650cc production supercharged?

[blackdog]

hello to all

this will be my second try at the salt. (2007 B-4501 250cc=64 .333mph)


my question is about the engine class "pb"

 in the 650cc class, is there no record for "production supercharged"?

are there  separate "pb-gas or fuel" class?

following Holdfastgreg's question on displacement (March 23rd 2010) it looks like my 653cc might be in the 750cc class.

the bike came stock with a turbo and some streamlining. so that makes it production, or partial streamlining?

whatever it will be classed as I'm looking forward to running it down the course and maybe setting a new class record.

[Nortonist 592]

653cc puts you in the 750 class.  If you plan to run production the bike must look stock but I believe you can open it out to 750cc.  There is no fuel production class.  Gas only.  If there is no record in the rule book for a class that means its open.  I don't think there is a distinction between faired and naked bikes in production.  Except you can't add a fairing to a production machine that originally came from the factory unfaired.

[wobblywalrus]

Are you going to run at BUB, World of Speed, or Speedweek?

[blackdog]

Are you going to run at BUB, World of Speed, or Speedweek?

speedweek

I really don't know the difference between the events.

now that it looks like a 750cc class, that leaves the frame class,

the stock exhaust has been changed so it's a "modified", but the fairing is stock. is that "partial streamlining"?

do I have this figured right?  "M-PB" or "MPS-PB"?

[Seldom Seen Slim]

Yes, it's "partial streamlined" because of the fairing.  That is, I don't remember the appearance of it -- but anything more than just a headlight -- such as bodywork -- puts the bike into PS.  Modified comes with the non-stock exhaust.  And production doesn't allow anything but a stock (appearing) exhaust, so you're in M(odified)/P(artially) S(treamlined)/Gas or Fuel 750.

There.  That wasn't so bad, was it?  See you on the salt.

[sheribuchta]

750  mps-bg  or 750 mps-bf     The SCTA record at Bonniville are 207 in bf and 209 in bg.  Sheri Buchta

[1212FBGS]

653cc sounds like a CX650 turbo.... if so, plan on entering it as a 750
Kent

[Beairsto Racing]

The factory 650 turbos are all too big for the 650 "production blown classes".

Yamaha XJ 650 Turbo is 653cc
Honda CX 650 Turbo is 673cc
Suzuki XN85 650 Turbo is 673cc

I see the odd beater XJ around Calgary and thought it would make a cheap race bike but realized it wouldn't be legal for 650 production.

[blackdog]

OK......
750cc for the displacement class. (how do the inspectors measure that?)
 "mps" for the frame class, (the headlight is covered)
and the stock turbo makes it a "PB" or did the exhaust mods make it a "BG"? ( I plan to run gas)
or yet another way to look at it, can you have a modified frame and a production motor?



Kent...its a 82 xj650lj

thanks Sheri, 209 wow.

Beairsto.... why do they do that anyway? all the bikes I have ever dealt with were underbored



Thanks for your replies
 

[Beairsto Racing]

If you run it as is, you will be in 750 MPS BG.

Stock turbo or anything else is really no longer a concern because it is not legal for production, on the other hand, you are free to modify it now. The record is high but come out and gain some experience.

Why do these bikes have high displacements? I would have to guess that for all their complexity, they didn't perform that well in comparison to what else was available $$ at the time. The Kawasaki GPZ 750 turbo was really the only factory turbo that performed well and justified the price, thats always been the one that interested me for production. FYI, the Honda CX500 Turbo is legal for 500 push rod production blown because it is 497cc.

If you were to qualify a record and back it up, your engine would be measured in impound. Most often if you are lucky, the inspectors can measure the bore and stroke with tools dropped down through a spark plug hole. Otherwise you will have to remove your cams to disable the valve train while they pump the engine to determine your displacement.

Scott

[blackdog]

my options now are to find parts to make it production again, or find tires to run in a 200+class
a google search didnt turn up zr tires for the 1.85x19 and 2.15x18 rims that were used back then.
with the shaft drive the gearing will run out about 121 or so (if my math is right)
for an open class what tires are required?
 

[Beairsto Racing]

I think you are missing the point...

Your XJ will never be legal for 650 production blown or any other 650 classes as is, because at 653cc, it is over the 650 class displacement limit.

Sleeve the bores to reduce it below 650cc and then run it in 650.

[1212FBGS]

with the over bore allowance he could run in a 650 class just not production, and still probably not competitively.... i can make that thing go 176mph wanna know how?
kent

[JimL]

Uh-oh....watch out!    I hope Kents not thinking of a "J.D. Tibbets" tow with his electric bike!

J.D. was a legend in the desert....he'd carry a tow rope, and give you a tug if you broke down.  Trouble was, he could tow you faster than you knew how to ride!!  None of us ever fell for that twice, lemee tell ya'.

Seriously, though, there are 18" ZR rated tires (front tire from ST1300 for example), but I haven't found 19" ZR rated.  I'm changing the front end on an MPS bike to get 17" and go around that problem.  If you go M class, could maybe convert that thing to chain (theres always a way), use the .020" cleanup allowance, and get into 650 Blown class (though I'm not completely sure that's legal, maybe the engine has to start out as less than class limit, and cleanup takes it over). You could be looking at 153 in M-BG 650.  If you can make and handle the boost, it could be possible! 

Or...you could take out one piston, rod, etc. and run 500cc (you'd be 489cc) where there is no M-BG and MPS-BG is 82 mph!  Just get it running good, put on current tire (won't have to be ZR against an open record or 82 mph), and come on out!  It'll shake, but it's only a couple miles.

You shouldn't listen to me.....I'm bad for weird projects, and it's not always a pleasant experience!

JimL

[blackdog]

Kent....as I understand it the overbore allowance is for motors that start out under the 650 limit and get minor reconditioning, this was manufactured at 653cc. oh well.
so accepting the 750cc class, I must find a frame/engine class that I can run in.
untill recently that ment (to me) any frame (P, M, A, MPS, or APS)with the production supercharger. This will put me in a open class?
what is "PB" if not a factory turbo?

Scott and Kent , thanks for your patiance
JimL ... I like the way you think

OK  Kent, how does it get to 176? draft a 'Busa with the clutch in?