130 Club? Again, it would be an affordable way for you experience the salt. I like the fact that you are trying to run on a budget with an old bike that you have worked on yourself.

Cheers,
Scott

[MadDuck]

JimL et al,

There are zr rated tires for 19inch wheels.  It is the front from the H/D v-rod.  Most of the manufacturers make them as the v-rod is still for sale.  There may be a few vendors from the English side of the pond making other sizes in vintage racing as that sport is huge and style is critically important.  Nothing like the look of 19" on a vintage bike.  Best of Luck

Paul

[38Chevy454]

Blackdog, many years ago (85-90) I had a Seca Turbo as a street bike.  You are absolutely correct it will rpm limit out at high 120's mph, as verified on the way to Las Vegas from so-cal on I-15    The shaft drive prevents any easy gearing change I am aware of.

On mine, I removed and plugged the wastegate hose that senses boost, so in effect the wastegate sensed zero boost all the time.  Stock boost is about 7.5 psi, this mod allowed it to get 14.5 psi     The 14.5 is limited by the pressure blow-off safety valve on the back of the carb bonnet.  That became my boost limiter     Cheap and easy power increase, drove it this way for approx 20K miles.  I did splice in a vacuum/boost gage so I know the values are accurate.  Also spliced into factory oil cooler line and hooked up an oil pressure gage; mounted both gages in the top of the dash area right underneath the windscreen.  Used Auto Meter 2 inch gages.

The basic problem with the bike is the poor low-end before boost starts to come up.  The extra weight and low torque made it a dog to take off standing start.  Once on the boost, it would pull like a friend's liter bike, but was a dog until 5000 rpms.  Never had any reliability issues, it was a good bike for commuting and riding around - just not for drag racing or landspeed racing.

[blackdog]

the optimist says the glass is half full,
the pessimist says the glass is half empty,
the engineer says your using the wrong glass.

This isn't the right bike for this sort of thing. Half the challenge was to get it running at all, then to do something usefull. now that means the "RWB" event at BUB.
What I've done to the wastegate is removed the rusted out right hand "muffler" and fit a plug to the pipe. should have the same effect.
the popoff seems to handle the over pressure so far but testing opportunities are limited. It does come on strong after 5000 rpm, with the throttle wide open, can't hardly shift the gears fast enough.

Hey, It's all good.

[blackdog]

how did it turn out? see entry in "BUB rule Questions" under "Blown 653cc in RWB"